NASA
/ TP--2001-210992
Launch
Vehicle Design
Process:
Characterization,
Technical
and Lessons Learned
J.C. Blair,
R.S. Ryan,
and L.A. Schutzenhofer
AI Signal
Research,
Inc.
Integration,
W.R. Humphries,
Marshall
May
2001
Space
Flight
Center,
Marshall
Space
Flight
Center,
Alabama
The
NASA
STI Program
Since its founding, NASA has been dedicated
the advancement of aeronautics and space
science. The NASA Scientific and Technical
Office...in
Profile
CONFERENCE
to
PUBLICATION.
papers from scientific
Collected
and technical
conferences,
symposia, seminars, or other meetings
or cosponsored by NASA.
Information (STI) Program Office plays a key
part in helping NASA maintain this important
role.
SPECIAL
PUBLICATION.
or historical
information
sponsored
Scientific,
technical,
from NASA
programs,
The NASA STI Program Office is operated by
Langley Research Center, the lead center for
NASA's scientific and technical information. The
projects, and mission, often concerned with
subjects having substantial public interest.
NASA STI Program Office provides access to the
NASA STI Database, the largest collection of
aeronautical and space science STI in the world. The
TECHNICAL
Program Office is also NASA's institutional
mechanism for disseminating
the results of its
research and development activities. These results
are published by NASA in the NASA STI Report
Series, which includes the following report types:
TECHNICAL
PUBLICATION.
Reports of
completed research or a major significant phase
of research that present the results of NASA
programs and include extensive data or
theoretical analysis. Includes compilations of
significant scientific
information deemed
and technical data and
to be of continuing reference
value. NASA's counterpart of peer-reviewed
formal professional papers but has less stringent
limitations on manuscript length and extent of
TRANSLATION.
English-language
translations of foreign scientific
and technical material pertinent to NASA's
mission.
Specialized services that complement the STI
Program Office's diverse offerings include creating
custom thesauri, building customized databases,
organizing and publishing
providing videos.
For more information
research
results...even
about the NASA
STI Program
Office, see the following:
•
Access the NASA
STI Program
Home Page at
http ://www.sti.nasa.gov
•
E-mail your question
help@ sti.nasa.gov
via the Internet
to
•
Fax your question to the NASA Access
Desk at (301) 621-0134
•
Telephone
621-0390
graphic presentations.
TECHNICAL
technical
MEMORANDUM.
findings
Scientific
that are preliminary
and
or of
specialized interest, e.g., quick release reports,
working papers, and bibliographies
that contain
minimal annotation. Does not contain extensive
the NASA Access Help Desk at (301)
Write to:
analysis.
CONTRACTOR
REPORT.
Scientific
technical findings by NASA-sponsored
contractors and grantees.
Help
and
NASA Access Help Desk
NASA Center for AeroSpace
7121 Standard Drive
Hanover,
MD
21076-1320
Information
NASA/TP--2001-210992
Launch
Vehicle
Characterization,
and Lessons
J.C.
Blair,
AI Signal
W.R.
R.S.
Design Process:
Technical
Integration,
Learned
Ryan,
Research,
and L.A. Schutzenhofer
Inc.
Humphries,
Marshall
Space
Flight
National
Aeronautics
Center,
Marshall
Space
Flight
and
Space Administration
Marshall
May 2001
Space
Flight
Center
• MSFC,
Alabama
35812
Center,
Alabama
Acknowledgments
Section 4.3.9 describing the Avionics Design Function was authored by
James Atherton, Charles Morris, Gray Settle, and Marion Teal.
Sections
4.3. I0, 4.3.11, and 4.3.12 describing
Design Functions
Available
NASA Center for AeroSpace
7121 Standard Drive
Hanover, MD 21076-1320
(301) 621-0390
Information
the Materials
were authored
and Manufacturing
by Paul Schuerer.
from:
National Technical
Information
Service
5285 Port Royal Road
Springfield,
VA 22161
(703) 487-4650
PREFACE
The
combined
participated
Saturn Apollo,
X-33,
and
Flight
Center.
modeling,
experience
in the design
Skylab,
various
Space
payloads.
In that capacity,
mentoring
of the authors
activities
associated
Shuttle,
Spacelab,
At present,
over
150 years.
During
programs:
Redstone,
Space Telescope,
are participating
in publications,
and interactive
AUTHORS'
L.A.
Hubble
they
they are active
and advising,
extends
with the following
computer
E-MAIL
in training
course
ADDRESSES
james.blair@msfc.nasa.gov
R.S. Ryan:
robert.ryan@msfc.nasa.gov
Schutzenhofer:
luke.schutzenhofer@msfc.nasa.gov
W.R.
wrhum@aol.com
111
time,
Saturn
Chandra,
activities
development
tools.
J.C. Blair:
Humphries:
HEAO,
that
they
have
I, Saturn
IB,
Space
at Marshall
and teaching,
Station,
Space
process
o
! .......
.............
{D
I ................
•
!
I
I
I
!
|
|
I
I
I
I
!
I
I
1
"E
f-
Z
{D
X
Z
E
a.
o
=:
°_
!
_-._
Ill
Figure 1. Design process overview.
iv
_
FOREWORD
This report
experience
deals
of the authors,
essential
groundwork
design
and advancing
with the design
process
their
and related
associates,
and fundamentals,
design
description
of the design
represented
in figure
process
technology.
itself
illustrates
include
compartmentalization/reintegration,
decision
gates,
IxI and NxN
diagrams,
A reader
concerned
specifically
detailed
how
discussion.
its various
(3) achieving
The description
elements
advances
interact,
in design
given
However,
in section
and the process
with the process
then
serves
process
effectiveness
The initial
address
sections
guidance
information
from
of the report
address
for achieving
a successful
of the process
description
and connections
of the process.
Main
balancing
function
planes,
discipline
can go directly
to section
or
is
elements
functions,
act.
description
for (1) understanding
subtleties
the
is the characterization
4.3. An overview
tree, design
as a basis
(2) incorporating
It extracts
the core of the report
the main elements
subsystem
vehicles.
literature.
and the final sections
process
1 which
for launch
necessary
and efficiency.
4.3 for the
the design
process
and
for a successful
design,
and
TABLE OF CONTENTS
°
2.
INTRODUCTION
1.1
Motivation
1.2
Report
DESIGN
OVERVIEW
................................................................................
.............................................................................................
7
.....................
8
Characterization
2.2
Engineering
Thumbnail
the System ..................................................................................................
Sketch of Process .........................................................................................
ESSENTIALS
,......................................................................
.............................................................................................................................
3.2
Basis of Good Engineering
.............................................................................................
Constraints
......................................................................................................................
3.3
Derived
Requirements
....................................................................................................
3.4
Formal
Design
...................................................................................................
3.5
Categories
of ModelinJActivities
3.6
3.7
Analyses,
Parameter
Test, and Simulation
.......................................................................................
Matrix and Uncertainties
...............................................................................
3.8
Sensitivities
3.9
Failure
3.10
Judgments
3.11
Probing
DESIGN
Criteria
..................................................................................
.....................................................................................................................
Modes
.................................................................................................................
.......................................................................................................................
Questions
PROCESS
..........................................................................................................
CHARACTERIZATION
..........................................................................
4.1
Project
4.2
Technical
Integration
......................................................................................................
Characterization
Model ..................................................................................................
4.3
4.4
5.
PROCESS
...............................................................................................
and Organization
Top-Level
3.1
4.
and Approach
Overview
2.1
2.3
3.
......................................................................................................................
Design
PROCESS
Technical
Sequence
Framework
.........................................................................................
.............................................................................................................
IMPROVEMENT
5.1
Vehicle
Hardware/Software
5.2
Design
Process
....................................................................................................
Technologies
Technologies
......................................................................
.........................................................................................
vii
18
19
24
24
24
24
24
25
26
27
27
27
28
28
31
32
40
43
150
168
168
168
TABLE OF CONTENTS
6.
7.
ILLUSTRATIONS
6.1
Overview
6.2
Design
OF PROCESS
of Space
Process
for Flight
EXPERIENCE-BASED
7.1
Survey
7.2
7.3
Design
Lessons
of Experienced
9.
RECOMMENDATIONS
A--NxN
APPENDIX
B--SPACE
APPENDIX
C--GLOSSARY
BIBLIOGRAPHY
History
From
Phase
With
Loads
Modeling
Mechanics
A Through
Phase
Example
C ................
..........................
...................................................................................
Practitioners
in Aerospace
.........................................................
173
186
196
196
202
203
....................................................................................................
209
............................................................................................................
210
SUMMARY
APPENDIX
REFERENCES
Design
Suggestions
From Selected References
..............................................................
Learned .............................................................................................................
CONCLUDING
Alphabetical
Definitions
173
.............................................................................................
KNOWLEDGE
8.
C.1
C.2
Shuttle
(continued)
DIAGRAM
SHUTTLE
FROM
REFERENCE
PARAMETER
2 ...........................................................
MATRIX
ITEMS
..........................................
..........................................................................................................
Index ..............................................................................................................
..........................................................................................................................
211
213
222
222
225
.................................................................................................................................
232
............................................................................................................................
234
viii
LIST
,
Design
process
,
Product
evolution
*
STS design--highest
OF FIGURES
overview
........................................................................................................
cycle
..........................................................................................................
order
challenge
.....................................................................................
4.
Design
process/life-cycle
flow
5.
Influence
of aerospace
infrastructure
6.
Top-level
compartmentalization
7.
Categories
of compartmentalization
of design
8.
Illustration
of design
with structures
9.
Design
10.
Design/discipline
interactions
11.
Structural
process
12.
Design
13.
Successive
14.
Design
process
15.
Major
project
stages
16.
Project
phases
.........................................................................................................................
17.
Project
main products
.............................................................................................................
18.
Project
total technical
effort
19.
Typical
project
20.
Typical
organizations
process
and specialization
of design
stack
compartmentalization
design
process
function
...............................................................................................
process
in design
........................................
................................................................
process
..........................................................
plane
and reintegration
example
......................................
........................................................
.................................................................................................
flow ................................................................................................
flow
...............................................................................................................
refinement
............................................................................................................
overview
........................................................................................................
................................................................................................................
management
rate distribution
organization
.........................................................................
..............................................................................
..............................................................................................................
ix
iv
4
7
8
9
10
12
14
15
16
17
17
23
3O
33
34
35
36
36
37
LIST
OF FIGURES
(Continued)
21.
Integrated
product
22.
Technical
integration--T-model
...........................................................................................
40
23.
Technical
integration--activities
distribution
42
24.
Launch
25.
Fuel tank example:
26.
Technical
integration
27.
Matrices
of input/output
28.
Design
process
balancing
act ................................................................................................
50
29.
Design
process
technical
integration--system
52
30.
System
design
function
31.
I×I matrix
32.
N×N
33.
System
design
function
34.
Design
process
technical
35.
Aerodynamic
36.
WBS
37.
Aerodynamic
38.
Design
process
technical
39.
Trajectory]G&N
design
40.
WBS
41.
Trajectory
vehicle
teams
hardware
matrix
subsystems
functions,
of system,
design,
and discipline
design
data flow
...............................................
and discipline
functions
functions
.......................
.......................................
.......................................................................................
design
function
...........................................
44
45
48
49
plane
...............................................................................................
53
vehicle
................................................................................................
56
vehicle
.............................................................................................
57
gates
...............................................................................................
59
integration--aerodynamic
function
2.3--aerodynamics
plane
function
function
gates
design
environments
..................................
..........................................................
.....................................................................................
integration--trajectory]G&N
function
function
.....................................................................................
and induced
2.2--performance
design
compartmentalization
design
for launch
design
......................................................................
Subsystems,
for launch
39
......................................................................................................
plane
and trajectories
design
functions
...........................
63
64
65
67
70
................................................................................
71
design
72
process
flow diagram
...............................
gates ...........................................................................................
X
74
LIST
OF FIGURES
(Continued)
78
42.
G&N
43.
Design
process
technical
integration---control
44.
Control
design
function
plane ...............................................................................................
45.
WBS
2.6--guidance
and control
46.
Control
design
gates
47.
Separation
48.
Design
49.
Structure
50.
Structure
51.
WBS
2.4---structures
analysis
52.
WBS
2. l--vehicle
configuration
53.
Design
process
technical
integration--thermal
54.
Thermal
design
function
plane
55.
WBS
56.
Thermal
design
function
gates ..............................................................................................
108
57.
Design
process
technical
integration--propulsion
112
58.
Propulsion
59.
WBS
60.
Propulsion
61.
Design
process
technical
integration--avionics
62.
Avionics
design
function
plane .............................................................................................
design
function
function
system
process
gates
..................................................................................................
design
design
process
function
...........................................
flow diagram
...........................................
integration--structure
design
function
plane
design
function
gates .............................................................................................
design
design
function
2.8--propulsion
design
function
function
........................................
design
flow diagram
...............................................
and structural
design
process
flow diagram
design
function
..........................................
....................
.............................................................................................
plane
flow ...............................................................................
function
.....................................
.........................................................................................
design
process
flow diagram
...............................................
gates ..........................................................................................
design
xi
function
91
94
process
design
86
92
............................................................................................
process
system
design
83
85
gates .................................................................................
technical
2.5--thermal
82
...............................................................................................
and clearance
81
.........................................
94
95
105
106
107
113
114
115
122
123
LIST
OF FIGURES
(Continued)
63.
Avionics
systems
design
64.
Avionics
process
flow diagram
65.
Avionics
system
design
function
66.
Design
process
technical
integration--materials
67.
Materials
function
plane ............................................................................................
68.
WBS
69.
Materials
70.
Design
71.
Manufacturing
72.
WBS
73.
Manufacturing
74.
Representative
design
2.9--materials
interactions
......................................................................
.............................................................................................
gates .................................................................................
and processes
design
design
process
function
flow diagram
........................................
.......................................
124
125
127
132
133
134
function
gates ............................................................................................
136
technical
integration--manufacturing
140
design
process
process
design
function
2.14--manufacturing
design
percentage
function
...............................
plane ...................................................................................
design
function
design
process
gates
of system
flow diagram
...................................................
...................................................................................
life-cycle
141
142
143
cost determined
as a function
of design
stage .................................................................................................
150
75.
Cost overruns
in NASA
programs
151
76.
Quality
.........................................................................................................................
77.
Conceptual
design
stage--sizing
and functional
78.
Conceptual
design
stage--process
for more
lever
(Structures/thermal/flight
........................................................................................
mechanics
flow sequence
indepth
perspective.)
..........................................
152
153
assessment.
..............................................................
155
79.
Conceptual
design
stage--overall
integration
......................................................................
158
80.
Conceptual
design
stage--options
and ideas ........................................................................
159
81.
Design
process
82.
Space
Shuttle
activities
interactions
history--example
Phase
...................................................................................
A configurations
xii
.....................................................
167
175
LIST
OF FIGURES
(Continued)
176
83.
Space
Shuttle
history--Phase
A concept
84.
Space
Shuttle
history--Phase
B ...........................................................................................
85.
Space
Shuttle
history--Phase
B baseline
configurations
.....................................................
179
86.
Space
Shuttle
history--example
Phase
B' configurations
....................................................
181
87.
Space
Shuttle
history--example
Phase
B" configurations
...................................................
182
88.
Space
Shuttle
history--Phase
C configurations
89.
Space
Shuttle
AFSIG---example
parameter
matrix
90.
Space
Shuttle
AFSIG---example
parameter
variations
91.
Overall
concept
92.
Method
to achieve
93.
Illustration
of design
94.
Structural
loads
illustration
95.
Structural
loads
illustration--squatcheloid
96.
NxN
97.
Parameter
98.
99.
matrix
from
for flight
process:
reference
and groups
...............................................
...................................................................
177
185
....................................................
187
.........................................................
188
event
....................................................................................
190
goal ...................................................................................
191
mechanics
performance
studies
structural
loads
.....................................................................
...................................................................................................
approach
for loads ............................................
2 ...............................................................................................
191
192
194
212
matrix
...................................................................................................................
214
Basic
parameters
...................................................................................................................
215
Liftoff
load parameters
.........................................................................................................
XII1
219
LIST
o
System
design
function
tasks .............................................................................................
2.
WBS
3.
Primary
4.
WBS
5.
Primary
tasks for trajectory
6.
Primary
tasks for G&N
7.
WBS
8.
Primary
tasks for control
9.
Example
expansion
of vehicle
10.
WBS
2.4---structural
analysis
11.
WBS
2.1--vehicle
configuration
12.
Primary
tasks
13.
WBS
2.5--thermal
14.
Primary
15.
WBS
16.
Primary
17.
Data
18.
Primary
tasks
19.
WBS
2.9--materials
20.
Primary
2.3--aerodynamics
and induced
tasks for aerodynamic
2.2--vehicle
functions
function
system
.............................
................................................................
task description
....................................
....................................................................
design
design
function
NxN
and structural
66
68
73
75
79
84
.............................................................
87
diagram
task description
60
..........................................................
task description
........................................................
93
.................................................................
96
design
97
task description
..........................
.....................................................................
98
task description
.......................................................................
109
design
.........................................................................
110
design
design
function
function
task description
tasks for propulsion
subsystem
for avionics
design
tasks for materials
task description
.......................................................................................
and control
for structures
management
function
and trajectories
design
tasks for thermal
environments
design
performance
3.6.0---guidance
2.8--propulsion
OF TABLES
design
.............................................................................
function
....................................................................
task description
..................................................................
design
function
........................................................................
task description
....................................................................
design
......................................................................
function
xiv
117
118
126
128
135
137
LIST
OF TABLES
(Continued)
........................................................
142
..............................................................
145
21.
WBS
22.
Primary
23.
Conceptual
24.
Space
Shuttle
history--political
25.
Space
Shuttle
history--Phase
A ........................................................................................
26.
Space
Shuttle
history--Phase
B ........................................................................................
27.
Space
Shuttle
history--Phase
B'. ......................................................................................
180
28.
Space
Shuttle
history--Phase
B" ......................................................................................
181
29.
Space
Shuttle
history--Phase
C ........................................................................................
184
30.
Space
Shuttle
preliminary
design
31.
Space
Shuttle
detail
................................................................................................
32.
Space
Shuttle
change
examples
33.
Space
Shuttle
change
examples--test
34.
Structural
loads
illustration
35.
Structural
loads
illustration--X-33
36.
Structural
loads
illustration--summary
2.14---manufacturing
process
tasks for manufacturing
design
stage
design
function
......................................................................................
160
activities
174
products
design
task description
.........................................................................
......................................................................................
.........................................................................................
and operations
.......................................................
................................................................................................
176
178
186
187
189
190
193
...................................................................................
194
.............................................................................
195
XV
LIST
AFSIG
OF ACRONYMS
AIAA
Ascent Flight Integration
Working
American Institute of Aeronautics
ASSC
alternate
Space
ATP
authority
to proceed
CAD
computer
aided
design
CAM
computer
aided
manufacturer
CC
controlled
convergence
CDR
critical
CFD
computational
CG
CIL
concept generation
critical items list
DCR
design
certification
DDT&E
design,
development,
DMS
data management
DOD
Department
DR
ECLSS
disposal review
environmental
control
EGSE
electrical
ELV
expendable
EMI
electromagnetic
interference
EPA
Environmental
Protection
EPS
power
tank
system
ET
electrical
external
FA
further
addition
FDL
Flight
Dynamics
FM
functional
FMEA
failure
FPR
FR
flight performance
further reduction
FRR
flight
G&N
guidance
and navigation
GD
General
Dynamics
GN&C
guidance,
GSE
IZcs
ground support equipment
interactive
information
and communication
ICD
interface
IPCL
instrumentation
IPT
integrated
ISO
International
Shuttle
design
Group
and Astronautics
concept
review
fluid dynamics
review
test, and evaluation
subsystem
of Defense
ground
and life support
support
launch
system
equipment
vehicle
Agency
Laboratory
manager
modes
and effects
readiness
analysis
reserve
review
navigation,
control
and control
system
documents
program
product
and component
teams
Standards
Organization
xvi
list
LIST
Isp
JSC
specific
impulse
Johnson
Space
L
LEO
liaison representative
low Earth orbit
LSEAT
Launch
MAC-DAC
McDonnell
MCR
mission
mission
MDR
MIU
OF ACRONYMS
Center
System
Evaluation
MPS
main propulsion
MSC
Manned
Space
Center
MSFC
Marshall
Space
Flight
MUA
material
usage agreement
North American
Rockwell
and usage
Center
NDE
NMI
NASA
NPSP
net positive
OMB
Office
OPS
operations
ORR
operational
readiness
review
OSHA
Occupational
Safety
and Health
PDS
product
PDR
preliminary
design
PRR
preliminary
requirements
PSIG
Propulsion
System
QFD
RBCC
quality function deployment
rocket based combined
launch
RCS
reaction
RFP
request for proposal
reusable launch vehicle
RSS
S/W
SAR
list
system
National Aeronautics
and Space
nondestructive
evaluation
RLV
Team
concept review
definition
review
MM
NASA
Advisory
Douglas
material
identification
Martin Marietta
NAR
(Continued)
Management
Initiatives
suction
pressure
of Management
design
Administration
and Budget
Administration
specification
control
review
review;
Integration
also, program
Working
system
root-sum-square
software
system
acceptance
review
SDR
system
definition
review
SEA
statistical
energy
analysis
SLWT
Super
SN
SOA
stress versus number
state of the art
SRB
solid
rocket
booster
SRM
solid rocket
motor
Light Weight
Tank
of cycles
to failure
xvii
Group
readiness
review
LIST
SRR
system
requirements
SSME
Space
Shuttle
main engine
SSTG
Space
Shuttle
Task Group
SSTO
single-stage-to-orbit
STG
Space
Task Group
STS
space
transportation
T/W
thrust
to weight
TCS
thermal
control
TPS
TRIZ
thermal
Russian
protection
acronym
TRL
technology
TSTO
TVC
two-stage-to-orbit
thrust vector control
WBS
work
breakdown
v&v
verify
and validate
OF ACRONYMS
(Continued)
review
system
systems
system
meaning
readiness
"theory
of inventive
level
structure
°,,
XVII1
problem
solving"
TECHNICAL
LAUNCH
VEHICLE
TECHNICAL
PUBLICATION
DESIGN
PROCESS:
INTEGRATION,
CHARACTERIZATION,
AND LESSONS
LEARNED
1. INTRODUCTION
1.1 Motivation
There
is a strong
effectiveness
vehicles
need within NASA
of launching
are essential
characterizing,
payloads
ingredients
understanding,
tive of the former
Understanding
in obtaining
and Dynamics
The goal of this activity
an understanding
and the aerospace
into orbit.
is to enable
of the current
design
the launch
process.
It grew
out of an initia-
Marshall
Space
Flight
Center
effective
and efficient
launch
vehicle
design
by (1) providing
as a basis
reference
guide
design
process.
It examines
Engineering
design
complex
and
challenge
of the highest
Most
significant
new
the design
launch
skill,
challenge
organization,
The
subsystems,
to distribute
extreme
for any product.
energy
vehicles
require
density,
to the current
Since
their
report
guidance
design
process
process.
launch
vehicles
successful
and
characterizes
and provides
the design
very
high
propulsion
efficiency
and
system
parameters,
and
requirements
for performance,
resulting
from the combination
accepted
design
are highly
represents
a
integration,
design
cost, reliability,
of the above
and
involve
mass
efficiency,
advanced
have
technologies.
safety, operability,
and schedule.
factors
the best of engineering
demands
Meeting
and judgment.
approach
to space
systems
is to compartmentalize
the hardware
subsystem
design functions,
and discipline
functions.
The substructuring
is driven by the need
the workload
into manageable
portions, the need to utilize multiple discipline
specialties,
and
the need
to capitalize
decoupling
which
utilization
of the industrial
evolved
have
revolutionize
and efficiency
This
encountered
of improvements
that might
activity
engineers.
problems
an initial listing
in environmental
communication,
currently
common
effectiveness
(MSFC).
order.
uncertainties
They have stringent
and
for improving
for less experienced
technologies
is a challenging
interconnected
addresses
design
process
It also includes
This report
vehicle
process
on advanced
for launch
at NASA
a design
implementation.
the
process
Laboratory
the current
observations
the cost and improve
the design
capability.
and clarifies
and initial
to reduce
launch
(2) providing
for effective
industry
and improving
a low cost, effective
and improving
Structures
and Approach
in industry
on industrial
allows
specialization.
for the distribution
specialization.
to provide
unique
The functional
of the workload
characteristics
to the design
Industrial
specialization
subsystems
(e.g.,
refers
avionics,
of the subsystems
enable
functions
and allows
for the
to the specific
expertise
that has
rocket
engines,
etc.)
and
parts
(e.g.,o-rings,transducers,etc.).Achievingthe highestquality andlowestcostfor a launchvehicleentails
utilizing this specializedexpertiseof the industrialbase.Industrialspecializationalsoprovideshardware
availability andschedulereduction.The specializationalsoenhancestechnologydevelopment.Compartmentalizationresultsin two distinctfunctions:(1)The designfunctionand(2) thedisciplinefunction.The
designfunctionsaresupportedandaccomplishedthroughthedisciplinefunctions.The approachrevolves
around allocating requirements,constraints,etc., to the subsystems,elements,and components.The
hardwareandsoftwarearedesignedandproducedthroughanalysis,testing,simulation,andmanufacturing
processes.The design and discipline functions accomplish thesetasks. As is true with industrial
specialization, this compartmentalizationfocusesspecializationand technology development.The
inherentproblem with compartmentalizationis that it necessarilycreatesartificial boundariesin the
processandorganization.Theseboundariescreatethetendencytowardsandboxingor territorial syndromes.
This
creates
boundaries
communication
have made
When
problems
it difficult,
the process
works
disciplines,
design
decisions
in the iterative
judgment.
In this method,
subsystems,
etc.,
has evolved
along
specialization
iterations
in properly
exchanging
interacting
if not impossible,
to establish
an ideal,
properly
must
design
occur
process
design
or balancing
the specialization
result
and lower
specialties
of universities
and design
it is usually
based on the assumption
It is a generally
stated
understanding
associated
with the process
First,
interactions.
the
higher
communications'
Second,
industry
Third,
components,
function
the
organizations.
The
of weak coupling
the total system.
to a breakdown
performance
compartmentalization
major
of design
etc.
are
more
problems
in communication.
and
Key
separately
designed
previously,
the system
This
standardization
The
design
and
process
takes
follow
from
is applicable
in general;
the subsystems,
design
difficulties
in allocating
are not caused
As a result,
by a lack of
there
are
risks
the
sensitivities
and
interactions,
integration,
and
and understood.
requirements
emphasis
otherwise
these
As stated
approach
between
within
that 80 to 90 percent
there
requirements.
These
and keen engineering
compartmentalization
and interacting
that must be assessed
reliability;
and discipline
cost parts,
and discipline
weak,
extensive
to achieve
test results,
by assembling
is not
but are due
This means
system
simulation,
coupling
axiom
functions,
and academia.
function
discipline
design
of industry
quality
communicating,
subsystems,
(competencies)
standard
however,
requirements,
process.
outputs.
Design
data.
design
conflicting
in higher
If the
total
is accomplished
specialties.
disciplines.
among
and
seamless
between
of these
and
the
on analysis,
advantage
functions,
occur
to converge
are based
the system
and iterating
and interactions
parameters
must
of a system,
be placed
problems
naturally
the
on allocations,
higher
occur.
introduces
boundaries,
setting
up the
tendency
for
nearsightedness.
system
design
must be recognized
as a balancing
ensuring
that the current
approach
act between
the conflicting
requirements
and interactions.
In summary,
allocating
and
refining
technical
integration
requirements,
through
adequate
design
to understanding
communication.
works
sensitivities
requires
proper
and
interactions,
attention
and
be given
to ensuring
to
The first part of the activity reportedhere is intendedto characterizeand baselinethe launch
vehicle designprocess.In section4.3.1, the processhasbeencharacterizedby compartmentalizingthe
systeminto subsystems,
with eachsubsystemhavingdesignfunctionplanesoverlaidwith a systemdesign
function plane.Within eachdesignfunction planeare the contributingdiscipline and designactivities
alongwith outputattributes.This descriptionincludesboth the tasksandhow designdecisionsaremade
fractionallyandincrementallyandhowdesigndecisionsareintegratedinto thetotaldesign.Foreachplane
a flow diagramis developedfor illustrating the various decisiongatesand a descriptionof top-level
attributesto be comparedwith requirements.This approachwas developedto characterizethe launch
vehicledetail designstageand canbe appliedto other designstages;e.g.,conceptualandpreliminary
designstages.
The typicalprocessaspracticedcurrentlyis referredto hereinasthebaseline.The characterization
of the baselineservesasa referencepointfor refining andimprovingthepresentprocess(evolutionary).It
alsoservesas a referencepoint to developrevolutionarytechnologiesfor the designprocessthat could
produce orders of magnitude jumps in process efficiency and effectiveness. The effort
reportedhereis theinitial taskof determiningtheessenceof thelaunchvehicledesignprocess.If weareto
meetthe launchcapabilitydemands,thenbreakthroughmustoccur.
Utterbackin Mastering
the Dynamics
ties in the face of technological
development
of a product
established
specific
product.
phase
change.
in steps.
Second,
and is firmly
attention
to product
for them
in, the product
the company
During
improvement.
will accomplish
bursts
technologies
Swiss
watch.
electric
household
refrigerator
by the parent
figure
manual
replaced
companies.
and
the ice factories.
None
2. So, NASA
and the major
aerospace
industries
1. Delineate
and baseline
the launch
vehicle
3. Implement
the baseline
new innovative
performance
of improvements.
typewriters
concept,
and improve
Third,
were
of these
as discussed
should
design
invading
above,
follow
until
is then
in a
use) continues
to
(sales,
watches
a three-pronged
the process--revolutionary.
to
replaced
processor.
were
to aerospace
process
to advance
or the requirement
by the word
process---evolutionary
technologies
it is an
this is not sufficient
digital
technologies
was applied
the
innovation
However,
replaced
characterizes
the product
technologies
take over. For example,
Utterback's
2. Refine
on product
As invading
can seize opportuni-
also. Utterback
improvement.
this time, the product
or process
as it is, and the invading
The
how companies
concentrates
on process
save the product
jeweled
_discusses
have dealt with the subject
concentrate
established.
rise with minor
come
Others
First,
they
of Innovation
the
The
implemented
as indicated
attack:
in
_,tmBmw
e-
E
Today _
Stage 4--New
ff_
Technologies
o
Stage 2--Incremental
Improvement
CL.
¢,J
o
--
i-
,,.,,_
_z
Stage 3--Burst
,E
.-_
..,._
.....
_7.qt=ge
_,_ 1-Innovation
_....
Improvement
Time
Today
_.
CurrentProduct
__
Stage4--New Product
/
E
Stage I--Innovation; Stage 2--Incremental Improvement;Stage g--Burst Improvement
Time
Utterback'sCharacterizationof Product Development:_
First Stage:
Concentration
is on product innovation
until it becomes an established product
Second Stage: Concentration is on process improvement
Third Stage:
Burst improvements in product stimulated
Fourth Stage:
New technologies
by new requirements
take over; e.g., quartz watch, word processor,
and new technologies
refrigerator
Recommendation:
(1) Work hard to accomplish major burst in the current suboptimum approach, fine tuning it for more efficiency
in performance, cost, reliability, safety, operability, and scheduling.
(2) Pursue new technologies that can revolutionize vehicles.
Figure
4
2. Product
evolution
cycle.
The
results
presented
This was achieved
Overview
and Organization
in this report
characterize
and baseline
by systematically
process.
This
following
is a brief explanation
1.2.1
1.2 Report
overview
defining,
is intended
delineating,
to illustrate
of the various
that
method
via the
sections
of the report.
and goals
of this activity.
section
presents
the motivation
process
is explained
as well as the challenges.
The
briefly
characterized
and explained.
characterization
reflect
the potential
impact
1.2.2
Process
space
design
organization
processes.
of the design
of the
report.
The
scope
In addition,
of the effort
the complexity
is delineated,
of product
of the
and the process
is
is introduced
to
between
the
development
community.l
Overview
A top-level
description
transportation
system
of the design
(STS),
with compartmentalization
thumbnail
sketch
1.2.3
Utterback's
on the aerospace
functions
is presented
process
launch
is presented
vehicle
system
and allocation,
to delineate
concept
and
to show
subsystems,
and the technical
selection,
the connectivity
design
integration
preliminary
functions/discipline
process.
design,
Additionally,
and detailed
a
design.
Essentials
While
the design
considerations
that must
implicit
in the process,
essential
engineering
requirements;
formal
parameter
matrix
be asked
throughout
1.2.4
Design
process
be recognized
model
are
categories
criteria;
the design
there
implemented.
as follows:
sensitivities;
a design,
importance
considerations
uncertainties;
are also 11 essential
These
that we have
basis
of good
modes;
judgment;
turing,
and
decision
description
activity
are addressed.
informal
are developed
Then
integration
and probing
in this section.
the T-model
are defined.
investigated.
has
controls,
to the design
and engineering
via its work
characterization
(G&N),
In addition
gates
tests,
and
These
derived
and simulations;
questions
that should
process.
of this entire
and navigation
and others.
are subtle
"essentials."
constraints;
analyses,
First,
for technical
Finally,
breakdown
been
developed,
structures,
function
thermal,
planes,
a symbolic
propulsion,
model
aspects
of the
is introduced.
is developed
In
that
of design function planes
aerodynamics,
trajectory/
avionics,
the characterization
is also linked
important
integration
characterizes
technical
integration
and the design process. This model consists
associated
with the vehicle subsystems.
These design functions
are systems,
guidance
them
engineering;
of modelinJactivities;
failure
considerations
called
engineering
Description
framework
formal
and carefully
are of such
design
Process
technical
itself is key to evolving
but they
The main results
project
ated
vehicle
the key features
Introduction
This
this
the launch
and explaining
materials,
also includes
manufactheir associ-
tasks.
This model
to an existing,
detailed
discipline
structure
(WBS)
and N×N matrix
from
2. While
the basic
there
are some
detailed
of the model
aspects
reference
that
are still
being
1.2.5
Process
and
implementing
Improvement
It is thought that process
follow-on
efforts,
some ideas
categories
associated
improved
modeling
technologies
associated
with fine-tuning
tools,
Illustrations
The
with process
baseline
design
section.
An overview
Shuttle
conceptual
design
1.2.7
Distilled
Wisdom
This
of discipline
Shuttle
section
process
lessons
experienced
Examples
of the conceptual
are delineated
requirements
and criteria,
The categories
synthesis
and design,
design
these
process
activities
in this section.
designing
in
Some
for simplicity,
associated
with revolutionary
and interactive
information
and
learned
design
stage
to lessons
learned
and the results
remainder
references,
is given,
was
implemented
of this characterization
and an example
in the Saturn/
are given
is presented
were
distilled,
and they are presented
"What
Their
collective
wisdom
of the report
contains
conclusions,
and a bibliography.
of a survey
of experienced
herein, key ideas were noted. Then
was reviewed
to extract important
was taken to determine
years of experienceT"
in this work
of the application
in this
of the Space
process.
pertains
practitioners
The
the present
to investigate
analyses.
that is characterized
programs.
During the evolution
of the effort presented
baseline
characterization
effort, the process
resources,
improvements
are as follows:
and inte_ation
by fine-tuning
it is planned
of Process
and Space
glossary,
While
systems.
Apollo
many
can be achieved
technologies.
are compartmentalization/reintegration,
communications
1.2.6
improvement
revolutionary
in this section.
is the essence
is also presented
practitioners.
upon completion
of the
ideas. From these two
In addition,
a survey
design
based on your
of engineering
of
in this section.
recommendations,
three appendices
including
a
2.
The
illustrated
the
DESIGN
launch
vehicle
design
in figure
3. It can
be seen
system
attributes
design
process.
sion
efficiency,
related
process
challenges
that
the
dry
mass
efficiency,
on
cost
and
"-ilities."
As
uncertainties
and
interactions.
The
design
experience
to provide
insight
for
trading
same
knowledge
this
after
subsequent
design
judgments.
development
testing
and/or
The
in the
Mission Stalement:
mission
cost,
system
OVERVIEW
a challenge
the
to performance,
The
In addition,
presents
that
requirements
design.
PROCESS
statement
reliability,
designer
and
loss
can
be
of the
must
the
order.
is defined,
safety,
operability,
are high
along
loss
with
and
energy
falls
must
rely
upon
analyses,
testing,
within
and
among
the
various
challenges
is applied
to develop
design
and
associated
operations
stage
and
philosophies
judgments
may
lead
are
to operational
challenge
must
achieve
schedule
via
propul-
readiness
into
the
the
and
categories
simulations,
and
is
densities,
technology
management
process
base
This
the project
address
management,
seen,
highest
of
and
past
to achieve
the
best
methods
to support
eventually
assessed
after
constraints.
Insert a specified payload into a specified orbit to the required tolerances,
within cost reliability, operability safety, and schedule requirements
EngineeringChallenges:
Design and Management Considerations
Project Requirements
• High EnergyDensities
• Propulsion Efficiency
r.-...
• Dry Weight Efficiency
L Design To Achi
• Managing Losses
- Uncertainties
• Manufacturing Variables
• Environmental Variables
- Interactions
• Multidisciplinary
• Interfaces
• Operations
• Failureto Meet Technology
Readiness Level (TRL) Target
• Cost Reliability Operability
• Performance
• Cost
• Reliability
• Operability
• Safety
• Schedule
Figure
This
with
associated
report.
A
activities
section
thumbnail
of each
provides
challenges
an overview
and
connectivity.
of
the
sketch
design
3. STS
stage.
design
design--highest
of the main
The
process
order
features
details
will
sequence
challenge.
of the launch
vehicle
be
in subsequent
included
is provided
to show
design
the
process,
along
sections
of
ordering
of
the
main
2.1
The engineering
design
(1) Requirements
definition,
and (5) operations
(fig. 4).
Top-Level
process
(2) design,
Definition
Requirements
Characterization
has five major
areas of emphasis
(3) build
or buy),
(make
that flow
(4) system
in sequential
integration
order:
and verification,
i
"_
Design
Build
I
(Make/Buy)
L
Integration
and Verification
I
Syslem
Operations
Requirements
definition
Figure
4. Design
specifies
what
process/life-cycle
the product
flow.
is to do and how
well
it is to do it. It also
specifies constraints,
philosophy,
and criteria (e.g., margins, etc.). Therefore,
the design process starts with
the mission
statement
and requirements.
These are defined in terms of the requirements
of the orbital
characteristics
(orbit
requirements,
other requirements
testing,
and evaluation
program
Many
payload
as the design
controls
to meet
such as design
groups,
In conjunction
These
turbopump
requirements
ending
system. The process
technical
communications,
as constraints
progresses.
flow down of the process
an operational
and verification
have legal criteria
are called
interchange
meetings,
thus enabling
the design.
derived
cost (design,
include
development
requirements
which
requirements
before
such things
figure
design,
etc.,
and discipline
which
enhance
has
levied.
as geometry,
and programmatic
at the flight readiness
system,
development,
etc. NASA
that are contractually
requirements,
Finally,
requirements
and take many
operation;
to the mission
time,
may include
cut off or shut down.
system
boards,
These
with these mission
and constraints
works through
In addition
that must be met by the design.
temperatures
with a verified
to be delivered.
reliability,
reviews
impacts.
functions
life cycle),
are provided
and engine
all these
are also levied.
operations;
requirements
and discipline
etc.) and the payload
and constraints
size, and environmental
load relief
verified
altitude,
(DDT&E);
requirements
times additional
most design
evolve
inclination,
forms;
for example,
An STS must
be formally
4 illustrates
the top-level
review
(FRR),
thus providing
functions,
technical
technical
integration
working
and
In order
knowledge
for the design
are defined.
(2) Governmental
infrastructure
constitute
and
general
specialization.
Figure
specialization
on design.
capabilities
consist
(concept
identification),
iteration
loop between
of the figure.
These
the synthesis
that have
As
the design
and specialized
already
been
activity
example,
become
assessment
and tasks
For example,
The designer
a major
design
of these
three
areas
processes,
process.
The
into workable
units,
(2) synthesis
concept.
There
activity.
The
is a major
of the
of compartmentalization
is
Design
can thus start with SOA
of various
airfoil
the one that best fits the product
problem.
design
results
Industry
and
standardized
various joint concepts
and analysis techniques.
All these standards,
data bases,
are used for the initial synthesis process. The analysis and assessment
function then fine-tunes
Industry
• Design
• Manufacturing
of aerospace
manufacturing
the characteristics
can choose
specialization,
for the design
The heart of this approach
developed.
are
bases
and assessment
that have been developed.
joints
(1) Industrial
of the synthesized
processes
and programmatic
5 shows the influence
technologies,
the basis
and the analysis
specifications.
and demonstrated.
another
and
areas:
and knowledge
monographs,
of the hardware
and (3) analysis
produce
have been investigated
design.
block
The
by standards,
of (1) compartmentalization
the SOA knowledge
capabilities
is captured
of the state of the art (SOA)
units after the mission
exists in three
in the center
activities
into workable
information
which
The SOA
and take advantage
and (3)Academic
activities
under
efficiently
specialization,
the SOA
shown
design
to work
base, the STS must be compartmentalized
requirements
etc.,
process
academia
shapes
concept
have
and processes
and optimizes
Divide
• Compartmentalization
Capability
* Technology
i
ill /iiiiiii!ii!i
!i!ii!51
Inslilutesand
Government
• Knowledge
Base
• TestandLaunchFacilities
• Methodology
• Technology
• StateoftheArt
-Standards
-Monographs
-Technologies
-Manufacturing
Capabilities
• Advanced
Technology
Academia
Synthesize
•D= p..es
--
• Research
• Technology
B
S
_-
Figure
5. Influence
of aerospace
infrastructure
Analyze
and
Assess
and specialization
in design.
9
and,thus,resynthesizes
theproduct.(The iterationloop on the figure.)
of the
three
specializations,
Compartmentalization
infrastructure,
along
by industrial
thus cutting
discipline
complex
theories
codes
(CAM),
structural
are available,
codes,
synergistic
tunnels
including
the STS overall
and industry.
system,
starts
in figure
vehicle
(design
• Payload
interfaces
industrial
expertise
and
compartmentalization
is
research
labs.
Most
of the
along these discipline
lines. Discipline
and
analysis
more
efficient
(CAD)/computer
codes,
and massive
aided
as well
computing,
efforts.
manufactuerers
as many
others.
etc., not available
The three areas of specialization
in
produce
systems.
with the definition
6. These
of existing
thermal
of the top-level
are based on specilized
the first level of compartmentalization
• Launch
• Operations
process
cost.
design
are examples.
of future
at lower
(CFD),
for testing
test stands
to the design
as delineated
Typically,
facilities
engine
The compartmentalization
aided
advantage
product
in Government
penetration
of taking
quality
and academia
codes have evolved
fluid dynamics
specialized
critical
advantage
Government
technical
This approach
in a higher
practiced
computer
computational
and rocket
technologies
indepth
takes
and
computer
for
result
quality.
in universities
provides
also has many
Wind
can
specialization
and the corresponding
Discipline
Government
properly,
cost and increasing
lines as taught
compartmentalization
industry.
if used
systems
capabilities
that comprise
of Government
is composed
of the following.
for assembly,
mission
and build)
(accommodations)
systems
(hardware
and software
required
operations,
and
refurbishment).
Depending
defined
discussed
differently;
on the complexity
however,
later, each of these
the
systems
of the STS and the industrial
compartmentalization
process
has its own design,
specialization,
these
is essentially
the
manufacturing,
and verification
1.0
STS
I
2.0
Launch
Vehicle
Figure
10
6. Top-level
3.0
Payload
Interfaces
compartmentalization
4.0
Operations
Systems
of design
process.
systems
same.
can be
As will
processes.
be
The next step in the process
mentalization,
the requirements
decides
proportion
what
Several
are apportioned
and levying
is allocated
are available
for enhancing
techniques
Quality
function
deployment
task.
with
the customer's
of requirements.
to the three systems.
of the STS budget
subsystems.
It starts
is the allocation
(QFD)
and translates
For example,
top-level
requirement
allocation
accepted
them
to the
approach
into designable
attributes
the importance
of each,
providing
an indication
of priority.
The QFD process
in many
of the listings
in the bibliography;
therefore,
no further
discussion
tool to aid the allocation
experience
base
of the leader
process;
however,
and others
weak
pad affects
other facilities.
and can mainly
be treated
they must be engineered
The
launch
compartmentalization
vehicle
being
on into smaller
The same
on the
hardware/software
item a subsystem.
of designing
each
subsystem
middle
portion
subsystem
design
process
into a set of design
of design
manufacturing,
subsystem
into an integrated
(Note
into smaller
etc.; however,
down
tree,
then into a hierarchy
7.
Each
a second
second
type
functions.
These
design
functions
type
functions
of structures,
etc. The
products
of the design
functions
are the specifications
in the stack is the "system"
plane that integrates
subsystems,
there
by a single
will be an associated
designer,
making
needed
will
that corresponds
vary
from
the
for their
by a
subsystem
thermal,
to
avionics,
portions
the other design
of the
functions
to the stack.
stack. As we move
stack with each subsystem
use of handbooks,
as
divides
are represented
propulsion,
function
call the
of compartmentalization,
functions
on the tree has its own design
and so
we will generically
specific
for the subsystem
the
on the tree is a
of compartmentalization
design
with
of sub-subsystems,
design
(specification)
the
of the entities
of this discussion,
entails
7. This
continues
The
that each subsystem
can be designed
ization
of figure
are generally
(ICD's),
the
design
and
couplings
planes.
The top plane
on the judgment
etc. These
include
design.
in detail
QFD is a
documents
typically
but
function
systems
For purposes
on the
subsystem,
control
left side of figure
indicated
"stack"
It
some level of optimization.
into subsystems,
as indicated
item that must be designed.
process
via interface
of the hardware/software
hardware/software
The
is true of the payloads,
to achieve
compartmentalized
entities,
is described
draw
this
of the system.
here is warranted.
must
and
there are interactions/interfaces
between
the various
systems
to achieve overall balance. The vehicle affects the launch pad;
with allocations
and balanced
typically
systems
involved.
After the allocations
are completed,
that must be determined
and traded in order
the launch
allocation
STS
for accomplishing
weights
useful
management
to each of these.
is the most
wants
At this level of compart-
down
until we arrive
etc. At this point,
further
the tree
at parts that
compartmental-
is not necessary.)
A third
functions.
simulations
type
of compartmentalization
Disciplines
are technical
in support
areas
of the design
occurs
on each design
function
plane,
involving
discipline
of specialty
and expertise.
They
perform
analyses,
tests,
functions,
function
planes.
This third compartmentalization
function
plane,
there
arrive
at a design
is an iterative
(specification)
synthesis/analysis
whose
attributes
and
they
is indicated
activity
can be thought
of as residing
on the right side of figure
that draws
meet its allocated
and
on the design
7. On each design
on all the pertinent
disciplines
to
requirements.
11
Figure 7. Categories
12
of compartmentalization
of design
process.
Thus,thereare threetypesof compartmentalization--subsystem,
design
function.
design.
Each
Figure
compartmentalization
9 illustrates
to the right)
and their
reintegration
then results
These
integrating
main
the three
subsequent
concepts
reintegration
will be further
the compartmentalized
subject
address
with the launch
shown
are:
•
System
•
Aerodynamics
•
•
Trajectory/G&N
Control
•
Structures
•
Thermal
•
•
Propulsion
Avionics
•
Materials
•
•
Manufacturing
Others
The structures
content.
design
Also,
there
in categories
and discipline
downward
to the left). Completion
in section
design
function
system,
4. The
is a primary
characterization,
as shown
plane is expanded
expansion
the iterative
process
challenge
of the final
of technically
and constitutes
As the design
of performance,
to show
the decision
a
The comparisons
satisfying
of the stack
of design
the iterative
operability,
attributes
functions
as an example
gates
to converge
are the numerous
safety,
of these numerous
where
through
function
design
that reside
of the
on the
beginning
with requirements
and
and reintegrating
the discipline
activity
matures
Attributes
the design
8. The
on the right side of the figure
below
cost, reliability,
consider
on the left of figure
synthesis]analysis
with the requirements.
gate diagram
function
on a design
process,
measures
its attributes
with the requirements
means
satisfying
the summary
function
planes
is the system
are
of "goodness"
etc., and are related
all gates
specificaof the
one-for-one
are represented
decision
gate
on
on the
plane.
The top plane
allocation,
for the subsystem
entity
sented
by the stack
between
the design
and within
and explained
into a successful
is an additional
the requirements.
and compared
mentalization,
upward
(proceeding
system
design.
vehicle
function
to execute
with requirements.
design
the design
design
necessary
the decision
(proceeding
and discipline
the complete
of compartmentalization
plane is a flow diagram
which shows top-level
activities,
allotted
to that design function,
then compartmentalizing
tion that meets
assessed
function,
to constitute
of this report.
associated
functions
reintegration
types
expanded
parts
To further
plane. Each
architecture
requires
interconnected
in the total system
"stack"
plane
in turn
and reintegration
on the tree for which
is the information
function
the planes.
for the other planes.
The
planes
the stack corresponds.
flow that must
and the system
rectangular
Its product
vertical
occur
plane
conduits
among
is shown,
plane.
It provides
the compart-
then is the design
specification
A major
feature
the planes.
Critical
as well as informal
with arrows
pointing
of the process
repre-
formal
feedback
feedback
between
downward
represent
the
13
System
Aerodynamics
.........
Trajectory/G&N
Control
Structures
Thermal
Propulsion
Avionics
Materials
.".:i
Manufacturing
Other
Figure
8. Illustration
flowdown
of requirement
ing upward
represents
system
plane.
upward
and downward
These
tion also occurs
The
of design
allocations,
the upward
conduits
flow
amount
formal
integration.
The circular
the design
conduit
with arrows
pointing
the process
will be further
(designated
IxI matrix)
to address
to address
information
flow
in the launch
vehicle
flow
throughout
Two types
information
among
of matrices
will be used:
flow among
the subsystems
design
design/analysis
functions
process
and
disciplines.
has
been
point-
plane
disciplines.
flow matrices.
with arrows
function
the various
matrix
integration
from
plane within and among
matrix
14
attributes
column
function
4, using
flow
The vertical
example.
the design
section
information
and approach.
plane
among
of information
information
stack with structures
of the design
informal
on the design function
large
architecture,
represent
represents
function
planes.
Informal
to the
both
integra-
characterized
an interface
in
information
on the tree, and an NxN
Material
developed
related
to the
by MSFC 2 that
System
Def
nilion_"-"_
Launch
Vehicle
_
1SubsystemSsystem
Intolj
Reintegratlon
ofI
ii
I
Reintegralion
of
Into
_
Subsystems_
Compartmentalization,.,
Subsystems J
I
J IntoSub"System"
DesignFunctionsI
Compartme!tahzatlon
I
Designln_Onc
i,on:
ii
t
DisciplinesInto
Design
Reintegration
Functons
of I
_
FDnecS_igonn
s
_1_
I
1
Compartmentalization] _ I
Into
Disciplines
J
I
"
Disciplines
ExampleDiscipline Functions
ExampleDesignFunctions
(DevelopSpecifications for
Hardware and Software)
(Perform Analyses, Tests,and Simulations)
•
•
•
•
•
•
System
Aerodynamics Design
Trajectory
GN&C
Structures
Thermal Protection System (TPS)
and Thermal Control Systems (TCS)
• Propulsion
• Avionics
• Materials
• Manufacturing
• Facilitiesand Ground Support
Equipment(GSE)
• Operations Software
• Other Systems; e.g.,
- Pyrotechnics
- RecoverySubsystem
- Life Support
- Etc.
• System
• Structures (Example ExpandedBelow*)
• Aerodynamics
• Control
• G&lkl
• Trajectory and Flight Mechanics
• Materials
• Manufacturing
• Testing
• Simulation
• Mission Analysis
• Propulsion
• Thermal
• Life Support
* Categoriesof Discipline Tasks:
• Structures
- Dynamics
- Stress
- Durability
- Stability
- Vibroacoustics
The Discipline FunctionsEnablethe Design Functions
Figure
addresses
discipline
inputs
matrix
mentioned
above,
process
description
given
9. Design
process
and outputs,
discipline
compartmentalization
tasks,
flow charts,
and products
and reintegration.
of the design
and task definitions.
........
process.
These
details
This includes
the N×N
are integrated
into the
in this document.
15
Figure
exchanges,
10 is another
and balancing.
ing it to include
design
This document
of illustrating
all aspects
would
is shown
in figure
interactions
the structural
way
This figure
subsystem.
will probe
illustrates
cloud
the complexity
of design/discipline
some (but not all) aspects
the visualization
11. This figure
Technical
integration
further
into its definition.
process.
includes
is a complex
some
Another
details
process,
interactions,
of design
interactions.
example
of visualization
of the internal
as this top-level
Technology
data
Expandof
process
flow for
discussion
shows.
i
Vibration
Structural
Integrity
' - Natural
*"4, - Operational
i
Dynamics
......
Verification
- Analysis
- Test
- Simulation
- FlightEval.
Structural
Design
Fluids
- Margins
- Performance
Control
1
Thermal
orTPS
Operations
- Constraints
- Limit Indicator
- ModelUpdate
ECLS
Design
Atmosphere
,_
In summary,
the process
then to the compartmentalization
design
is accomplished
analysis, test, and simulation.
A schematic
of the interaction
16
(integration)
discussion
10. Design/discipline
starts
with
requirements
of the overall
by the design
by manufacturing/assembly/checkout.
process
Detailed
Figure
system
interactions.
definition,
moves
by comprising
functions,
supported
The design
as built must be verified
Operational
procedures
of the design functions
Criteria/Procedures
DesignStandards/
to top-level
systems
by the discipline
system
by subsystems,
functions.
Design
studies,
etc. Their
is followed
to meet the requirements
through
are derived from the design and verification
process.
and discipline
functions
is depicted in figure 12. The
is very complex
and requires
focused
of these aspects is given in section 4.
communication,
both formal
and
informal.
Project
Requirements
...............................
Interaction
.......................
,_.'._
Design
|
_ IStandards/Criteria_
Analysis
Thermal
Design
Environments
- Aero
Flow
Heating
- Propulsion
- Acoustics
- Vibration
Natural
l ec
gy/
-Analysis
Heat
__
_1- Passive
Transfer
I- ACtive
- Definition _
Structural
Analysis
- Loads
- Vibroacoustics
- Stress
- Fatique
- Fracture
........................
_-
Design
System
Subsystems
Elements
Control
Logic/
Sensors/
Effectors/
Computers
Verification
Pads
Operations I
- Support
I
- Constraints I
QesignLoo_
.....................
I Codes/Procedures _
Figure
Requirements
Mission
Conceptual
Design
11. Structural
I
design
process
flow.
CompartmentalizationlReintegration
[
syst°m]J
$
Preliminary
Design
$
Detailed
Design
Manufacturing
Subsystem
Structures j
• Propulsion
*
_
Disciplines
Design
!unctions
System Integration
and Verification
Etc.
Figure 12. Design process flow.
17
2.2
ments.
The design
process
The leader
is responsible
sibilities
are reflected
constant
communication
essential
functions.
Essential
Functions
Engineering
must be focused
on achieving
for managing
on the top-level
of Engineering
• Obtaining
and Assessing
• Synthesizing
Concepts
the best total system
the design
system
with members
the System
design
of the design
process,
design
for engineering
function
plane,
and entail
team.
Engineering
to meet
the require-
the system.
His respon-
wide-ranging
the system
involves
judgment
and
the following
the System
Requirements
and Designs
• Compartmentalization
• Technical
Integration
• Risk Management,
• Trading
including
Concepts
• Manufacturing,
Integrating,
• Developing
There
the Flight
are numerous
tools,
there
Operations
tools
used
Rules
generation
tools,
• Synthesis-aiding
tools,
such as TRIZ
design
programs
the following.
Typical
Tool Categories
the Design
and Constraints.
to accomplish
• Requirements
include
these
specific
essential
functions.
to the design
process.
In addition
Categories
to generic
of such tools
such as QFD
programs
• Computer-aided
optimization
• Engineering
tools
analysis
• Manufacturing
process
• Engineering
test
• Sensitivity
analysis
simulation
tools
• Cost analysis
• Decision
tools for trade
studies
• Risk management
tools,
including
• Classical
engineering
systems
management,
• Design
• Integrated
18
and Verifying
that are more
• Design
Risks
and Designs
are tools
• Sizing
Development
and Balancing
• Downselecting
management
Technology
and verification
FMEA,
tools,
fault trees,
including
plan
reviews
Information
and Communication
and risk/consequence
requirements
System.
flowdown,
analysis
WBS,
configuration
2.3
2.3.1.
This section
provides
Conceptual
Design
2.3.1.1
an overview
Conceptual
Design
are defined
and understood,
feasible
determined
via trade and sensitivity
risk, cost, reliability,
plans
and other
2.3.1.2
Definition.
After
alternative
top-level
Along
operability,
etc. Selection
Activities.
design,
Conceptual
the basic
mission
Sketch
of the process
studies.
safety,
of conceptual
a. Identify
schedule,
schedule,
documents,
At the completion
Thumbnail
the mission
refined
system
divided
statement,
concepts
by design
stages.
requirements,
are defined
there
and constraints
and their attributes
are supporting
studies
requirements,
facility/GSE
concepts,
are also developed
to evaluate
the alternative
is a review
design
sequence,
with each concept
criteria
there
of Process
follows
requirements
called
the system
a process
(mission
definition
with the following
definition,
pounds
related
to
TRL, project
review
concepts.
(SDR).
steps:
of payload
to orbit,
cost,
etc.)
b. At the top level,
define
potential
staging,
reusability,
and
avionics,
and thermal
systems).
concepts
broad
to meet
definitions
requirements
of propulsion
c. Define
evaluation
metrics.
d. Perform
top-level
sizing
and analysis
of the concepts.
estimates
of geometry,
mass, environments,
(1)
Preliminary
(2) Trajectory
and performance
(3) Induced
environment
(4) Top-level
sensitivity
(5) Margin
determination
(6)
Determination
(7)
Risk assessment
(8)
Trade
e. Develop
selection
overall
system(s),
architecture,
structural
and propulsion
systems,
characteristics
definition
definition
study
(example:
necessary
of performance,
and technology
and balance
(includes
among
criteria
to envelope
cost,
versus
dry weight
margin)
uncertainties
and other
development
alternatives
and select
dry weight
attributes
needs
to improve
attributes
and risks
top contenders.
19
f. Modify
the contending
g. Repeat
the above
h. Downselect
concepts
process
to remaining
based
with more
in-depth
candidate
concepts.
i. Modify
the remaining
candidate
j.
Modify
requirements
(if data indicate).
k. Continue
to repeat
1. Define
the leading
on evaluation
concepts
the above
process
concepts
with general
data.
evaluation.
based
on evaluation;
until clear,
leading
configuration
add new ones
concepts
emerge.
definition,
sensitivity
(if data indicate).
data, and induced
environments.
2.3.1.3
feasible
constraints
above
Products
alternative
of Conceptual
concepts
with acceptable
in the definition.
The concept
tive, sound
can be integrated
margins
In some
selection
engineering
output of this program
the subsequent
stages,
Preliminary
and Detail
Preliminary
and detail
increased
set of
requirements,
and
and risk. In addition,
there
are additional
supporting
data as mentioned
there may be only one concept
leading
to selection
for overall
sizing;
by the respective
have
levels
requires
of invendesign
the operational
for technical
soundness.
of penetration,
detail,
and
The tasks
and scope
for
as the
Design
design
follow
and the results
differ
significantly.
Preliminary
Design
Definition.
is capable
the same general
from the conceptual
approach;
The purpose
design
i.e., the steps;
of preliminary
design
of meeting
requirements.
To achieve
these results,
the significant
subsystems
and their requirements
of trade
the requirements,
and sensitivity
is increased
through
safety,
operability,
schedule,
risk, cost, reliability,
interactions,
requirements/concepts
studies
pertinent
are defined
tests,
top-level
and the fidelity
from conceptual
completion
of preliminary
design,
design,
which
and TRL
are refined
of the project
plans and documents
that
of the architecture
and preliminary
is
The depth
tests, and simulations.
plans,
the above procedure
there is a review
the depth
assurance
are defined.
verification
nary design can occur in iterations as concepts are downselected
remains. This concept then goes to detail design. In the situation
nary design
greater
the fidelity
analyses,
however,
is to determine
stage is the best and to provide
and refined; in addition,
Interfaces,
requirements
and is verified.
concepts
of penetration
20
a small cadre
in the early part of conceptual
however,
disciplines
increasing
selected.
therefore
who carry out the tasks. The tasks
however,
2.3.2.
the concept
are a reduced
statement,
into one program
matures
2.3.2.1
design
the mission
quantification
program
of the selected
of conceptual
satisfy
must be assessed
program
of penetration
The products
which
attributes
situations
specialists
together
Design.
that have
Then
and reassessed.
facility
and GSE
is updated.
Prelimi-
after each iteration until the best concept
where only one concept goes to prelimi-
is still utilized
called the preliminary
but for a single
concept.
design
(PDR).
review
At the
2.3.2.2
cations
manufactured
reliability,
mission
called
Detail
Design
for all the hardware
and
Definition.
The purpose
of detail
and
of the fully
analyzed,
operated
within
safety, operability,
statement,
software
schedule,
requirements,
the critical
design
2.3.2.3
Activities.
Preliminary
design
is in-depth
and finalizes
cost
flown
with
and technology
and constraints.
review
operates
and
design
is to provide
tested,
an acceptable
readiness
risk.
attributes
At the completion
drawings
and simulated
The
and specifi-
STS
that can be
performance,
of this system
cost,
must satisfy
of detail
design,
there
same
general
approach
the
is a review
(CDR).
Preliminary
and
at less depth
because
all the design
trades
detail
design
follow
the analysis
the
and test data have not matured.
and the configuration
for production.
The steps
(steps).
Detail
design
are in general
the following:
a. Using
(I)
the database
and the concept
Delineating
the major
(2) Allocating
requirements,
design
(1) Define
function
in more
elements,
constraints,
and discipline
detail
mass properties,
(2)
subsystems,
apportion
the design
components,
task by first-
etc.
etc., to these entities
and their associated
functions.
b. Start the design
(Note:
selected,
process
the data base
aerodynamics,
Steps b(2) through
for each major
required
thermal,
subsystem.
for the discipline
task. Data
materials
properties,
etc.
bases
b(7)
are examples
pertaining
to structure
design.)
Run the trajectory/performance
analysis.
Provide
data to other
disciplines.
(3) Using
the baseline
control
trajectory,
requirements,
Conduct
structural
the loads analysis
environments.
(5)
Determine
the thermal
stress
Durability
(7) Determine
(8) Perform
analysis
and its subsets
of strength,
sensitivities
and margins.
design
analysis
the control
loads, etc.
fracture
studies
using
environments,
among
(9) Assess risks and technology
(10) Reintegrate
definition
also includes
trade
the control
determining
the control
logic,
and responses.
(4)
(6) Perform
conduct
include
functions
results,
stability,
determining
deflections,
the induced
and durability.
and fatigue.
alternatives.
development
and subsystems
plan.
at each level.
21
(11)
Perform
risk assessments
and trade
c. Modify
the design
based
d. Repeat
the process
in more depth.
The above
sequence
overviews
are concurrent
parallel
design.
There
• Thermal
protection
studies,
and balance
design
at each integrated
level.
on the results.
trajectory/performance
design
and thermal
activities
design,
for other
some controls
subsystems
design,
and design
and structural
functions,
such as:
and also interact
with the
control
• Manufacturing
• Avionics
design
•
Propulsion
•
Other
systems
These
subsystems
process
of other
Two major
the competing
f_om straightforward
design
alternatives.
assessments
are done
2.3.2.4
coupled
element
for each
of launch
vehicles,
A balance
range
to
in com-
out the differences
trade
must
the best design
alternatives
risks. Trades
that drive
studies
in
are usually
be achieved
also requires
risks must be actively
managed
throughout
Failure
mode
design
process.
alternative.
required,
design
among
balancing
the
among
disciplines.
A technology
along
development.
analyses
assessment
with the risk associated
Active
risk
and risk/consequence
for each
design
with maturing
alternative
the technologies
level.
Products
of Preliminary
Design.
that has attributes that satisfy the mission
margins
and risk. The margins
at the completion
baseline
studies
of the
design
development
among
and managing
process.
Achieving
and technical
concept
those
sequence
are (1) trading
trade
nature
part of the design
cost, and schedule
is an essential
process
to detailed
etc., of the design.
functions,
assessment
technology
etc.
and (2) assessing
decisions
of the strongly
a significant
design
the design
of the design,
judgment
operability,
Technical,
functions
that permeate
Because
cost, performance,
to an acceptable
have their own design
aspects
and constitute
identifies
and design
activities
plexity
the subsystems,
recovery,
subsystems.
balance
numerous
such as pyrotechnics,
for detail design.
The
major
product
of preliminary
design
is a single
statement,
requirements,
and constraints
with acceptable
and risks at the completion
of preliminary
design
be reduced
of conceptual
design.
In addition,
all system
The
concept
support,
at the completion
manufacturing,
should
of preliminary
design
test, and operations
from
is the
requirements
are also defined.
2.3.2.5
Products
of Detail
Design.
The products
of detail
the hardware
and software pertaining
to STS. These descriptions
The attributes associated with the system must satisfy the mission
with acceptable
margins
products
plans for final development,
22
include
and risk. At this point
the margins
manufacturing,
design
are engineering
descriptions
of
are drawings, specifications,
plans, etc.
statement, requirements,
and constraints
and risks should be at a minimum.
verification,
and operations.
Additional
2.3.3
Successive
Refinement.
order
to provide
During
schedule
process,
discipline
and
order
while
demonstrating
idea
of successive
refinement
adherence.
convergence
there
the design
The
to a concept
is considerable
there
are various
(see fig. 13 and references
uncertainty
(i.e., risk)
the knowledge
base can be very limited.
in regard
to satisfying
all the requirements
decisions
is deeper
are made
and deeper.
that eliminate
certain
iteratively
while
of knowledge,
decisions
can be made
the downselect
was achieved
preliminary
design
and the downselect
stage.
is determined
government
process
are studied
and assessed
information
are iterative,
about
continues,
Eventually,
options
the knowledge
base
through
this successive
There
have
"_
been
and then
is refined
refinement
projects
stage,
and there
are others
where
agencies
where
protoflight
hardware
cost,
In
and on each cycle
the concept
As concepts are continuously refined and uncertainty
is reduced, choices among concepts can be madewith
confidence.
NewonesAdded/
is first initiated,
concepts
studies
ConceptGeneration
CC
on
proceeds,
These
Decisions at every step require that new information
be developed to mature the concepts.
Reduced _
attention
feasibility.
ProductDesign
Specifications
(PDS)
Apply Concepl
Generation (CG)
and
and cost
Physical realization of a system results from a
succession of decisions among alternativeconcepts.
InitialNumber"_
of ConceptsBased/"
in
cost
schedule,
FronbendDesignWork
on PDS ¢
InitialNumber\
where
it was late in the
and production
is developed,
schedule.
Concept selection consists of the defining and
understanding alternative concepts and implementing
decisions that lead to downselecting one concept.
Further _
_
X
by focusing
the design
to the best concept.
design
into stages
with
technical,
As the design
to downselect
emphasis
divided
maturity
of the actual function,
ApplyControlled
Convergence(CC)
CC
provide
has been
technical
by comparison
_.__I
CG
with
is decreased.
in the conceptual
are other
adds
As the project
options.
the uncertainty
There
evolving
and constraints.
The results
and increased
The process
3 and 4). When
associated
addition,
the penetration
stages.
Reduction(FR)"_
Further/
-'V
CG
CC
(SeeReference:3)
[SeeReference4)
Iterate/penetrate Until the Degree of Uncertaintyand Concept
Discrlminalors WarrantMovingto Next DesignPhase ................
Figure
13. Successive
b
refinement.
23
3. ESSENTIALS
Before
presenting
applicable
to each
implicit
in the process,
the methodology
design
function
in detail,
and program
The process
described
augment
is the individual
or collective
geared
on historical
maximum.
sensitivities
the human
as (1) sound
physical
3.2
Constraints
and evaluated,
the maximum
Manned
constraints
constraints
and technical
the design
procedures,
judgment.
In the end it
process
for judgment,
Most
an acceleration
that occur in a variety
3.3
Requirements
additional
on the
Therefore,
it is
are initially
Shuttle
is constrained
constraint
of 3.15
G's
evolve, and changes are made based on the effects of
are much more difficult to implement,
because they
interactions
Derived
be based
constraints
for the Space
on
of good
and (3) communica-
acceptance.
levies
is based
the basis
must
alter a design.
pressure
flight
(design
they greatly
before
dynamic
The methodology
and logic
as a basis
because
and quantified
815 psf dispersed.
have both programmatic
Guidelines,
decisions.
principles
experience
and
not dogma.
mind, the human
of the data and logic. Furthermore,
As the studies/design
progress,
and trades. Cost and schedule
During
on methodology,
replace
in key design
be understood
and
"essentials."
the validity
data. For example,
to 650 psf nominal
and depends
(2) depth of engineering
communications.
that their effects
that are
are subtle
of Good Engineering
but can never
must be defined
essentials
them
that results
can be characterized
based
that we have called
some
sometimes
judgment
engineering
The constraints
to understand
considerations
to question
method
physics of the problem),
tions, communications,
Basis
is logical
the process
the scientific
imperative
These
but they are of such importance
3.1
and criteria
it is necessary
stage.
requirements
evolve.
These
of ways.
derived
requirements
are neces-
sary to balance
the system and are determined
through basic trade studies where top-level
requirements
must be met. These are usually the basis of how the system is flown and/or how it is made to work.
Examples
I-load
of derived
updates,
implemented;
assessed.
requirements
are load-relief
monthly
ground
wind
operational
constraints,
however,
they
in general
introduce
additional
Formal
Design
3.4
In the design
are the formalized
ments,
control,
process,
design
the design
criteria
to all NASA
Headquarters
derived
failure
biasing,
requirements
are evolved
and
that must
be identified
and
modes
requirements
projects.
These
and at the various
and constraints.
Among
these
are in the form
of formal
docu-
Centers.
The Center-levied
and requirements
can be tailored for individual
projects; however, the NASA Headquarters
not be violated
in intent. The discipline
specialists
develop most of these Center-associated
24
day-of-launch
Criteria
must meet numerous
applicable
and they exist at both NASA
etc. Typically,
mean-wind
criteria
criteria
criteria
must
even
though they may be listed in the systems requirements.
function is to determine
what criteria will be imposed
design
function
and the project
criteria
delineate
the various
discipline
criteria
apply
design
requirements,
etc. Each
individual
discipline
functions
are responsible
Many
verification
gram
stages
including
provides
discipline
endurance,
model
criteria
met or waivers
developed.
For example,
matures,
model
this factor
correlation
requires
an indentured
loads
the factor
which
requires
of various
parts
is specified
usage,
to processing,
criteria.
It depends
and
design
margins
more
characteristics.
process
without
exist for flutter,
using
The thermal
having
specific
etc., and are spelled
is focused
of these
as the project
the dynamic
survey
and fracture
factor.
There
for each
Most
set of
and gain margins,
industries
stability
design
have
also on the subject.
which
criteria;
as
in the analysis
discipline,
by the various
the mantle
and not the detailed
a comparable
pres-
There is an old but very good
good books
project
critical
Proof
has a less rigid set of
on conservatism
for design.
are many
have
discipline
aerodynamic
documents.
as guidelines
assessment
(NDE).
such as phase
and can be considered
process
Materials
depends
of pro-
this list a fracture
evaluation
The control
guidelines
disciplines
From
and nondestructive
criteria
products
on the design
on loads;
test and when
uses a 1.5 factor
In the
as well as criteria.
for
and must be
mainly
out procedures
formal
as a function
strength
out in the NASA
have
approaches
function
defined.
spelling
This document
1. The
Structures
factors
discipline
manuals
of successful
design
design
margins
that can be applied
3 says that development
the individual
as well as detailed
of the modal
established
monographs
to development
levels
documentation,
uncertainty
with the proof
design
critical
The main
in the structures
to characterization.
of NASA
Total Design
update,
initially
analysis
along
upon judgment
for each.
matrix,
however,
that all parts have been analyzed.
from material
requirements/
Also at the system
functions.
are defined
gates
analysis
becomes
fracture
criteria,
well as response
model
very formal
parts list to ensure
parts list is developed
sure testing
factors
may drop to 1.25. At the completion
is finalized,
maturity.
requirements;
these
required
for the verification
exist for use by the design
etc. Safety
become
maturity
First,
and implementation.
correlation,
etc. These
needs.
the level of project
the requirements
criteria
maturity,
specific
of project
input to verification
stability,
(test and analysis),
for their
and the levels
for their development
specialized
for strength,
the criteria
at each stage but recognize
are the verification
criteria
to tailor
One of the main activities
of the system design
on the design. It is very important
for the system
disciplines
envelops
however,
set
design
Pugh in
is very
the project.
they are very
important.
3.5
Throughout
attributes
the vehicle
are characterized
Categories
design
of Modeling/Activities
and operations
by descriptions
or models
processes,
of varying
the vehicle
fidelity.
performance
At today's
possible to have
tions. Likewise,
one single model
it is not possible
that describes
in full fidelity all of the vehicle constituents
to address total vehicle design as a single comprehensive
analysis
activity.
In the category
of vehicle
sets of descriptions
and activities:
.
performance
and physical
A generalized
description
directed
toward
overall
of the vehicle that is evolved
vehicle
performance.
This
performance,
and overall
load cycles,
vehicle
design
attributes,
through
category
for ascent
and
physical
state of the art, it is not
there
and interacsynthesis/
are three
synthesis/analysis
encompasses
parallel
activities
trajectory/
and return.
25
.
o
Discipline-specific
descriptions
tions. This set of models feeds
in fidelity
as the design
matures
and additional
Specialized
descriptions
and
synthesis/analysis
interactive
aspects
of the vehicle,
issues are addressed
The
design
than
category
such as flutter,
pogo,
from the generalized
description
is the "backbone"
Upon
entering
the operations
description
to serve
as a basis
those
related
there
is a second
associated
with
to constraints
vehicle
but could
cost,
and schedule),
the means
to assess
flowing
tions of the design
stage,
a less-detailed
of models
include
that must
and
and effective
functions
accomplish
by formulating
the analysis
uses a model
known
about
the system.
These
because
assumptions
the modeling
Engineering
judgment
on experience.
These
their tasks
testing.
The testing
has similar
to reduce
many
of the parts
process
cost,
etc., only the essentials
are mass
tions. As in analysis,
regarding
simulated.
engineering
what
are subject
In summary,
a successful
applying
proper
assumptions,
are tested.
based on experience
depends
upon
and producing
-ilities,
analysis,
founda-
test, and simudescription
and
In
and what
Many
errors
is
occur
database
is the anchor
and applying
assumptions
to
by benchmarking
methods
and
be duplicated.
In
cannot
For example,
constraints
dictate
in dynamic
these
for
testing
approxima-
and the evolving
databases
critical
combined
environments
are to be
as analysis
and test.
the discipline
functions
understanding
physical
and what
to the same considerations
design
the database
and technical
is to be tested
are essential
and revised.
The evolving
be validated
of the hardware
are
are associated
from experience
The actual flight environment
Programmatic
judgment
hardware
Simulations
principles,
limitations.
models
associated
or a mathematical
derived
challenged
from
should
the
of the system nor of the natural
of the plant and the environments.
and are not challenged.
in drawing
from
activities.
results
using
equations
on a set of assumptions
models
the
functions
must produce correct and
herein, it can be no better than the
discipline
describing
must be constantly
sacred
in developmental
order
26
assumptions
are considered
process.
is based
based
allow
are in a general
models
design
Test, and Simulation
starts
These
of associated
Analyses,
The discipline
the analysis
They
and other
this category
process.
These
operations,
and manage
correct
is extracted
attributes.
requirements.
safety,
in fidelity
also be developed.
physical
some ancillary
cost, reliability,
it. Consequently,
other words,
applied.
etc. These
constraints.
of the plant. This model can never exactly describe the response
induced
environments.
Therefore,
the model is an approximation
assumptions
and docking,
description
operational
performance
within
For example,
verified
to specific
with their design consequences
It increases
To design a successful
launch vehicle, the design and discipline
technical
results. While technical
integration
is emphasized
the models
are applicable
rendezvous
description
of the design.
for executing
category
3.6
information
that
throughout
and they provide
lations.
activities
generalized
with risk (technical,
effective
and tests are performed.
initially
In addition,
other
separately
analyses
being fed into the generalized
description.
(The generalized
description
should
"headroom"
for the accommodation
of the specialized
interactive
aspects.)
process.
generalized
that are developed
from discipline
analyses, tests, and simulaits information
to the other two sets. The descriptions
increase
accurate
results.
is the basis for
3.7
Each design
Initially,
Parameter
and discipline
they are based
function
on engineering
Matrix
and Uncertainties
must define
judgment.
and quantify
all parameters
As tests are run and analyses
and their uncertainties.
refined,
the bands
of uncer-
tainty are reduced. In general these uncertainties
are defined with some statistical
measure,
e.g. 3-sigma,
level relative to a nominal or mean. When possible, a distribution
is defined. Also, procedures
for proper
application
enough
of these uncertainties
to develop
conservatism
is avoided.
ing Group
(AFSIG)
flight
phase
serve
as guidelines,
approximately
methods
The
response
analyses,
the sensitivity,
for each
of the system
simulations,
the tougher
Failure
failure
instance
modes
modes
and its sensitivities
or tests; however,
the design
must
design
routinely
assess
and
assessed
using
specified
must
limits,
eliminate
etc.
or mitigate
factors
of safety
design
function.
The assessment
the structural
design,
by the system
logic diagram.
results.
This
consequence
which
consequences.
This
and hazards
analysis.
system
relates
process
In the final analysis
Structures
and
plane.The
or Why
Things
structures
failure
modes.
program
trends
history
can
are toward
more
This can be accomplished
through
analyses.
are two ways
to identify
and
design
functions
relative
plane
designers
and
For
stability,
consists
The higher
but from
failure
the structural
capability
potential
failure
systems
perspective.
put into some
using
and effects
analysis
act between
Fail Down 5 says:
wanted
"All structures
uncertainties,
(FMEA),
and unwanted
modes
to
are defined
by
This
is
activity
tree or cascading
and the trade study
with risk versus
sensitivities,
risks, and
critical
list (CIL),
items
characteristics.
will be broken
are
with respect
modes
formal
for
analysts
that are specific
and impact
modes
stress
structural
data are used to assess the failure modes
using
engineering
judgment
augmented
failure
In the
and others
the
are usually
modes.
to criteria,
example,
of comparing
modes
failure
endurance,
In the second,
specialists,
this is a balancing
Don't
the
to quantification
utilizes
there
margin.
failure
The uncertainty/sensitivity
assessment
is made
logic
prior
Future
Modes
for strength,
limit to determine
of discipline,
for each
Although
project.
accomplished
by discipline
On
to the design
orchestrated
Work-
matrix
be determined.
it is usually
Classically,
and assessed
the structures
a team
Integration
problem.
be identified.
are defined
various
new
Flight
uncertainties
Sensitivities
3.9 Failure
first,
the Ascent
that unneeded
of design.
3.8
through
and assure
the parameter
and procedures.
be repeated
are the only ones knowledgeable
the assumptions
developing
philosophy
must
specialists
stages of the Space Shuttle,
4 months
with the analysis/test
the process
The discipline
job is to question
In the early design
spent
along
probabilistic
are developed.
this data. Management's
Gordon
or destroyed
in
in the end.
Just as all people will die in the end. It is the purpose
of medicine
and engineering
to postpone
these
occurrences
for a decent interval: the question is: What is to be regarded
as a decent interval?"
Pye in The
Nature
of Design 6 discusses
problems
dealing
capable
of producing
the source
of problems
with the manifestation
change
is made
Things
are always
changes,
changes
by the passage
together.
and transfer
in things;
of energy
They
and their compromises.
of energy.
more
and a result
exactly,
the source
of
He says: "Any of these
forms
of energy
is
redistribution
Now whenever
a
is left, this event
do not exist separately
He talks about
of matter.
takes
and they cannot
place
in a group
act separately.
When
of things.
you put
27
energyinto a system,you canneverchoosewhatkind of changesshall takeplaceandwhatresultsshall
remain.All youcando, andthatonly within limits, is to regulatetheamountsof thevariouschanges.This
you do by design."He talks aboutthe compromisesin the "design for failures." "The requirementsfor
designconflict andcannotbe reconciled.All designfor devicesareto somedegreefailures."The designer
or hisclienthasto chooseto whatdegreeandwherethereshallbefailure.It is importantin thisprocessthat
engineershavea networkof specialiststhatcanbe calleduponfor understandingtheseproblems.
3.10
Good
engineering
gained
through
insights
qualitative
assessment.
comparisons
based
upon
using
judgment
balanced
Many
it is hard
to quantify
times
into play
which
aspects
of available
technical
success.
In fact, detail
The question
Typical
that
design
always
process.
into a subsystem
and
First,
relative
the compartmentalization
or sub-subsystem
industrial
is a judgment
specialization.
Second,
are generally
data. Third,
many
desirable
technical
refinements
some parts of the decision
and test conditions
to be within
some
eventually
can be quantified,
most
calls.
acceptable
become
the
made
must
are also judgment
be
become
risk that ensures
eventual
of managing
risk since
a process
"How
Probing
Questions
does management
In general
the job is done correctly,
and when
this is accomplished
ensure
through
of questions.
meet
requirements
with adequate
considering
analyses/tests/simulations
interdisciplinary
• Have
issues
and concerns
These
questions
technical
been
margins
been completed
asking
a series
integration
adequately
identified
do
lead
to the general
question,
"How
the following
questions
offer assistance:
• Define
and explain
ground
and assumptions.
was your
• What
comparative
analysis
method?
analyses,
How
simulations,
fidelity?
and dispositioned?
for which
• What
and
been done?
a judgment
rules
uncertainties
to the appropriate
do I determine
(Method)
28
cases,
risk, etc.)
and operations
arises,
all discipline
• Has adequate
usually
in these
are--
• Does the design
sensitivities?
• Have
or
tuned.
it is completed?"
questions
on
schedule,
are targeted
3.11
they know
however,
is based
a quantitative
(costs,
test configurations,
judgments
are so finely
Judgment
up with either
issues
risks, etc. Although
test options,
the decision;
of the components
in the presence
priorities,
process.
be backed
of the design
can be lumped
and complexity
Finally,
STS systems
in many
components
and programmatic
Fourth,
to the design
it should
the decision.
performance
against
a judgment.
flight
possible
the coupling
between
essential
Whenever
comes
of deciding
balance
is a critical
experience.
can be used to support
Judgment
process
judgment
Judgments
was it benchmarked?
and tests have
been done?
adequacy?"
The
answer
is
• Whataffectsyour system?What is it sensitiveto? Have
the interactions
• What
does your system
interfaces?
• What
concerns
• What
affect?
Have
you worked
do you have with the design
these
(or analysis/test
been
considered?
process)?
(Results)
trends/patterns
are present?
• Are they consistent?
Explainable?
• What
and the basis
are the margins
• Can the observed
characteristics
How does one explain
• Does
for the margins?
be explained
using a simple
analogy?
Using
a free body diagram?
the load paths?
it pass "the physics
of the problem"
check?
(Specialist)
•
What
is the engineer's
•
What
is the specialist's
track record?
•
What
is your specialist
comfort
J.R. Thompson
understanding
told Bob Ryan
At the time, J.R. Thompson
Project
of the uncertainties?
level?
the following
was MSFC's
Chief
story
that gives
insight
Engineer
following
his tenure
as the Space
to solve
some
problems
to get the first Shuttle flight off (had slipped at the time more than 1 year), Bob Ryan
talk to him about dynamic
issues that needed to be resolved
through
redesign.
He said, "Those
problems
imposing
scared
stringent
successfully.
the hell out of me."
was to delay
the redesign,
inspections
and
He went on to talk about
handling
the safety
issue
strict
process
control,
thus
At the same time he supported
efforts
which
downstream
the only way
by changing
launching
the
first
resolved
that the approach
he took was more
managed
risks versus
consequences.
managing
risks driven
by political
Engineering
their
have
believe
in general
involves
necessary.
six Shuttle
the issues.
flights
He asked
The
approach
consequences
not only technical
factors
but also
Level II Shuttle Program Manager at Johnson Space Center (JSC),
was a master at listening
to technical
presentations
in detail and
of conservatism
are acceptable.
elaboration
of these
Bob
effectively
"I must effectively
people in terms of
integrity and their conservatism.
If the decision I think is correct is agreed to by the specialists
confidence
in and who are conservative,
the decision is easy. If they don't agree, I consider
to be their level
the
because he said, "Their
accomplishment."
He
His answer, paraphrased
as best Bob Ryan can remember,
what is said; however, I try to gauge the different technical
mind the risks and consequences
The decision can be somewhere
further
but politically
honor
after each flight,
factors.
Bob Ryan asked Bob Thompson,
how he made decisions.
Bob Thompson
asking penetrating
questions.
listen to each and understand
costly
he could
parts
Ryan to write a paper on the dynamic issues and their resolution
as lessons learned,
resolution
was one of the keys to Shuttle's success, and he felt it was a meritorious
understood
together
Main
SSME
would
viability
were working
are made.
Shuttle
(SSME)
political
He said that when he and Bob Ryan
into how decisions
Engine
dynamic
Manager.
and feeling
versus
the level of unconservatism
others
have,
balancing
that I
what I
in my
between the conservative
and unconservative;
then I make a decision.
between the differences
or can be the unconservative
if the risks versus
In the discussion
general
points
of the various
task
examples
in the following
sections,
will be presented.
29
i
i
!
0
,i
i
i
i___
i
i .......
_n
.............
_
i
I
! ...............
!
!
I
i
i
i
.....
ii
i............
i
..............
i
I
I
"m
i
0
,,=
e-
(/)
o
s_
E)
2
_.. _
•
Figure
30
14. Design process overview.
1
._
t ._1
4.
The purpose
DESIGN
of this section
the key decision
gates currently
tion is a symbolic
the design
for launch
visualization
that characterizes
various
design
Included
in this characterization
activities
are achieved
functions,
and
studied
in order
via vertical
technical
process
vehicles.
functions
technical
integration.
system
of multidisciplinary
of a baseline
The
launch
the tasks,
The design
of how
are a complex
a characterization
workflow,
and their
is a representation
and horizontal
integration
to develop
process
design
enabling
interaction
functions,
activities.
vehicle
descrip-
associated
significant
and
discipline
This has been
design
process
which
is
overview
figure
shows
the
in this section.
An
overview
of section
following:
Various
subsystem
tree, stack
diagram,
N×N
levels
process
activities
and
discipline
products
The
conduits)
gram
illustrates
information
"T-model"
the
to show
development
discussion
stage
are
supported
integration
the design
design
design
function.
of parameter
Subsequently,
matrices
gates
and the tasks
complete
the characterization
of the baseline
with the launch vehicle generic information
wide-ranging
conceptual
description
applicability,
design
stage,
is applicable
it has been
applied
and then it is applied
stages,
of the
design
tree with an I×I diagram
functions
simulation,
structure
are responsible
and
testing
activities
of the
by the
technical
integration.
and disciplines.
each of the design
project
framework
and a
functions
integration
is presented
that is overarched
is specifically
of philosophies,
uncertainties;
information
characterization
and horizontal
dia-
to the achieve
technical
process
The NxN
technical
balanced
of project
the design
The
for hard-
(represented
conduits)
with vertical
procedures,
addressed
and
in
criteria;
specific
enabling
disciplines
and associ-
the desired
product
attributes.
In parallel
with each specific
design
function
and, eventually,
associated
design
the
formal
implementation
with associated
integration;
act. For the various
enable
it is appropriately
first. Then
T-model;
the I×I interface
through
functions
where
gate diagrams;
is managed
a discussion
functions
of requirements;
horizontal
of the decision
This process
plane
specialization;
into a subsystem
by analysis,
information
are provided
vehicle
that
The design
by the circular
among
aerospace
balancing
is compartmentalized
to the system
14. This
decision
processes
the tree elements.
for the characterzation,
the flowdown
ated multidisciplinary
are generic
(represented
flow
the launch
with the system
process
that
flows
of technical
which delineates
the design
flow of technical
and informal
(i.e., all of the attributes)
requirements.
To set
and
The system
functions.
in figure
and reintegration;
the supporting
data flow among
software
square
as seen
planes;
reintegration
integration.
interface
given,
function
diagram,
and
technical
representing
4 is now
of compartmentalization
of design
compartmentalization
order
figuratively
process
functions.
ware
is to describe
CHARACTERIZATION
used in the design
discipline
presented
PROCESS
launch vehicle design
flow description.
2
to all the launch
to the design
process.
vehicle
sequence
to the preliminary
The baseline
design
stages.
process
design
to
is merged
To demonstrate
at a top level. First,
and detailed
is presented
a
it is applied
this
to the
stages.
31
4.1
Technical
is needed
integration
to provide
Project
is required
an organized
Technical
Framework
to be accomplished
and disciplined
in an orderly
structure
fashion;
to requirements
therefore,
definition,
a framework
project
workflow,
WBS, configuration
control, systems analyses,
trade studies, system verification,
reporting,
documentation, etc. This framework
is developed,
maintained,
and coordinated
via the functions
of project planning,
control,
and
documentation.
systems
engineering
sense;
i.e., the definition
discipline.
In the application
activities
is generic
design
The primary
activities
the functions
of planning,
section
that the products
4.3.2,
discipline,
integration
(see section
tools
and functions
and requirements,
4.3), which
is orchestrated
interaction
The project
framework
of the systems
engineering
discipline
the other
disciplines
accomplish
the complex
design
functions
to achieve
are implemented
leader
engineering
via technical
The purpose
of this section
is to delineate
framework.
In this sense,
it focuses
project
stages,
project
main
products,
technical
details
related
to the
4.1.1
Project
Stages
Most
projects
projects
effort
STS
into stages
is successful.
(see fig.
Historically
to the conceptual
and various
through
studies;
definition
of preliminary
advanced
developments
risks. These
32
activities
correspond
concepts
trade
are selected
system
manufacturing
requirements
correspond
The
leader
needs
in an
and to balance
their
results
he uses the
he leads
tools
the various
via
integration
While
are
and
of the other
design
planes
integrated
with the STS design
that are considered
typical
process
typical.
organizations,
functions
associated
the project
design
for trade studies.
analysis
15). It has been
the phases
goals are to determine
concepts
then
distribution,
design
feasibility.
assessed,
are achieved
in the process,
associated
highlights
B, C, D, and E. In phase A, the major
These activities
and
to
and
process
They
are
and roles
and
control,
and
of planning,
7, 8, and 9).
are subdivided
that this approach
specifications.
select key aspects
on specific
For more
(see references
from
the design
and structure.
and between
and
be noted
specifications
with technical
design
to the
are in executing
leader. The project
order
tasks
above,
the
discipline
contributes
plan. All these
to achieve
view.
integration.
project
documentation
discipline
among
engineering
STS design
him to orchestrate
balanced
interactively
multidisciplinary
by the project
challenges.
enables
the necessary
in a global
it supports
7, 8, and 9. It should
associated
by the
engineering"
process,
analysis
as delineated
by the project
by providing
engineering
that stress
are validated
tasks
systems
design
and an operations
multidisciplinary
accomplished
is delineated
the systems
see references
design function
fashion
orchestrates
balanced
and documentation,
attributes
manner.
in an orderly
in the same way
engineering
technical
and effective
that view,
of the systems
design
its attributes
From
respectively).
of the system
are
discipline
to the STS
and 4.3.6,
balanced
efficient
design function
control,
the demanding
plane.
functions
to be the "classical
discipline
4.3.2
attributes,
to accomplish
these
engineering
by many
engineering
(see sections
with
6, the systems
on the system
the system
function
associated
and considered
systems
leader
is through
structures
activities
In reference
of classical
of the project
contribution
The
objectives
stage. Additionally,
through
along
requirements;
refined
system
definition
various
projects
are A,
with assessment
of
the need for technology
is
In phase B, the focus is on refining
and simulations;
and test
demonstrated
with most NASA
and support
of advanced
the selected
requirements;
technology
for focused
funding;
and assessment
of technical,
cost,
to the preliminary
design
stage. In phase
C, the focus
is on completion
and
and schedule
of
detaildesignof the selected
facturing,
design
testing,
concept;
operations,
supporting
and qualification
hardware;
checkout
systems
of hardware
of flight systems;
spond to the manufacturing
operations
and disposal.
Throughout
ized with formal
in figure
and facilities
and systems
the duration
reviews.
as planned.
intermediate
laboratories
are as follows:
requirements
• Preliminary
Design
• Critical
Design
• Design
Certification
followed
with
Management
NASA
the requirements
ing programs
Review
and
to the detail
hardware;
verification,
and integration
activities
In phase E, the focus
corre-
is on mission
stage.
the aforementioned
the project
phases
milestones;
is to focus the progress
process
reviews
These
of flight
of the program
i.e., project
of the project
are final-
gates,
and are shown
and verify
that the project
there are about 12 major reviews; however, there
that must receive major support from the design
(SRR)
(PDR)
(CDR)
Review
(DCR).
that occurred
specified
Instructions
Recently,
review
Review
reviews
clearly
represent
reviews
Throughout
the design
reviews. The project
• Systems
stages.
to the operational
process
manufacturing
of final manu-
correspond
and initial flight operations.
integration]verification
reviews
of these
and development
plans. These activities
for flight;
operations;
of the design
These
16. The purpose
For all formal
launch
analysis;
and test of prototype/protoflight
and software
This corresponds
is proceeding
are numerous
replaced
of detail systems
stage. In phase D, the focus is on development
validation,
defines
performance
outputs.
in the past, there
was a specific
The
for these
guidelines
process
reviews
that was required
were
contained
to be
in NASA
(NMI's).
issued
updated
procedures
that managers
must meet
projects.
The
program
phases
and guidelines
in formulating,
discussed
with four
subprocesses.
They
are as follows:
and (4) evaluation.
The various
design
stages
Conceptual
Design
Manufacturing
Process
IIII_ I
above
in figure
(2) approval,
15 must
It
and evaluatE) have
been
(3) implementation,
still be accomplished
by the
Detail
Design
I_
Integration
and
System
Verification
m
of systems.l°
implementing,
(i.e., A, B, C, D, and
(1) Formulation,
delineated
Design
Preliminary
for the management
approving,
Operations
_
,.,i
'_ Design Process
Figure
15. Major
project
stages.
33
leader
whether
must
be
appropriately
they are called
management
guideline
is "faster,
(2) end-to-end
customer
management,
(5) missions
Standards
phases
tailored
Organization
or subprocesses.
for
better,
involvement,
enabled
However,
efficiency
and
and cheaper."
The themes
(3) comprehensive
by technology,
the manner
effectiveness.
that they are accomplished
The
are as follows:
definition
(6) technology
rationale
behind
(1) Tailoring
and requirements
the
the process,
control,
(4) risk
commercialization,
and (7) International
_D
OE
(ISO) 9000.
• Classical
I-Pre-OA-.),I_--OA_',_
I Mission I
Mission
I
@B
_;
_C
_
System I Preliminaryl
Final
I Fabrir4,ti°n I
_-',_
Prepfor I Dep_mentl
Mission
I
Disposal
FeasibilitM_
DefinitionJD
Definition
_r,
Design _ Design _lnte_tion_Deployment_verifUicabtion_Operations_
R
R Snn SDR
PDR
CDR DCR SAR
FRR
ORR
DR
J\
I
Fabrication, Integration
and Ground Verification
I
I
• Typical
I
In-house and Contractor
sys,Dff andI_ BStudies I Contractor
I
System I PreliminarYl
Final
Definition,
Design I
O_sign _¢
_C Contract
PDR
I
Award
CDR - Critical Design Review
ORR - Operational Readiness Review
OCR - Design Certification Review
DR - Disposal Review
FRR - Flight Readiness Review
POR - Preliminary Oesign Review
PRR - Preliminary Requirements Review
SAR - System Acceptance Review
MCR - Mission Concept Review
MDR - Mission Definition Review
SDR - System Definition Review
SRR - System Requirements Review
Figure
4.1.2
Main
Project
stage there
is given in various
that each project
NASA
can tailor
are certain
products
documents.
These
the products
are subject
to peer review,
and certain
of the leader
to determine
what products
on schedule,
and cost effective.
The products
delineated
some
indication
to as review
added
Typical
of what is needed.
item discrepancies,
the project
to become
when
the products
are completely
34
discipline
supports
with the specific
design
associated
where
sound,
all these activities
results
However,
are expected.
with the various
the projects
It is the responsibility
is technically
sound,
stages
are shown
in figure
however,
they provide
review
on schedule,
formal
by organizing
and action
stages.
of these
in the sense
and are not all inclusive;
programs,
through
specification
to be guidelines
that their project
the peer review
a delta
in very complex
integrated
and others
to demonstrate
to be illustrative
In cases
A generic
are meant
are required
products
technically
tracking/documenting
that are required.
specifications
are needed
there is usually
forces
subsequently
consistent
products
here are meant
at that time. This can happen
engineering
phases.
Products
For each design
products
16. Project
items.
results
in excessive
criticisms,
for that stage and additional
and the value added
and cost effective.
and informal
products
referred
can be
is that the peer review
Reviews
communications.
and coordinating
17.
the various
are successful
The
systems
reviews
and
Communication
andInlegraUon
Detail
Design
I I Manufacturing
• Final Design and
• Hardware and Software
Specifications
Ready for Assembly
Test Verification
J Preliminary
I I
Design
• Feasible Project
• Preliminary Design
Concepts
Concept(s)
• Trade/Sensitivity
Results
* Subsystem
and Requirements
Components,
• Selection Criteria
• Refined Top-Level
Elements,
• Refined Requirements
Definition
-
Requirements
. Trade/Sensitivity
• FacilitylGSE Concepts
• Interface DefinitionllCD
• Risk Assessment
• TRL Assessment
- Technology
Needs
Results
and Software
, Demonstration
• Facility and GSE Hardware and Software
• System Design and OPS
Validafion and
Requirements Are
Satisfied
Certification
• Product Improvement
Procedures and
and
Constraints
Assembly Process Requirements
- Built-to-Specification
, TRL Assessment
• Detailed Verification
, Pertinent Tests
• TRL's Must Be Satisfied
• Top-Level Verification
Plan
• Quality and Acceptance
Rec!uirements
• Preliminary
* Facility and GSE
Facility and
Procedures
That
• Operations (OPS)
• Manufacturing
GSE Requirements/Concepts
• Pertinent Project
• Finalized OPS
• Flight Ready Hardware
and
and System
• Risk Assessment
• Pertinent Project
Documentation
Parts,
"n'I I Operations
Refined
and Verified
Plan
Requirements
• Preliminary Operational
Documentation
Procedures and Constraints
• Pertinent Project
Documentation
I Products
Successfully
Delivered
Figure
4.1.3
should
Technical
Effort
Rate
A typical
technical
Through
Communicalion
17. Project
main
and Integration
products.
Distribution
effort
be clear that each specific
rate distribution
project
is illustrated
will have
in figure
its own particular
18 for the various project
distribution.
6 percent of the technical
effort is allotted to the conceptual
design stage
the preliminary
design stage. The remainder
of the effort goes into detailed
integration,
should
and verification.
be allotted
more
effort
into the conceptual
tionary.
At least 80 percent
design
stage
4.1.4
Typical
(see section
design
design
stage,
of the life-cycle
is some
stage.
ture. The elements
several
from
reference
the amount
in the engineering
in situations
are determined
It can be seen that about
and about 20 percent
design, manufacturing,
regarding
is a trend
especially
costs
where
by decisions
of effort
community
the design
made
allotted to
systems
concept
that
to put
is revolu-
during
the conceptual
is shown
the leader
4.4.1.1).
projects
can be organized
as shown
subsystem
teams. While this structure
that the design process as characterized
past,
controversy
There
It
Organizations
Engineering
supporting
it is noted
At this time there
to the conceptual
stages.
of the design
different
types
11, but
process
modified,
19. In this figure
and
can be considered
typical of a project type organization,
herein does not depend upon any organizational
struc-
must be executed
of structures
slightly
in figure
have been
shows
regardless
implemented
four
basic
of the organizational
to achieve
types
the project
of organizations
structure.
In the
goals.
Figure
that
have
20
been
35
1.4
m
t.2
Manufacturing
--=
O
1==
ULJ
1.0
--
0.8
•I=
0.6
DetailDesign
"_
SystemIntegration
andVerification
PreliminaryDesign
0.4
Conceptual
Design
0.2
I
0.2
I
0.4
I
0.6
I
0.8
I
1.0
ScaledProjectDuralion
Figure
18. Project
total technical
effort
rate distribution.
Leader
and
Deputy
Safetyand
Mission
Assurance
I
I
Lead System
Engineer
Lead
Subsystem
EngineerA
Figure
36
19. Typical
t
Staff
Functions
]
I
(Project Control) I
Lead
Subsystem
EngineerB
project
management
I
I
Lead
Subsystem
EngineerX
Lead
Subsystem
Test Engineer
organization.
implemented
product
in the past.
teams
discussed
(IPT)
have
Figure
21 is intended
been
used
Engineering
organizational
manner. As mentioned
shown
in figure
past.
types
These
of organizations
organizational
where
integrated
structures
are briefly
attention
operation
matrix
managers
can achieve
specific
organization
usually
ers. If the engineering
the project;
task is complex,
formally
and on a regular
All other
engineers
work informally
This type
level engineers
is frequently
the necessary
is required.
In this case,
in addition,
with the functional
representatives
the leader
interacts
matrix
technically
in the aerospace
are directly
responsible
to the leader.
Their
to use the project
organizational
structures
delineated
organization
here are basic,
as opposed
and many
to functional
and automotive
the lead engineers
relationship
to the functional
is not technically
There has been
responsible
for
a recent trend in
to the matrix
variations
managmanagers.
In this structure
industry
of the funcThe leader
organization.
the automobile
some
then a
is favored.
is the project
manager
as needed.
require
is not too large,
structure
functional
discipline
but the functional
interacts
with the functional
managers
in addi-
may
and the functional
and report
popular
function
product
from
cost
are
development
with the functional
organization
lead engineers
very
design
a certain
if the project
lead engineer
has been
system
hand,
Again,
with the functional
structure
used when the product
On the other
then a heavy-weighted
basis
of organizational
The final organizational
manager
is to maintain
their work. The leader
leader
can be suitable.
support
interacts
and the working
structure
of the organization.
such that a project
tional organizations
managers.
organized
and the functional
tion to the functional
light-weighted
types have been structured
to achieve project goals in the most
above, four of the most commonly
used organizational
structures
20. The functionally
is not too complex
industry.
recent
below.
effective
special
to show various
in the near
organization.
of these have
The
four
been implemented.
Functional Manager (FM)
PMra°_eaC_e
r
Ass st_
Grou of professionals who execute
the_ tctivities in product creation
Liason
" Area of Strong Project
Representative (L) Manager influence
Leader
Light-Weighted
Functionally Organized Structure
Matrix Organization
Dev.1
Dev.2
I
Dev.3
i
I
i
,®
i
i
Leader
-Leader
Heavy-Weighted
____i
Project Organization
Matrix Organization
Figure
20. Typical
organizations.
37
Engineeringorganizationalstructureshavebeenfine-tunedrecentlywith the implementationof
IPT's.TheIFF's area variationof a projectteam.Shownin figure21 arethreevariationsof IPT's.The first
teamstructureis of atype wheretheIPT is technicallyconnectedtothefunctionalorganization.Theteams
canbecolocatedor the memberscanremainin the functionalorganization.The functionalmanagersare
responsiblefor the technicalengineeringwork, andthe informal integrationis within andbetweenteams.
The leaderis responsiblefor activitiesassociated
with the systemdesignfunction.This structurehasbeen
popularandvery successful.In thesecondtype,theIPT is connectedto thefunctionalorganizationthrough
proceduresandstandards.Theteamsarelocatedwithin the project,andthe informal integrationis within
andamongteams.Again,theleaderis responsiblefor activitiesassociated
with thesystemdesignfunction.
The functionalmanagermaintainstechnicaldisciplinebut is not technicallyresponsiblefor the engineering work. The third type of organizationalstructureis where the IFF is completelyindependentof the
functionalorganization.Theteamsarelocatedwith the projectandtheinformal integrationis within and
amongteams.Theleaderis responsiblefor activitiesassociatedwith the systemdesignfunction.Thereis
no connectionbetweenthe working engineersandthe functional managers.This particularstructurehas
provento be unsuccessfulin somecases.
It hasbeenlearnedthatwhenengineeringspecialistsareseparated
from thefunctionalorganization
for morethanabouttwo years,thereis anerosionof their technicalexpertise.Someorganizationsmovethe
technicalspecialistbackto thefunctionalorganizationafterabouttwo years.
4.1.5 Roles
The system
design
the mission
statement
allocated
to the other
compatibility
the cost,
function
of the system.
There
requirements
must be integrated
All other factors
design
function
must
be technical
is responsible
management,
Again,
the tools of the systems
ments
and provides
TRL.
The
documentation
leader,
who
the process.
38
are
and
engineering
of systems
design
balance
to ensure
are then
balance
effort
discipline
are applied
function
discipline
to aid planning,
process
plays
elements.
management
and
to meet
is to provide
cost,
an important
as well
there
must
configuration
to support
safety,
design
process
The
design
function
system
discipline
in planning,
as requirements
be
verification
management,
etc.
activities.
that meets
all the require-
operability,
schedule,
role in this process
to achieve
engineering
these
the best system
reliability,
and certification
parties
addition,
and management,
of performance,
by the systems
In
risk analysis
engineering
of all critical
technical
with all contributing
flowdown.
implemented
is supported
to transform
These
into the total engineering
for the overall
interchanges
and audit, interface
a proper
must be integrated
configuration.
objectives.
planning
systems
like QFD
All system
functions.
analysis,
tools
tools
design
management,
specific
discipline
and a system
definition,
The challenge
engineering
requirements
and technical
The systems
systems
of system
of all interfaces.
schedule,
uses
into a description
where
control,
and
the disciplineto provide
is the responsibility
controlling,
and
the
of the
and documenting
)FM
XXXX
Leader
I_T-1
L vel-2
)L
IPT TechnicallyConnectedIo FunctionalOrganization
DFr_
e f _1 _IFM
i Fr_
I Dev.2
Dev.3
Manufact
Procedures and Standards
IPT Connectedto FunctionalOrganizationThroughProceduresandStandards
f PT-1
Leader
_, eveI-E
IPT CompletelyIndependentof FunctionalOrganization
Figure
21. Integrated
product
teams.
39
4.2 Technical
Technical
integration
is the fundamental
fiber
with
intensity
process.
It is accomplished
various
stages.
Technical
integration
addition,
there
are various
other
describing
attributes
with a description
4.2.1
Technical
(Peenemtinde
Team)
that goes
will be illustrated
integration.
through
every
as the design
process
using
that are known
of the enabling
Integration
The T-model
an increasing
factors
of technical
along
Integration
In this section
factors
a symbolic
to enable
and a typical
factors
is provided
activities
in-depth
discipline
chosen
discussed
the T-model
(or component)
two specific
levels
(i.e., above
the dashed
integration,
formal
tors and operatives
rily upon
to illustrate
technical
for technical
certification
integration,
integration
integration
aspects
All system
shown
resolved
at this level.
while
to the space
for technical
integration,
or top-level
integration.
The leader
The concerns
purpose
decisions
In addition,
The emphasis
process;
is on overall
to a balanced
related
planning,
control,
names
are the primary
integration
balance
conflicts
and
are respectively
related
• Systems
• Formal
• Top Level
---t
• Specific Discipline to
Specific Discipline
o,sc,0,,no
1 ,
, Ij:o'sc'0"no
:com0ooeo,-O,,,I____lt
co oonoo'Integration is Everybody'sResponsibility
Figure
22. Technical
integration--T-model.
level
facilitais primaand
of performance,
via managing
and documentation
in
of system
management
is achieved through
interfaces
associated
product
technical
results
22. The upper
technical
with a proper
interactions;
process,
in figure
and his office
the product
is to converge
represents
by the interchangeable
and TRL. Technical
integration
parties, customers,
and similar
and all system
era. Contempo-
design
of this level of technical
i.e., the focus
are delivering
all system
the crossbar
as parts of the T's crossbar
is known
Horn
environment.
This model has
The stem of the T represents
T-model forTechnical Integration
40
In
of as
Helmut
Saturn/Apollo
transportation
integration
operability,
schedule
with all contributing
related
i.e., a model.
can be thought
in this document.
during
of technical
of the design
The continual
conflict.
and penetration
applied
of this level of integration.
of the system.
process.
when
integration
crossbar)
cost, reliability,
safety,
nication and interaction
design
activities
The model,
of technical
the system
the
Model
has been
integration.
through
distribution.
rary literature
discusses the attributes
and advantages
of this model in today's
been called the T-model because
it has vertical and horizontal
components.
i.e., technical
of the STS design
progresses
representation;
it. These
a model
aspect
commuwith the
resolving
made
and
to the design
processis maintainedat this level.The level of intensity of the activities
pro_esses
through
the various
lower
level
The
names
of specific
discipline
discipline-to-discipline
(i.e., below
to specific
of technical
are the primary
operatives
the engineering
design
can also denote
in-depth
discipline
capability
compatibility,
specific
If proper
cannot
organizations
to document
Technical
(2) the
(caveat--not
having
aware,
of the process
that
interactions,
of all the discipline
to achieve
a balance
of
to the upper
level for
of the discipline
results.
Factors
effective
technical
integration
include
(4) proper
in turn
correct
integration;
that
(1) an electronic
interactivity;
and
inherently
connect
communications
certain
(3) interactive
overview
(5) interactive
disciplines
team
by leader,
feedback
members
functional
of requirements,
and architecture.
if proper
must be very
to provide
and understanding
among
by being
verify
data
items.
Throughout,
check
4.2.3
Technical
Integration
Throughout
determine
aware
the various
is occurring?
if uncertainty
design
functions
Activities
Distribution
stages
of the design
technical
the process,
Use a state-of-the-art
Check
and have
to determine
is converging,
Throughout
inputs
and disciplines.
integration
check
compatibility,
the scaled
issues.
to the participants.
of informal
At each iteration,
for consistency,
23 delineates
integration
alert to the integration
information
interactions
trends,
technical
pertinent
and accomplishments.
Figure
aspects
It is the responsibility
fosters
and participants
changes.
have
must bring the conflict
resolution.
that
cognizance
of the
must
process.
the specialists);
ensure
legs
an iterative
among
tailored
vertical
engineers
through
programs
system
of integra-
The
with other disciplines
function
system
their technical
to ensure
of the design
adequacy
This is accomplished
of sizing
How does one know
activities
integrate
interactions
etc.,
functional
aspects
of configuration,
is on the technical
for personal
leadership
The
must be knowledgeable,
maturity
connectivity
advisors,
continuous
engineers
internal
strategy/philosophy,
ment
process.
represents
facilitators
that individual
a substitute
strong
managers,
that enable
focus
functions.
other
Enabling
design
It signifies
of input data,
then the design
and report
Integration
factors
design
or some
process.
are the primary
as well as the systems
etc. The
be achieved,
of the
integration
the crossbar
of the design
4.3.1)
interchangeable
or in-depth
below
disciplines,
and how they horizontally
of requirements
process
stages.
are the pedigree
for the specific
portion
These
attributes
balance
system;
design
by the
integration,
perspective.
uncertainty,
attributes
The
aspects
engineers.
interacting
considerations
reallocation
4.2.2
specific
of discipline
the various
is given
for discipline-to-discipline
(see section
sensitivity,
design
informal
in the horizontal
of integration
with a systems
to their respective
throughout
The design
the allotted
activities
crossbar)
interactions
functions
tion for the component-to-component
T-model
they impact
discipline,
or component-to-component
process,
and responsive
the dashed
integration
organizations
while
as the design
stages.
of integration
(see fig. 22). The emphasis
increases
communications
and outputs
Determine
participants
independent
required
to
the extent
of
display
if the right problems
and have
manage-
experts
integration
are being worked,
evaluate
critical
and convergence.
process
effort
the distribution
rate
variation
of the technical
with
scaled
project
effort
rate
duration.
41
The
major
total
technical
(2) technical
integration.
other technical
efforts
informal
integration.
effort
Technical
required
the project
where
the major
integration
starts
formal
integration
ware
product.
representative
balancing
of design
groups:
In each specific
engineering
this difference
activity
and discipline
achieved
levels
during
in figure
project,
peaks
engineering
to ensure
_lu
0.6 m
••
•
TechnicalActivity
l
iI
iI
0.4
.,r a
0.2
.....................................................
.............
.......
-
-
"!
0.2
.,- ._
"
,_"""-Technical Integration
"Formal Technical Integration
I
I
I
I
0.4
06
0.8
1.0
Scaled Project Duration
Figure
42
23. Technical
integration--activities
distribution
distribution.
of a
however,
is an appropriate
._ •
,"
The
may be different;
08
u
The
hard-
o
jl
occurs.
the project.
formal
1.0
o o
through
The
a typical
that there
and
as a validated
Total Effort
c
and
of formal
effort
1.2
//p J
engineering
midway
1.4
t_
re"
and
of the project.
together
23 represents
the distributions
should be studied
about
out throughout
comes
activities
is composed
this part
since the project
shown
and discipline
integration
up, and then
acts are being
(1) Technical
function
Technical
function
ramps
the rate distribution
difference,
all design
the project.
at the end of a project,
In summary,
project.
include
into two
23, it can be seen that the technical
expenditure
to increase
there is a significant
of all the activities.
activities
off at a low level,
and informal
tends
can be categorized
to complete
From figure
technical
major
rate
if
focus
4.3
A symbolic
consists
tions,
representation
of three categories
and discipline
and enhances
design
the capability
vehicle
technical
functions
function,
process
is developed
the T-model
functions.
in this section.
subsystems,
of technical
All this enables
the symbolic
integration.
The features
of hardware/software
In addition,
the IxI and NxN
by a description
of the launch
between
functions,
connections
design
design
integration
are delineated.
This is followed
each design
design
They are hardware/software
and discipline
to achieve
and discipline
act are illustrated.
tion illustrates
Model
After compartmentalization,
and to the design
functions,
balancing
of the launch
of compartmentalization.
functions.
to the subsystems
Characterization
vehicle
It
func-
is applied
representation
subsystems,
matrices
system.
and the
This descrip-
how they are enabled
by vari-
ous discipline
functions,
and the launch vehicle
system IxI and NxN matrices.
In addition,
this section
includes what tasks must be achieved,
what product attributes are developed,
and what decision gates must
be passed.
All of the aforementioned
NxN matrix,
WBS's,
is discussed
and tasks in reference
in a parallel
2 are included
fashion
to show
for each design
the relationship
function.
Also,
to the process
the
symbolic
representation.
4.3.1
Features
The
success
an effective
principal
of Description
of the design
and efficient
engineers
The
manner.
process
depends
Initially,
the principal
from the functional
first category
vehicle
system,
divided
into subsystems
upon
organizations
of compartmentalization
payload
interfaces,
and
technical
from the systems
accomplish
compartmentalization
consists
operations
and so on, as illustrated
are supporting
design functions
and discipline
tions will be illustrated
below. The information
achieving
engineers
of dividing
system.
in figure
Then
24. Each
integration
and achieving
design
and the
(see section
2.0).
the STS program
the launch
division
vehicle
results
it in
function
into the launch
system
is further
in a "system,"
and there
functions
for each system. The design and discipline
funcflow associated
with these systems consists of allocations
from the parent system and suballocations
to the lower-level
subordinate
systems (subsystems).
Then there
is also information
flow associated
with interface requirements.
It can flow from the parent system, from its
peer (i.e., mating
interfaces,
subsystems)
and from its lower-level
types of information
flow between these systems,
functional,
and informational.
It is of paramount
tions. These
can be determined
interactions
in this category
The
second
through
experience,
analysis,
trated
(the third category).
in the following
of compartmentalization
subsystem
2.2.3.2
design
2.2.3.2.0.1
the figure,
From
First,
in fig. 25). Recall,
fuel tank system
other design
The distinction
example.
functions
but with cognizance
function.
consider
in figure
it can be seen that the entire
stack.
functions
aspects
The information
of technical
pertain
design
the design
the fuel tank system
in the corresponding
In addition
to those
to mechanics
flow and
integration.
of how the design
To further illustrate
the design process,
a distinction
design functions
(the second category)
and discipline
between
It is shown
of the other design
test, or simulation.
are important
specifications
of the system are actually
achieved.
must be made between the sometime
misunderstood
functions
systems.
there are also interactions.
The interactions
are physical,
importance
to track and account for all interface
interac-
of compartmentalization
and third categories
subordinate
functions
and discipline
functions
of the fuel tank subsystem
design
specifications
fuel tank system
The design
in the stack.
functions
design
design
This aspect
(see the fuel tank
are the responsibility
25 at the top of the "stack"
is illusof the
and is designated
activity
is supported
as
by
from their own perspective
of technical
integration
that is
43
STS
1.0
I
I
I
2.0
Launch
Vehicle
,
,
I
Propulsion
Systems
Vehicle
Structures
Thermal
Systems
I
I
Thrust
Structure
I
I
Aeroshell
Tankage
I
I
I
2.2.3.2
Fuel
Tank
Oxygen
Tank
associated
24. Launch
with the stack will be discussed
provides
hardware/software
design
function.
In turn
system
design
specifications.
tank
vehicle
subsystem
specifications
system
design
the
Intertank
2.2.4
I
Structure
Payload Bay
Structure
I
!
I
2.2.3.2.3
Propellant
Utilization
System
I
Propellant
Conditioning
System
compartmentalization.
section.
Ideally,
each design
the allocated
is responsible
is a typical
Operations
4.0
Systems
shown as an example)
(that satisfies
function
The following
I
subsystems
in a following
design
I
subsystems
hardware
i
Systems
I
Figure
I
I
2.5
Other
I
2.2.3.2.2
Tank
Thermal
System
(Selected compartmentalization
I
Payload
3.0
Interfaces
I
2.4
Avionics
Systems
I
I
2.23.2.1
Tank
Structure
I
requirements)
for developing
list of the design
function
in the stack
to the system
integrated
functions
fuel
that support
tank
the fuel
design:
•
•
Fuel tank systems
GN&C (for slosh baffle
•
Structures
•
Thermal
•
Avionics
•
Materials
requirements)
• Manufacturing
•
Other
The
systems.
hardware/software
persons
called
software
configuration
candidate
subsystem
desired.
designers.
Designers'
The designer
along
products
has the ultimate
responsibility
attributes.
that are then
functions
analyzed
Designers
are designed
for specifying
conceive
to see if they
by a person
will successfully
synthesize)
perform
and software
specifications
that define
their subsystem.
(drawings,
manufacturing
instructions,
etc.) would
tank thermal
also include
systems,
propellant
the associated
utilization
design
system,
attributes
and propellant
such as performance,
or
the final hardware/
(hypothesize,
are drawings
all tank structure,
44
by design
the specifications
example,
it would
delivered
with the associated
configurations
fuel tank system
In addition,
specifications
conditioning
as
For the
be those
of
system.
cost, reliability,
etc.
.........
+i ++
i
m+
LL-
,-=_
,,il
:/
F_
G,
C
l,/.,.
-'°'"
! I_'_
i
_
1¢
's
=i
I
_IP.-,
,
B
_cm--
E
'... "+.. -,
E
,i,
.-. +
, ,++_
,''_"
1
II
,
I .....
.....
iI_
,to
+, _
i
....
-
"t ;,__m,
,_
::--+--,
m
I
.,:1_
,
y_'_
_a_
7 ....._, '
.-.,_
.....
_,
,
_m. ,,N_._:
,,.,LI
L#--Figure 25. Fuel tank example:
Subsystems,
design functions,
and discipline
functions.
45
In summary,
what
the designer
does
is called
function.
As can be seen, there
are design
function
software
subsystem.
principle
applies
sub-subsystems,
The
same
components,
On the other hand,
of specialty
concept.
reside
on the design
in a following
• Structural
as the subsystems
functions
(third category
Discipline
functions
perform
function
support
"plane."
A typical
Structural
Stress
-
Durability
Vibroacoustics
the design
functions
This particular
list of disciplines
aspect
for an engineer
to have both a design
but in some other
areas
synthesize)
a control
and perform
at different
locations
In summary,
design
functions
are the interacting
cations.
There
is a "stack"
"system"
plane
of the stack
for providing
functions
reside
is responsible
on the plane
in multiple
In the previous
discussion,
The designer
integration
and they
will also be discussed
the discipline
of system
ning, control,
and documentation.
After
the first and second
with a listing
these products.
of hardware
The design
function
engine
structures
was addressed
the focus
the discipline
and software
design
promote
would
is
Dis-
a stress
If
ana-
find his respective
the three
vehicle
design
related
the necessary
for producing
to design
activities
the
plane
process
with the required
intega'ation
of
(see 2.0
for the total
on the system
are completed,
along
categories
system
function
responsibility
Also resident
functions
products
and
or testing.
(For example,
to illustrate
who has the ultimate
of compartmentalization
functions
or subsystem.
plane.)
the system
specifications.
specifi-
etc. The top
in the stack
will be on the launch
plane represents
of those
subsystem,
system
structure
be
specifications.
that they are analyzing
engine
can
functions
on more than one plane.
and the main
that performs
design
for its respective
and the main
discussion
categories
the other
design
the development
with each system,
specifications
to hardware/software
engineering
the design
to support
role. This
engineer
that produce
for integrating
the fuel tank system
in addition
may both conceive
That
as planes
needed
system
the same engineer
on that system.
in at the time.
associated
they reside
plane
function
engaged
planes
in this case is the leader
drawings
46
attributes,
the activity
functions
structure
the top-level
total vehicle
tasks to produce
tank
In the following
In this situation,
begin
the desired
role and a discipline
analysis
upon
of the specific
subsystems,
on the fuel tank structures
compartmentalization.
function
the hardware/software
on both the fuel
tem plane
design
the following:
such as control,
depending
discipline
lyst doing
system.
to achieve
function
can be represented
of design
they are involved
work
system
on the plane
On each plane
vehicle
areas
of a given
analysis
in structures,
on fig. 24).
into
are technical
tests, and simulations
of technical
includes
(hypothesize,
activities
compartmentalized
of compartmentalization)
analyses,
is uncommon
cipline
are further
dynamics
system
It is possible
responsible
design
one to one to each hardware/
analysis
-
• Control
• Etc.
found
for his or her respective
etc.
functions
section.
function
corresponding
discipline
and expertise.
The discipline
the design
"stacks"
is
plan-
on the sysassociated
and communication
to effectively andefficiently executethe tasksto producedesign specificationsthat meetthe allocated
requirements.Toenablethedeterminationof designfunctions,considerationis givenbothto arrangements
thattendto decouplethevariousdesignfunctionsandto arrangements
wherethereis a logicalgroupingof
multidisciplinary activitiesfor eachdesignfunction.Figure 26 representstypical arrangementof design
functionsfor the launchvehicle.The launch vehicledesign processconsistsof the following design
functions:system,aerodynamics,trajectories/G&N,controls, structures,thermal, propulsion,avionics,
materials,manufacturing,andothers.It canbeseenthatall of the designfunctionsareoverarchedby the
systemsdesignfunction.Eachof thedesignfunctionsis enabledby disciplinefunctionsthathaveactivities
that supportthe developmentof the designspecifications.The discipline function activities include
analysis,simulation,groundandflight testverifications,etc.,to accomplishthedesigntasks.
The attributes and specificationsof eachof thesedesign functions are attainedthrough the
multidisciplinaryactivitiesof all the disciplinefunctionssupportingthatdesignfunction.Theseattributes
andspecificationsmustsatisfythesystemrequirementsandnot conflict with anyattributes,requirements,
or constraintsof theotherdesignfunctions.Theproducts,obtainedvia thedesignfunctions,arethelaunch
vehicledesigndrawingsandspecifications,otherassociatedcriteriaandrequirements,andconstraintsthat
relateto the launchvehiclehardwareandsoftware.
All designfunctionanddisciplinefunctionactivitiesmustbetechnicallyintegrated.This is accomplishedby bothformalandinformaltechnicalinte_ation,represented
in figure26.Therectangularconduits
representtheverticalformaltechnicalintegration.Thecircularconduitrepresents
theverticalinformaltechnicalintegration.In addition,thereis alsoin-planeinformaltechnicalintegration.In-planeinformaltechnical
integrationis definedto meanmultidisciplinarytechnicalintegrationactivitieson a designplane.
The formal vertical integrationrepresentsthe flow of informationdownwardsandupwards.The
downwardflow of informationis from the systemsdesignfunction to the other design functions. This
information
mainly
and criteria
and is represented
all the design
functions
(characteristics
design
within
consists
of subsystem
specific
by the downward
to the systems
of the design
design
to be compared
functions
and is represented
the systems design function.
attributes
and insuring
compatibility
functions,
and overall
system
informal
integration
requirements,
pointing
function.
architecture,
arrows.
The upward
This information
to the allocated
requirements,
engineering
managing
management,
and
consists
etc.)
is from
of the attributes
of the design
in-plane
balance
and resolving
certification,
procedures,
flow of information
mainly
by the upward pointing
arrows. Formal
This integration
pertains
to achieving
to the requirements,
philosophies,
from
the
integration
occurs
among the system
conflict
between
documentation
design
of the entire
system.
The
circular
conduit)
flow is between
represents
design
that this information
because
functions
nature
i.e., the attributes
of one design
design
Thus,
compatible)
This flow
and is represented
does not go to the systems
of the iterative
functions.
is both vertical
a flow of information
of the design
function
the final attributes
and in-plane.
informal
integration
and downwards.
The
by the arrow pointing
upwards
design
type of information
process
may affect
from
The vertical
that is both upwards
function.
This
(i.e., the
information
and downwards.
flow
and the fact that the design
functions
the attributes,
or constraints
all the design
and satisfy all the allocated
requirements.
Finally,
of information
results
from the multidisciplinary
requirements,
functions
must be balanced
there is also informal
activities
that occur
Notice
results
are coupled;
of other
(i.e., mutually
in-plane integration.
within each design
47
System
Aerodynamics
Trajectory/G&N
Control
Structures
Thermal
Propulsion
Avionics
Materials
Manufacturing
Other
Figure
function.
Again,
the system
other
level
design
26. Technical
these
activities
requirements
integration
are iterative,
of system,
design,
and discipline
and they are considered
and do not conflict
balanced
with the attributes,
functions.
when
the attributes
satisfy
requirements,
or constraints
of the
the utilization
of the I×I and N×N
functions.
All information
matrices
(see
matrices
are associated
flow
fig. 27). The
is accounted
for and controlled
I×I matrices
with the design
are associated
and discipline
through
with
hardware/software
functions.
As shown
interfaces
and the N×N
on the figure,
the I×I matrices
pertains to input and output data flow associated
with the physical,
functional,
and informational
hardware
/software
subsystems
interfaces.
This type of information
is usually contained
in interface
control documents
(ICD).
Similarly,
interacting
design
provides
a residence
48
the N×N matrices
and discipline
function
and a placeholder
pertain
to input and output
activities.
for information
This
aspect
associated
technical
data
of the design
with the design
flow associated
process
process.
with
characterization
{0p
0
.m
X
,-r_=
Z
X
Z
0
CZ
IJ.
=i
w
.....
T
'
i.... i
I
I
I
,_
,
'I
QP
....
,
:"
iCNJ
'II
I ....
,_
,
_-,
-s
I
_,
-
I
,
'-1
,_
' ¢_dl_
.,..
I ¢.,_,
i_--.,!
I .....
I i_
i_11
I ....
,
.-'-.,
, . _,._
--
.-
'1-
;E'
._opa
!
Q=
I
'
'
,
,_
,- ....
I_N,I
__-_m.=,
I
_
,_._',
'_._
,_.....
,I
:
-_=_
"_
,
,
"I
-¢E_,
, ,_.,"_,,
_r"
,:_., ,_-:_--,
,_
..,'_' ,_
', ,
I"
i
i_l
', '
"-'
,_,
,,,_
,-_-_
'N=
,_
, ....
',"__
I.'=..
_0p
,_=
___,
,I '_I
-_
'._,_=,_ _iii
, .....
°
'_°'
_ ....
,
° _,
,,_,
, .®=
.....
l
E
_.,
_,
!_[_]
. .....
C_
i
I
H
I
oil
_=_
,_=-_
a .
,
,
!
,_
_
,
'1
_ _,
,_._._'
.',
i
Figure
27. Matrices
of input/output
data flow.
49
Technical
integration
balance the program
where the attributes
(Individual
For
act. At the top level the design
and the operational
plan must
requirements
(see fig. 28). During the design process there are numerous
trade studies
between
various
design function
planes are balanced
to achieve
the best design.
engineering
narrative.
is a balancing
design
example,
functions
will be interchangeably
denoted
design
be denoted
the aerodynamic
function
may
balancing
to achieve
as the
trade
studies
are usually
How well the balancing
is achieved
of energy
is capable
of producing
matter ....
Now whenever
a change
is made
Things
are always
place
in a group
of things.
that
only
within
limits,
He states
further,
"The
are in some degree
shall
be...'6
balancing
act. The
determines
is to regulate
28 also
various
the
more
together.
They
do not exist separately
amounts
"Any of these
exactly,
forms
redistribution
of
is left, this event
takes
.... All you can do, and
changes.
and cannot
be reconciled.
All design
for devices
or his client
has to choose
to what degree
and where
the failures
functions
and technical
core
capability
of the
organization,
design
solutions
achieved.
These
solutions
design.
detailed
functions.
of the various
the
to successful
design
the
conflict
discipline
requirements.
Pye states,
and a result
studies
of the original
changes
multiple
of energy
using
compromises
of the product.
that satisfy
at a sufficiently
involve
in things;
the function
Through
be performed
usually
by the passage
shows
integration.
studies
the success
for design
The designer
and must
Trade
changes,
requirements
failures...
Figure
numerous
in the alternatives.
attributes
plane.)
Trade studies that drive out the differences
in design alternatives
constitute
a significant
part
process as managed
by the leader on the system plane. Because of the strongly coupled nature
the differences
optimal
aerodynamic
requirements.
of the design
vehicles,
multidisciplinary
parts of this
plane
level to reveal
is also
in some
In a specific
of launch
there
as planes
of system
provide
analysis
sensitivity
the use of assumptions,
these
design
and
data
This
you
do by design."
integration
in performing
the
that
are used
to perform
trade
simulation
and testing,
analyses,
tradeoffs
can
be made
in general
will be suboptimum
and can
Understanding
and accounting
for the balancing
I
and
consist
I I
of several
act are keys
I oes,on
I I oP P'an
I
Requirements
Project
I
CoreCapability
]
DesignProcessIsa Balancing
Act
Figure
5O
28. Design
process
balancing
act.
and
aternative
Technical,
cost, and schedule
assessment
is an essential
assessments
are done
identifies
technology
to an acceptable
element
for each
risks must be actively
managed
of the design
Failure
design
development
process.
alternative.
required,
mode
A technology
along
throughout
development.
analyses
assessment
with the risk associated
and
Active
risk
risk/consequence
for each
design
with maturing
alternative
the technologies
level.
In the compartmentalization
process
described
coupling
between
design
functions
and between
proceed
at design
function
sublevels
such as structures,
However,
this assumption
nical disciplines.
above,
discipline
results
the
intent
functions.
is to take
This approach
propulsion,
avionics,
in a suboptimum
design
advantage
enables
of weak
the design
etc., and by the various
from two standpoints:
to
tech(1) The
total system is not optimized
since the design is consummated
at the element, subsystem
and component
level. In other words, the assumption
is that if all the parts are optimized,
when they are put together
the
system
will be optimized.
elements,
subsystems,
truly
optimized
accomplished
due
that this is true
depends
and components.
(2) Elements,
subsystems
to the
levied,
to make
The
The
degree
constraints
the system
compartmentalization
process
of tasks. An orderly
set of clearly
discipline
specific
or multidisciplinary,
At the system
as the
the coupling
and components
trades
and
design
functions
As illustrated
also
facilitates
defined
the allocation
discipline
tasks
and they must be timely
level,
design
and interface
all of the discipline
design
attributes
by the discipline
in figure
of the design
results
activities,
requirements,
design
aspects
etc.; interface
process
design
(assembled)
to achieve
of technical
integration
requirements
uncertainties,
mitigated
and managed;
verification
is adequately
achieved,
Design
and
the
minimized;
and all issues
tasks can be
to the critical
path should
allocated
function gates.
in conjunction
and subsystems.
functions
via trade
the launch
to the
It is most
with the
all certification
for each
vehicle
subsystem.
The
with the balancing
assembly.
design
minimized;
During
attributes
the
satisfy
accounted;
risks minimized,
requirements
resolved
results
In the ideal situation
are appropriately
and margins
and concerns
of design
studies
are to ensure
are met; interactions
sensitivities,
System
etc.,
These
are subsequently
the design
are included;
4.3.2
be
is the re-integration
functions
nonlinearities
constraints
must
functions.
significant
and operational
that
of requirements,
(their association
functions,
to support
by the system
are integrated
the major
constraints,
functions,
are integrated
be integrated
act. Then all the subsystems
re-integration
9, a key aspect
discipline
function
would
of the
acts
must be developed.
requirements
and is then reinforced
from the compartmentalized
each
are never
balancing
design functions,
and these allocated requirements
lead to metrics for the design
efficient and effective when the system design function develops the requirements
other
between
themselves
work.
definition
be determined).
as well
upon
defined;
flight
and documented.
Function
function.
Shown in figure 29 is the design process technical
integration
with a focus on the system design
The illustration
delineates
the relationship
between
the system design function
and the other
design
functions.
decision
discussed
In addition,
gates required
in this section.
it shows
to develop
the work/information
and
assess
the system
flow process
attributes.
that is supported
The
details
by key system
of all the above
are
51
System
Aerodynamics
Trajectory/G&N
Control
Structures
l
Thermal
Propulsion
Avionics
T..._. .................
Materials
Manufacturing
Other
Figure
The
process
technical
vehicle
process
i.e., build,
test,
however,
because
of the system
complexity,
challenging
number
and depth
of technical
disciplines,
etc.,
achieve
design
are inputs
efficiency
to control
Note:
as practiced
integration--system
a design;
achieve
launch
29. Design
and technical
analyses,
The systems
control
design
from all the other engineering
is sequential.
and fix a product
function
design
performance
outputs
planes
product
that satisfies
all the system
process
in detail,
but provides
a top-level
4,3.2.1
process.
System
Design
Function
Plane.
all the other
requirements.
overview
The systems
design
the
in order
trajectory
integration
to
outputs
of results
discipline.
The
This report
does not describe
to show
key features
as they relate
function
is the overarching
that ties together
design
function
key features
of the systems
design
function
along
with the associated
and subsystem
connectivity
This figure
will be referred
to as the system
plane.
The systems
function
design
try" to
vehicles,
and environments,
engineering
ing activity
52
results
and
sequentially
technical
by the systems
"cut
For launch
discussed,
formal
a verified
design
as previously
that involves
the system
the total vehicle
has evolved
to loads, etc.
goal is to deliver
design
one could
satisfactorily.
are inputs
supported
function.
requirements
process
For example,
is a process
function
Conceptually,
it operates
the design
fidelity.
analyses
until
design
interface
are shown
must ensure
to
engineer-
activities.
in figure
The
30.
that the design
conceptbecomesformally integratedasa balancedsystemproductthathasbeenvalidatedto satisfyall the
top-levelsystemandall otherengineeringdesignfunctionrequirements
andconstraints.Top-levelsystems
requirementsandconstraintsaredeveloped,analyzed,tested,balanced,formally integrated,andvalidated
by the systemdesignfunction.All otherdesignfunction requirementsand constraints,in contrast,are
developed,analyzed,tested,balanced,informally integrated,andvalidatedwithin andbetweenthe other
designfunctionsandthenformallyintegratedinto thesystemsdesignprocess.Mostof thetop-levelsystem
requirementsandconstraintsarederivedfrom the given missionstatement,while othersaredetermined
from experience.The requirementsand constraintsderivedfrom the mission statementare somewhat
inflexible. The major top-level systemrequirementsare performance,cost, schedule,TRL constraints,
reliability, safety,andoperability.
Top-Level
Requirements
andConstraints
System
Philosophy
Procedures
Criteria
System
Architectu
re
System
Parameter
Matrix
andUncertainties
I
• Performance
]lanceAllocations
• Cost
• Reliability
(Iterateon Systemand
BsignFunctionPlanes) • Safety
• Operability
• Schedule
• TRL
(
System
]
Attributes
r
System
Analysis
andDefinition
• Performance
• Cost
• Reliability
• Safety
• Operability
• Schedule
• TRL
• Performance
• Cost
• Reliability
• Safety
• Operability
• Schedule
• TRL
Figure
Throughout
the duration
and refined.
In addition
architecture,
certain
30. System
of a project
function
all the requirements
to the requirements
philosophies,
design
and
procedures,
constraints,
criteria,
plane.
and constraints
are continuously
assessed
the project
also develop
the system
and ground
The latter are flexible
and meant
as guides for the engineering
development.
Subsequent
to the above, the associated
system
matrix with associated
uncertainties
is defined.
The system architecture
and its associated
parameter
parameter
matrix
with
uncertainties
are determined
functions.
The
system
architecture
is then
in conjunction
evaluated
attribute
of performance,
associated
with
constraints,
philosophies,
procedures,
criteria,
rules.
must
with all the other
engineenng
design
process.
The
must
meet
requirements,
and
refined
throughout
the
system
architecture(s),
and ground
rules.
the
Other types
of system
design
the
analysis
resulting
(e.g., cost,
53
reliability,
attributes.
etc.) are conducted
for the architectural
As concepts
are being selected
(in some
concept(s)
situations
to determine
those remaining
system
there can be more than one concept),
requirements
relating to the most promising
concepts
are allocated
to all the other engineering
design
functions.
These allocations
include the design
specific
requirements
or metrics
for each engineering
design
function.
conceptual
change
Requirements
design
through
as a result
Throughout
selected
architecture(s)
constraints,
the design
process
is iterated
the system
attributes,
integration,
configuration
management;
Thus, the process
process,
the system
while
design
and discipline
procedures,
function
on each desig-n function
from
the requirements
can
all other
design
function
All the data relating
on the system
plane
to assure
rules are satisfied.
to determining
for other
to the
that
In fact,
and assessing
activities
related
to the
and management;
requirement
allocations,
system
performance
metrics;
design
and guiding
plane is iterative,
Determine
requirements
Synthesize
a candidate
design
to meet requirements
•
Analyze
the candidate
design
to determine
•
Compare
attributes
•
Modify
the candidate
•
•
Compare
Continue
functions
i.e.,
etc.
illustrated
meeting
consisting
of the following
steps:
philosophy
its attributes
(performance,
cost, reliability,
etc.)
to requirements
design
if attributes
do not meet requirements
new attributes
to requirements
iterations
until design satisfies
as discussed
and
In addition
tracking
process;
act.
and ground
responsible
•
necessary,
balancing
engineers
assessment,
redistribution;
progresses,
function
criteria,
is also
design
is decreasing.
are satisfied.
risk determination,
and
design
the uncertainty
until all requirements
the
As the design
•
If a design
design
of the engineering
by systems
the systems
throughout
or because
philosophies,
of these include
management,
updated
design.
increasing
are assessed
all the requirements,
Some
design
are continually
and
and detail
change
the entire
bases
refined
preliminary
of a top-level
knowledge
system.
are
requirements
earlier.
cannot
Throughout
requirements.
be found,
a rebalance
iterative
process,
the
or modification
all pertinent
of requirements
is
interactions
with
other
design
consideration;
are maintained.
In the past the cost of a launch
vehicle
project
usually
has not been a serious
performance
was always the primary
design metric. However,
in the next generation
of launch vehicles,
cost will be one of the most serious design considerations.
Bringing
cost into the design equation
is not
simple
in that
manufacturing,
must
be dealt
relationships
relationships
available.
effort
with using
are not available
For example,
testing,
manufacturing,
whether
time,
reliability,
etc.),
parameters.
simulations,
etc.),
facilities
etc. It should
discipline-specific
project
parameters,
to the design
the best approach
This
with the design
they be top-level
formal
contributing
relationships
would
is not possible
for most of the aforementioned;
verification,
imposed,
etc. Obviously,
design
cost associated
ments
54
judgments,
for all the various
(analysis,
materials,
it must inculcate
all the various
operations,
engineering,
etc. These
itself
however,
be to have cost-estimating
since
credible
use must be made
can be broken
(computational,
including
infrastructure,
are not all quantified
and
of those
out in terms
staff, manufacturing,
be noted
that cost is strongly
requirements
(e.g., payload,
criteria,
cost-estimating
or documentation
driven
performance,
and traceability
that are
of engineering
testing,
etc.),
by the requireturnaround
requirements.
Theseshouldbetightly controlledsincetheycanhavemajorcostimpacts.If the aforementionedwerethe
only costs,thenthejob would befairly tractable;however,thevehicledesignhasa majorimpacton cost
through operations.The vehicle combinedwith the missionrequirementsinteractsin a very complex
mannerwith operations.This canbe saidsinceit is clearthat operationshasto do with receivingthe
vehicle(usuallyby elements),processingandassembling,checkout, launching,communications(voice
and telemetry), maintainability (inspections,refurbishment,etc.), and availability (turnaround).The
vehicledesignandmarginsimpactthe launchconstraints(allowablewinds,temperatures,etc.), andthe
proceduresfor eachsubsystem.As a result,operationsand sustainingengineeringmanpowercarry a
significantcostimpact,dependingon thevehicle'srobustnessandautonomy.
Designingfor cost, therefore,implies metrics and guidelinesthat effect trade studiesbetween
operationaldesignandvehicledesign.Theseincludebut arenot limited to-• Requirements/criteria
• Robustness/reliability
• Infrastructure(facilities,etc.)
• Manufacturing
• Materials
• Maintenance
• Processing
• Assembly
• Checkoutandverification
• Launchprocedures/constraints
• Communication(voiceandtelemetry)
• Software.
Historical data help in formulating the cost models;however,cost specialistsmust assistthe
designerin understandingthe costdriversandachievinga cost-effectivedesign.Onewarning:Do not do
the costassessment
at the end.Make it a part of the up-frontdesignprocess,andtrack it on the system
plane.
All of the activitiesassociatedwith theaforementionedareaccomplishedvia formal andinformal
technicalintegrationandorchestratedby thesystemdesignfunction.This technicalintegrationis achieved
with theutilization of IxI andNxN informationflow matricesasdiscussedin section4.3.1andillustrated
in figure 27. Recall the IxI matricesareassociatedwith informationflow relatedto hardware/software
interfacesandthe NxN matricesareassociated
with informationflow relatedto thedesignanddiscipline
functions.The specificdetailsassociated
with both of thesetypesof matricesarediscussedbelow.
4.3.2.1.1 IxI Matrices.Figure27illustratestwo typesof informationflow matricesthathelp in the
characterizationof the designprocess.On the lower left is shown an IxI matrix correspondingto the
subsystemtree.IxI matricesrepresentinformationflow associated
with the subsystemtreeinterfaces.An
exampleexpansionof anIxI matrix is shownin figure31. It representsinterfaceinformationflow for the
launchvehicleandits nexttier of subsystems.
The launchvehicleis shownin theupperleft block, with its
next tier subsystemson the remainderof the diagonal.Elementson the horizontalrows containoutputs
from the entity on the diagonal,andelementson the verticalcolumnscontaininputsto the entity on the
diagonal.
55
The
structed.
first diagonal
The remaining
the tree. Along
element
diagonal
contains
elements
the top row are the interface
left column
then feeds
the subsystem
design
requirements
back the description
has accomplished
the system
(or subsystem)
are the subsystems
imposed
of the as-designed
in response
for which
the I×I matrix
(or sub-subsystems)
by the system
subsystem
to the interface
is con-
in the next lower tier of
on its subsystems.
The far
to the system;
i.e., what
interface
requirements
from above.
Inleractions Among Hardware Elements
OUTPUTS
iiiiiiii!i_iii_iiii!ili_iiii!iiiiiiiiiiiiiii
Structures
Ct.
Z
!_:_ Thermal
ii! ill
i¸'ii !i i
_ .SyStems
i_!!_iiii!_i_!_iiii_i_:_i_ii_i_i_i_!_ii_ii_i!!_i_ii!_
i_iiii_ii!ii!i_i_i_iii!_ii_i!i_i_!_i_iiiii_ii
_'
Figure
The
among
takes
remaining
peer subsystems
a clockwise
off-diagonal
along
flows
requirements
of subsystem
other
56
flow involves
elements
the common
path on the matrix.
information
occurring
31. I×I matrix
tier. Note
vehicle.
interface
requirements
that the information
In the case of peer subsystems,
(represented
A on subsystem
requirements
contain
for launch
by two
shades
B, along
of B on A, along
with B's
interface
with A's interface
interface
flow between
there
on the inset
and
descriptions
any two entities
are two concurrent
blocks).
One
description
description
interface
involves
interface
fed back
to A. The
fed back to B.
Note
subsystem
that there
that is divided
as we proceed
simple
are numerous
that
individual
down
I×I matrices,
into lower tier entities
subdivision
using
There
tiers.
is required.
handbooks,
is an IxI matrix
on the tree. Thus
the tree to its next-to-last
no further
designer,
I×I matrices.
The parts
These
standards,
but they do not have their own I×I matrices
with each system
there is an I×I matrix
or
for each subsystem
on the last tiers of the tree are sufficiently
parts
etc. These
associated
are simple
last-tier
where
enough
parts appear
they would
appear
to be designed
by an
on the lower
diagonal
of
in the upper
left element
of the matrix.
4.3.2.1.2
NxN Matrices.
the stack of design
represent
function
information
and the discipline
among
the design
flow
matrix
is shown
in figure
design
functions
and disciplines.
element
of the matrix,
On the lower right of figure
planes
32. The
example
function
functions
and the remaining
lower
is the launch
vehicle
design
an NxN matrix
resident
and the discipline
in this case
Note that the launch
27 is shown
activities
system
function
corresponding
on the planes.
functions.
vehicle
system
An example
NxN
with its associated
plane is represented
planes
to
NxN matrices
are represented
by the upper
left
on other diagonal
elements.
NxN Matrix for Launch Vehicle
1
Cost_eliabilityfOperability/Safety/OthePilities
................
OUTPUTS
_rli b
t
_il
i_e;'_' _:_
Attributes
to System
.... __
:
..........
............
220,3
TrajeCtory/
G&N
Example Matrix Entry
• Ascent Aero Heating Histories
,,,,,
Launch Vehicle Systems
Design unclions
2.0.4
Control
2.0.2 Aerodynamics
_
.0.1 Launch Vehicle System
2.-_--3.3rrajectory/G&N
_
2.0.4
_
,,,,
,,,
,,
,,
2_0.6
Control
/
2.0.5
Struclures
_
Thermal
2_0.7
2.0.6
Thermal
_
Prop
2.0.7
Propulsion
/
2.0.0
A,i;nics /
L/
2.0.9
L,"
2.0.10
Materials
./,I'
Manufacturing
y
2.( .11 Other
.,i
2:0.8
Avionics
tL/
° Entry Aero Heating Histories
• Compartment Flow Rates
• Plume Heating Environments
Structures
,,,
_"
_--";_ :
............
............
,
J'
F'_
AlloCate; Requirements. Architecture. Philosophy
2:0.2
Aero
..
_
r
...........
Materials
2;0,9
2010
Ma,u!act,ring
,,,,,7
Figure
32. NxN
matrix
for launch
vehicle.
57
The input-outputpatternis like thatof theIxI matrix;i.e., outputsof a diagonalelementareon its
horizontalrow,andinputsto theelementareon itsverticalcolumn.Thus,theentriesin thefirst row arethe
outputsfrom the launchvehiclesystemplane(allocationsof requirements,architecture,andphilosophy)
thatareinputsto the lower designfunctionplanes.This is the informationthatflows down therespective
conduitsof the stack.Theentriesin the first columnaretheoutputsfrom thelower designfunctionplanes
(attributes)thatareinputsbackto thelaunchvehiclesystemplane.This is the informationthatflowsup the
attributeconduit of the stack.The remainingoff-diagonalelementscontaininformationflow amongthe
lowerdesignfunctionplanes,asrepresented
by theroundverticalconduitof thestack.An exampleentry is
shownfor the outputfrom aerodynamics
that is inputto thermal.
Thereis an NxN matrix associatedwith eachdesignfunction stack.Thus,therearemanyN×N
matricessincethere is a designfunction stackfor every elementon the subsystemtree whosedesign
involvesmultiple designfunctionactivities.
An exampleof a relatedNxN matrix from reference2 is givenin Appendix
Inclusion
provides
of IxI matrices
locations
the design
or placeholders
process.
communication
(see section
The outputs
among
System
to the system
The decision
design
process
the requirements,
ity,
schedule,
constraints,
(i.e., yes),
tree and design
information
flow among
also suggests
efficient
Gates.
are the system
gates
description,
constraints,
are the locations
and
that must
a framework
concurrent
the design
function
stacks
the participants
in
information
and
for an electronic
interactions
(i.e., no), then there
must be another
satisfying
for the system
are the mission
attributes,
vehicle
design
failure
modes,
criteria,
is completed.
design
the requirements,
design
requirements,
and operations
where
procedures,
process
gates
in the project
operability,
philosophies,
then
with the attributes
58
to enable
with the subsystem
throughout
the
process
5.2.4).
The system
safety,
matrices
for the technical
This characterization
system
4.3.2.2
The inputs
and NxN
A.
and
function
constraints,
plan.
and associated
in figure
and system
philosophy.
There
must
be a proper
attributes,
and
the operational
the system
attributes
and
are
TRL
are shown
of performance,
compared
to the
ground
rules.
If the
On the other
hand,
if the comparisons
iteration.
This process
constraints,
etc.
is repeated
comparisons
until
33.
balance
plan.
cost, reliabilrequirements,
are
favorable
are unfavorable
the design
is balanced
Yes
• System Description
and Attributes
• Balance Between Attributes
and Requirements
• OPS Plan "How to Fly"
:No
S_stem Design
Modify Design
No
• Mission
Requirements
Yes
and Constraints
• System
".
".
Philosophy
Figure
The
systems
design
balance.
The balance
straints,
philosophies,
integration
between
results
(i.e.,
attributes)
plane.
If balance
the attributes
No '
Yes
function
33. System
must
design
provide
the project
can be accomplished
by modifying
procedures,
criteria,
and ground
the system
and other
and among
are analyzed
is achieved,
and assessed
the design
of performance,
cost,
overview
rules.
design
to achieve
operations
and enforce
proper
plan,
requirements,
con-
formal
This
is achieved
through
function
planes.
To achieve
balance,
technical
integration
on the system
informal
System
safety,
gates.
the design,
through
is completed.
reliability,
function
design
schedule,
and integration
operability,
technical
are completed
and TRL
satisfy
constraints,
philosophies,
procedures,
criteria, and ground rules. If balance
must be resolved
by modifying
the vehicle design, requirements,
constraints,
tional
plan,
or other
influencing
factors.
of the system
design
and integration
attributes,
(2) balance
between
attributes
fly the vehicle.
results
of the
The
formal
and
informal
are documented
at major
reviews.
4.3.2.3
System
Design
Tasks.
system
design
compartmentalization
and
discipline
system
The process
organizations
function
can be categorized
plan;
(3) perform
system
analysis;
specific
tasks
associated
integration
are a continual
process
of vehicle
design
tasks associated
definition
of
begins
activity
(2)
with
the
of the system
all the major
analyze,
(4) integrate
is achieved.
(I) Description
requirements,
the principals
delineate
until balance
are the following:
and overall
The definition
design
ing
design
function
activity,
is iterated
process
design
vehicle
into five major
and
for balanced
design
with the aforementioned
major
the
tasks.
that are as follows:
manage
groups
product;
process
project,
and
with the activities
After
the
functions,
associated
with
(1) Develop
engineer-
and
and (5) verify
in table
with
of how to
statement.
subsystems
as shown
of system
all the other design
The tasks
is not
opera-
The final major
in the design
mission
function,
design
groups
allocate,
and (3) operational
when
the project
levied requirements,
achieved,
the conflict
outputs
all the
the
requirements;
system
design.
1 are discussed
The
below.
59
Table
Activities
1. System
function
Interactions
tasks.
Tasks
1. Engineering design
activity plan
1. Developthe engineering organizational structure.
Program office
2. Establishformal and informal communications process.
Design functions
Discipline functions 3. Developschedule of engineering activities with associated
deliverable products.
4. Establish WBS.
5. Document and disseminate plan; include mission statement.
2. Allocation and
management of
subsystems and
requirements
1. Consult with project office to establish top-level system
Design functions
requirements, philosophies, and constraints.
Discipline functions
2. Assess and compartmentalize systems into subsystems and
elements.
3. Determine and allocate performance, cost, reliability, operability,
schedule, and TRL requirements to design functions.
4. Acquire and formally allocate discipline criteria.
5. Document and disseminate all requirements.
3. System analysis
1. During concept selection phase, define concepts; apply sizing
Design functions
program to evaluateand refine concepts; determine sensitivities;
Discipline functions
and identify new technologies required for each concept.
2. Developsystem parameter matrices and associated uncertainties.
3. Determine system derived requirements and impose discipline
derived requirements.
4. Determine system attributes from systems analyses.
5. Assess configuration and subsystems to verify conformance to
all requirements.
6. Establishfailure modes and perform a risk assessment.
7. Continue analyses throughout the project duration.
8. Document and disseminate results.
4. Integration for balanced
design product
1. Formally integrate and balance the various design function
Design functions
attributes to satisfy all systems requirements and discipline criteria
Discipline functions
2. Manage conflict among discipline functions and between design
functions to resolve all issues.
3. Perform trade studies as required.
4. Manage interfaces and changes.
i5. Document and disseminate results.
5. Verification
1. Develop verification plan (analysis and ground/flight tests).
Design functions
Discipline functions 2. Audit verification process.
3. Correct anomalies.
4. Document results.
5. Validate system during developmental flight tests.
6. Implement operational plan compatible with the verified system.
7. Document and disseminateverification plans, corrective actions,
and operational plans and procedures.
4.3.2.3.1
Task
must
be determined.
and
informal
lmEngineering
The
communication
various
Design
types
process
Plan.
Initially
the
in section
4.1.
Subsequently,
the details
the
organizational
structure
are set up consistent
the
chain
of command,
electronic
security,
and
others.
Then
upon
based
Activity
are delineated
includes
6O
design
communication
the compartmentalization,
with
system
type
of organizational
and
control,
a WBS
system
formal
must
structure
of the formal
selected.
data
This
reporting,
be developed
with
associated
tasks
to support
the activities
are then
implemented
to develop
deliverable
products.
An important
tainty.
When
system
the above
duration
feature
and Management
of Subsystems
and Requirements.
constraints,
and architecture
of the design process
as they relate to the mission
be changed
the
philosophies.
with the _eatest
statement
in addition
mission
functions.
Then
is then assessed
the system
cost, reliability,
safety,
plane
analysis.
the top-level
if there is cause and there is not a significant
The system
compromise
in conjunction
the configuration
preliminary
evolution
design,
4.3.2.3.3
cost,
a baseline
safety,
with formal
technical
architectural
concepts
the sizing
and the concepts
the activities
is established,
Task 3--System
reliability,
applying
so that
Analyses.
schedule,
operability,
integration
to resolve
along
the concepts
are refined
to achieve
the
and continues
throughout
data will be applied
are invariant;
planes
subsystems
determines
the performance,
design
functions
are coordinated.
pertains
to determining
analysis
attribute
in order to achieve
values
the performance
studies
control.
system
performance,
design.
are determined
and sensitivity
requirements
After
for the total system
a balanced
and their uncertainties
Trade
plane to the
specific criteria for formal allocation.
the process, the system plane manages
The
matrices
and design
by the system
configuration
are assessed.
they can
statement.
formal
conflict
to assess
however,
and all data are under
system
the
by consider-
that are to be allocated
of the various
top-level
must be determined
it into appropriate
and TRL design
with parameter
program,
developing
to the mission
other design planes. The system plane must also acquire discipline
All these data are then documented
and disseminated.
Throughout
A major focus of the
requirements
These
with the other design
and TRL constraints
uncer-
of the top-level
requirements
in order to compartmentalize
operability,
is important
design and operation
and uncertainty
Usually,
then
initially. The significance
and to the vehicle
results.
and
This activity
intensity
to sensitivity
from trade-study
statement
associated
with associated
Allocation
to understanding
conditions
path along
designations
and the
and disseminated.
relates
impacts
is the critical
These WBS
activities
be documented
plane
ing nominal
of the schedule
functions.
of engineering
the plan should
Task 2
potential
design
schedule
is completed,
4.3.2.3.2
requirements,
of all the engineering
an electronic
restricted
Initially,
and then,
analyses
by
are performed
to the constraints
program
guidelines.
The refined concepts
may require new technologies;
thus, these must
and evaluated.
The number of new technologies
required to achieve a concept then becomes
along
and
be determined
a factor in the
concept selection. As the refined concepts
begin to converge, the system parameter
matrices and associated
uncertainties
are matured. Then by applying those input data, systems analyses are conducted
to determine
the remaining
system
attributes;
Then
all these
results
are applied
with
all the requirements,
model
to numerically
After
focus of these analyses
technical
to assess
constraints,
rank
the number
i.e., cost, reliability,
guidelines,
the architectural
of concepts
is technical,
schedule,
the architectural
results
are eventually
to aid in the concept
narrowed
cost, and schedule
along with their uncertainties.
attributes
etc. The
concepts
has been
and operability
concept's
down,
to conformance
applied
in a decision
selection.
risk analyses
risk. The failure
in regard
modes
are performed.
are established
The
major
as part of the
risk analysis.
The total system analyses
the design
process.
The other
system analyses. The objective
reduce the uncertainties.
These
delineated
design
above are continued,
functions
provide
attributes
and the system attributes
of their
of the analyses is to improve the quality
data are applied as technical performance
subsystems
refined throughout
as input
to the total
of the values of the attributes
and
parameters
that are used to track
61
theprogressof the design
and to make
documented,
and disseminated
controlled,
4.3.2.3.4
and formal
Task 4--Integration
technical
the technical
numerous
integration
integration
for Balanced
to achieve
on the system
plane
integration
is between
all the design
a balance
of the attributes
among
discipline
criteria.
and between
balance,
sometimes
issues
resolved.
of changes.
In addition,
disseminated
by the system
Task 5--Verification.
design
function,
and it is supported
tially,
verification
test (ground/flight).
accomplished
discovered,
corrective
action
changes
redesign
are required
Aerodynamic
function
attributes.
The
plane.
to satisfy
The focus of the integration
all the requirements,
to manage
through
must control
and manage
all system
among
informal
design
integration.
all changes
interfaces.
All these data must be documented,
is
constraints,
conflict
be resolved
and manage
formal
as the
These
inter-
controlled,
and
is the responsibility
of the system
by all of the other design
functions
and the discipline
functions.
Ini-
simulation,
or
The verification
of the system
plane
and discipline
is required.
The
corrective
action
must
or an operational
All of these
When
This
are
by redesign
The results
of these
tests.
If significant
anomalies
on the system.
These
is place
are required
process.
anomalies
verified.
flight
constraint
results
the verification
functions.
can be accomplished
be subsequently
from developmental
by analyses,
to audit
functions
is obtained
Design
can be accomplished
design
to be documented
or by
activities
occur,
corrective
and disseminated.
Function
between
the design
34. This
process
illustration
functions.
technical
depicts
the other
design
is supported
by key
aerodynamic
decision
aerodynamic
attributes.
The details
of all the above
62
and
the system
to
activity
is required
in figure
informal
pertains
other
to be verified.
The connection
tion is delineated
facilitates
verification
The corrective
action
and disseminated.
The final verification
then a corrective
The system
are developed.
with the
requirement
changes.
must be documented
plane
are
integration
it is required
also control
resolution.
It is then the responsibility
is usually
4.3.3
it must
results
The informal
among
that cannot
plane
These
plane.
4.3.2.3.5
plans
balance
The system
may or may not be part of the conflict
The system
product.
functions
process.
function.
and the system
to resolve
conflict
is being
planes
the design
To achieve
a multiplicity
faces
to attain
the design
Product.
design
disciplines
This may require
design
Design
a balanced
to obtain
functions
throughout
by the systems
technical
and
decisions
In addition,
gates
integration
and the aerodynamic
the relationship
between
it shows
the work/information
that
required
are
are delineated
to develop
in this section.
design
the aerodynamic
funcdesign
flow
process
that
and
assess
the
AERODYNAMICS
System
Aerodynamics
Trajectory/G&N
Control
Structures
Thermal
Propulsion
Avionics
Materials
Manufacturing
Other
Figure
4.3.3.1
34. Design
Aerodynamic
process
technical
integration--aerodynamic
Design
Function
Plane.
This
34 and
its connection
aerodynamic
design
function
delineated
aerodynamic
design
function
interacts
tures,
thermal,
allocated
ments
and control
through
design
formal
and constraints
established
aerodynamic
is initiated
where
significant
aerodynamic
informal
However,
with the system
the aerodynamic
procedures,
analytic,
through
functions.
integration
include
in figure
criteria,
empirical,
parameters
discussion
integration
mainly
design
function
cost,
and methods.
numerical
(CFD),
of the
26. The
with the trajectory/G&N,
struc-
and constraints
etc. They
require-
the aerodynamic
design
and test methods
are applied
to determine
uncertainties.
Initially,
are used
in the sizing/trajectory
process
to support
system
the aerodynamic
program
performance
are
are assessed
Subsequently,
They
are determined.
throughout
features
(see fig. 26 and 35). These
the design
coefficients
and updated
the
in figure
schedule,
associated
refined
describes
requirements
and
moment
function.
to the stack
the aerodynamic
configuration,
design
with
process
the
force
and
and are continually
analysis.
The
steady
aerodynamic
environments
are the basis from which localized
loads and compartment
venting
are determined.
The unsteady
aerodynamic
environments
consist of determining
aeroelastic
pressures
stability,
acoustics,
environ-
overpressure,
ground
winds,
ment consists mainly of the radiation
from the external flow over the launch
also
be determined.
and buffet
design
parameters.
The
aerodynamic
heating
heat flux from the engine plumes and the convective
vehicle during ascent and reentry. The plume electron
All the aerodynamic
parameters
and
their
uncertainties
heat transfer
profiles must
are implemented
into the
63
design
process
in an iterative
the
system
manner
allocated
from
constraints
are modified
to achieve
plane.
integrated
by the system
plane
until
In some
overall
or when
design
attributes
must satisfy
figure
35. Finally,
the aerodynamic
there
is convergence
situations
the
with the requirements
allocated
aerodynamic
balance.
This can occur
when
the physics
of the situation
dictates.
the requirements
and constraints.
parameters
all other
Eventually,
are verified
Aerodynamic
Configuration
U
Procedures
Criteria
Aerodynamic
Approach
U
the aerodynamic
in flight
shown
in
experiments.
Informal
_
Integration
5
H
Aerodynamic
Parameter Matrix
and Uncertainties
Design
• Analysis
Aerodynamic
• Test
___
and
are formally
with the gate
_
Aerodynamics
Requirements
and Constraints
constraints
requirements
disciplines
This is delineated
and their uncertainties
and
Aerodynamic
Force Coefficients
Moment Coefficients
Yes ,_/'N_....._
Aerodynamic
Environment
• Localized Loads
No
• Venting
(Stop)
T
Unsteady Aero
• Aeroelasticity
• Acoustics
• Overpressure
• Buffet
(Iterate)
I Aero Attributes
I ° Stability
• Force/Moment Coefficients
Aerodynamic
Heating
• Environments
Special Analyses
and Tests
Figure
The
reference
aerodynamics
2 is shown
of aerodynamics
integration,
tainties,
connectivity,
design
design
connectivity,
64
function
functions
and the output
and
and
shown
induced
The
in figure
procedures
The focus
along
diagram
associated
process
correlation
35 is to illustrate
attributes.
NxN
plane.
design
is a direct
and criteria,
activities
and outputs
function
environments
that are accomplished
design
discipline
products.
of the inputs
design
36. It can be seen that there
and constraints,
36 is the aerodynamic
delineation
parameters
in figure
requirements
major
35. Aerodynamic
formal
parameter
flow
and
matrix
informal
discipline
along
of the aerodynamic
design
process
of reference
2 (Appendix
with the aerodynamic
requirements,
technical
process.
uncer-
with associated
shown
in figure
inputs,
outputs,
A) is representative
design
from
35. The focus
and associated
by the aerodynamic
with the corresponding
diagram
with figure
of further
i .Requi,oment,
k
Program/Project
• Concepts
L
_
"
• Constraints
• Mass Properties
Aerodynamics
Ascent Aerodynamics
External Pressure
Protuberance Airloads
Aero Coefficients
• Light Operations
Stability Derivatives
Inputs (One-Way)
• Natural Environments
N
Launch Overpressure
Ascent Acoustics
B
E
Entry Acoustics
1
Inputs/Outputs (Two-Way)
• Vehicle Configuration
and Structural Design
• Performance and Trajectories
Structural Analysis
• Thermal
• Vent Location and Sizing |
• Compartment Pressures _
.Ventino -- b
• Compa_rt_nt
Parachute Design/
Requirements
How Rates _
I Parachute Analysis
l
System Requirements
(GenericActivities)
r
Hazards
_nefits Reliability
Operability I Maintainability
Software
(S/W)_
Server
;ost/Makeor f ;ourcesRequirement.,Test
RequirementsjAIgorithrnsI Needs
_uy
IL ization
:hnical
Sizing/
Conceptual
Aaterials/
>artsList
scriptions Confgurat on
Sketches/Layouts
• Safety
• Reliability
• Cost
These
Figure
36. WBS
inputs/outputs
show
product
flow of figure
p|ishing
specific
requirements,
_
Acoustics/Overpressure
Aerodynamics
Acoustics/Overpressure
Venting
Ascent Aeroheating
Base Heating
Entry Heating
Plume Effects
Launch Stand Effects
Requirements
Trajectory Constraints
for Heating
Plume (Electron) Profiles
Breakup/Disposal Analysis
Handling
• Electrical Power
• Guidance and Controls
Products
Entry Aeroheating
Aerothermal Test
Entry Aerodynamics
Prelaunch Wind Effects
Outputs (One-way)
• Communication and Data
• Propulsion
• Materials
Aerothermodynamlcs
Ascent Aeroheating
Ascent Plume Heating
2.3--aerodynamics
the correlation
26. The corresponding
aerodynamic
aerodynamic
design
design,
and verification.
environments.
2
other design
functions,
and
with
tasks
objectives.
and induced
are shown
The tasks
These
in table 2. These
associated
tasks
tasks
with figure
are further
they
represent
are related
the
to accom-
35 are the allocation
discussed
in section
of
4.3.3.3.
65
Table
2. WBS
2.3--aerodynamics
and induced
Inputs
environments
task description.
Tasks
Outpuls
• Projected ground rules and goals
3.4.1 Aerodesign consultation
• Launch pad geometry
3,4.2 Generateascent aerodynamics
,.Preliminary design out emold line
3.4.3 Generateexternal pressure distributions
• Ground and ascent wind profiles
3.4,4 Generateprotuberanceairloads
-Atmosphericmodels
• Launch stand ambient temperatures 3.4.5 Generateaero coefficients
3.4.6 Generateaero stability derivatives
•Protuberance geometry
•Engine placement geometry
3.4.7 Generatevehicle/stage entry aerodynamics
•Ascent trajectory sets (altitude,
3.4.8 Determine vent size and location requirements
velocity, c_,15histories)
3.4.9 Determine compartment pressures
and engine operating conditions
3.4.10 Calculatecompartment flow rates
•Entry trajectories
3.4.11 Generateascent aeroheating histories
•..Airflow history to inlet
3.4.12 Generateascent plume heating histories
•Trajectory constraints
--Mach transitions
3.4.13 Generateentry heating histories
•Structural deflections
3.4.14 Determine aerothermal test requirements
•Heating constraints
3.4.15 Specify trajectory constraints for heating
-Wall/surface temperatures
3.4.16 Generatelaunch overpressure environments
•Control weights, centers of gravity
3.4.17 Generateascent acoustics environments
•Engine dimensional and operational
3.4.18 Generateentry acoustics environments
characteristics
•Turbine exhaust definition
3.4.19 Determine prelaunch wind effects
•On-pad effluent definition
3.4.20 Determine parachute system requirements
•-,,Rocket based combined launch
3.4.21 Perform breakup/disposalanalysis
(RBCC)exhaustconditions
3.4.22 Generateplume electron profiles
--Forebody inlet performance
requirements
Tools:
•..Transition roach number
• Computer codes: CEC/-IRAN72,SPF/2,StRRM,RAMP2,
•Vehicle integrated OPSconcept
RAVFAC,BLIMPJ, MOC, SPP, LANMIN,MINIVER,Various
and requirements
CFDcodes, etc.
•Hazard analysis
• Wind tunnel data
•Failure mode effects analysis inputs • Historical ground and flight test data base
--CIL inputs
4.3.3.2
Aerodynamic
in figure
Gates.
plus there are interactions
attributes,
and they must satisfy
shown
with
the gate
design
needs
and
related
to each gate
reliability,
Each
integration
functions.
The outputs are the aerodynamic
force
for the aerodynamic
impacts.
aerodynamic
design
flight
experiments.
serious
operational
and
must
designer.
is complete.
impact.
moment
functions.
to specific
coefficients,
acoustics,
heating,
also be aware
of the overall
fashion.
As the design
The
proceeds,
design
aerodynamic
constraints
metrics
design
system
parameters
then become
is finally
When
This is
aerodynamic
etc. The
requirements
data
During
of cost,
environments.
configuration
begins
through
technical
the design
some of the metrics
design
plane.
and testing.
and induced
are determined
subiteration.
or a delta redesign
analyses
As the aerodynamic
The metrics
These
design function
37 relate
via discipline
function
and the aerodynamic
in figure
designers
in an iterative
This can result in another
Operational
shown
gates also converge.
design
on the aerodynamic
data are the aerodynamic
is determined
of all the relevant
gates
by aerodynamic
designer
for the various
unforeseen
66
from other design
requirements
plane
design
the system
etc. The aforementioned
metrics
with the aerodynamic
are from
e.g.,
are determined
associated
inputs
35. The decision
requirements;
of these quantities
converge,
ments
in figure
gates
that the
the system
the aerodynamic
TRL,
The decision
37. It can be seen
discipline,
this process,
• Pressure vent sizes and locations
• Moldline update including airframe/
engine design
• Vehicleascent aerodynamics
•Heating indicators
-Vehicle/stage entry aerodynamics
• Engine inlet flowfield definition
• Externalaerodynamic pressure
distributions
•Compartment pressures
•Protuberance airloads
•Acoustic/overpressure definition
•Fluid dynamic loads (buffering)
•Ascentaero heating histories
•Entry aero heating histories
•Compartmentflow rates
•Plume heating environments
•Guidanceand control
instrumentation locations
•Airloads on propulsion elements
--Engine installed thrust
--Forebody pressure recovery
and flow field history
•Aerothermal test requirements
•Plume electron profiles
•Ascent and descentpressure
distributions
•Heating and pressure
instrumentation requirements
•Sonic boom overpressure
•Test requirements to include
instrumentation
• ELV,reusablelaunch vehicle(RLV), and RBCC
•. RLVand RBCC
-- RBCConly
Key:
are shown
2
formal
targets
may change
all the gates
to
or requirebecause
of
are satisfied,
the
validated
with data
may be required
if the flight
obtained
from
data indicate
a
Yes
AeroelasticityI
AerodynamicDesign
- Configuration
- Stability
- Forceand MomentCoefficients
- Environments
'No
| ....
•
i
m
__--{
Buffeting
t...N,
o...............,,.
and
Localized
Venting _._
I
_[.No
I Aerodynamic
Analysis
Forceand I
Moment i -I /\
Yes
Coefficients_
andPressureI
,Y
Distributions] No
Loads
Overpressure
Aerodynamic
Testing
|
L.N.o................
AeroRequirements
andConstraints
Configuration
AeroPhilosophy
Yes
Aero
Heating
4.3.3.3
Aerodynamic
of the aerodynamic
the acoustic
forces
matures,
design
(see fig. 35). These
the design
Figure
37. Aerodynamic
Design
Tasks. The aerodynamic
and moments
and blast overpressure
design
more and different
process
4.3.3.3.1
matured.
function
A summary
Determination
with the support
cost
are then
gates.
metrics
are determined
for the decision
acquired
about
the configuration
and when
integration
is formal,
but as the vehicle
through
is shown
in table
functions
aerodynamic
configura-
being
significant.
design
with
can change
evolve
from
as more
other
knowledge
design
for the aerodynamic
designer.
At this point
configuration
Initially
the technical
it becomes
predominately
informal
These
attributes
flow upwards
to the system
satisfy
the requirements.
There
are some
aerodynamic
radiation
final
parameters
heating,
is
functions.
advances,
attributes
The
criteria.
design
integration.
by
and other design
vehicle
various
metrics
3.
is accomplished
along
constraints
the targets
vehicle
fashion
considerations
established
These
of launch
and are under
i.e., formal
(e.g., plume
function
of
As the
level
aerodynamic
physics
additional
and they become
at the system
design
This
the overall
and operational
and approaches
Specific
and the associated
activity
many
with
in an iterative
and Allocation.
of the system
assessment.
for other aspects
tasks
to performance,
factors,
impact
of the aerodynamic
in table 3. In addition
converge,
and with the determination
are determined
procedures
are maintained
analysis
are needed
design
the metrics
begins with the determination
parameters
as shown
the metrics
function
to be used in the trajectory
and their uncertainties
and disciplines
Eventually,
design
aerodynamic
the aerodynamics
from
gates.
for environmental
l--Requirements
design
function
to be used
Task
aerodynamic
design
environments
parameters
and continually
tion is determined
I
ignition
control.
that are not allocated.
overpressure,
until
the
plane;
The configuration
and others)
determine
these
parameters.
67
Table3.Primarytasksfor aerodynamicdesignfunction.
Activities
Interactions
1. Requirements
determinationand
allocation
2. Aerodynamicdesign
4.3.3.3.2
groups
System
Control
Trajectories
Propulsion
Structures
Thermal
Naturalenvironment
1. Acquireallocatedrequirementsand constraintsfrom system
and interact, formally and informally, through allocation process.
2. Obtaindefinition of configuration.
3. Establishprocedures,criteria, and approaches.
4. Setupdiscipline specific criteria as the metrics for decisiongates.
5. Communicatethrough formal and informal integration process.
System
Control
Trajectories
Propulsion
Structures
Thermal
Naturalenvironment
1. Developaerodynamicmodels to determineforce and moment
coefficientsand steadyaero environments.
2. Developmodelsto determineunsteadyaerodynamicand heating
environments.
3. Establishall input dataand determineaerodynamicdesign.
- Provideaero parametermatrixand uncertainties.
4. Communicatewith interactingdisciplinesto resolveunacceptable
conditions. Resolveinformally if possible.
5. Formallyintegrateaeroattributes.
6. Documentattributes.
1. Perform aerodynamictests to verify force and moment
System
Control
coefficientsand steadyaero environments.
2. Perform specialitytests to verify unsteadyaerodynamic
Trajectories
and heatingenvironments.
Propulsion
Structures
3. Updateall input dataand refineaerodynamicdesigndata base
Thermal
using test data.
Natural environment
- Refineaero parametermatrix and uncertainties.
4. Communicatewith interactingdisciplinesto resolve
unacceptableconditions. Resolveinformally if possible.
5. Formallyintegrateaero attributes.
6. Updatedocumentedattributes.
7. Validateaerodynamicdesigndatabaseduring developmental
flight tests.
3. Verification
aerodesigner
Task
2--Aerodynamic
with continuous
as shown
formal
in table 3. Initially,
their uncertainties
are determined
are conservative.
As the configuration
achieved
via
technical
integration
adversely
affect
the attributes
resolved.
After
resolution
design
function.
documented.
Finally,
68
Tasks
Design.
and informal
empirically
the
technical
in order
more
modeling
and
to ensure
Usually
wind
the estimates
tunnel
testing.
attributes
features
are formally
and
the
parameters
of all these
and
quantities
of the parameters
The
attributes
All unacceptable
by the
with the appropriate
aerodynamic
determinations
that the aerodynamic
aerodynamic
is accomplished
interactions
and heating
accurate
functions.
the aerodynamic
significant
design
integration
from databases.
converges,
of the other design
is achieved,
aerodynamic
all of the steady, unsteady,
mathematical/numerical
continues
The
formal
and
do not cause
conditions
integrated
aerodynamic
are
informal
conflict
are required
or
to be
with the system
attributes
are
4.3.3.3.3
addressed,
table
Task
3--Verification.
the verification
3. Tests
of the
activity
is achieved
(flight)
configuration
final
aerodynamic
parameters
accomplished
to determine
In order
and determine
to ensure
with full cognizance
are
the uncertainty
parameters
that
that
all requirements
of the appropriate
accomplished
associated
are questionable
and
and
to validate
constraints
groups
the
are
as shown
already
with those
parameters.
Tests
where
associated
uncertainty
the
in
published
are also
is
unknown.
After
uncertainties)
all testing
is completed,
are reassessed
and refined.
design functions.
Subsequently,
assessments
and documentation.
lead
to a redesign
aerodynamic
database
final validation
flight-test
data are compared
function. If serious differences
The
associated
tasks
with
complementary.
aerodynamic
Then those
delineated
attributes
results
constraint.
is augmented
is achieved
parameter
are informally
When
all of the
with all the newly
during
in table
2 from
design
reference
function.
matrix
integrated
with the appropriate
and these
are design
aforementioned
phase
function for final
level. This could
is completed,
configuration
flight-test
and associated
dependent
the
data.
of the program.
The
that are documented
by the systems design
or an operational
constraint must be enforced.
2 correspond
A comparison
It can be seen from table 3 that the emphasis
and verification;
acquired
the developmental
to the aerodynamic
attributes
occur, there must be a redesign
the aerodynamic
design,
(i.e.,
the results are formally
submitted
to the systems design
If there is conflict,
it must be resolved
at the system
or to an operational
design
The
the aerodynamic
is associated
function
to the discipline
to table
3 indicates
with allocation
specific
specific
tasks
that the tasks
are
of requirements,
activities.
69
TRAJECTORY/G&N
System
Aerodynamics
4
Control
Structures
4
Thermal
Propulsion
4
Avionics
4
Materials
Manufacturing
Other
Figure
4.3.4
38. Design
integration--trajectory/G&N
design
Design
Functions
The connection
between
the design
process
technical
integration
in figure
38. The illustration
depicts
the relationship
design
are delineated
functions
processes
and the other subsystem
that are supported
the trajectory/G&N
4.3.4.1
interact,
attributes.
and their design
payload
and propulsion
The details
Function
are shown
characteristics
are needed
such as limits
on acceleration,
separation
if the system
loads,
targets,
requires
thermal,
dynamic
or reentry/recovery
them.
An initial
orbital
the work/information
to develop
pressure
targets
definition
pounds
to which
(flutter),
must
design
that determines
the desired
targets
flow
and assess
in this section.
39. Trajectory
activity
design
the trajectory/G&N
The trajectory/G&N
in figure
to achieve
to specified
between
it shows
are delineated
the design
functions.
and the trajectory/G&N
gates that are required
Plane.
together
and includes
are payloads
In addition,
decision
of all the above
Design
functions
requirements
the trajectory
functions.
performance
performance
of abort targets,
design
by key trajectory/G&N
Trajectory/G&N
encompasses
70
technical
Trajectory/G&N
functions
mass
process
closely
in this description
what
basic
to orbit. The
are added
constraints
complication
as intermediate
of the trajectory
vehicle
fundamental
vehicle
etc. The additional
be included
is made
disciplines
points
on
and guidance
approach,
and
the philosophy
and
Trajectory
optimization
programs
function
and constraints.
Initially,
uses simplified
parameters,
are used to determine
including
trajectories
this is done deterministically
feasibility,
then with increasing
balance constraints
are included
determination
pertinent
their
uncertainties,
that optimize
with simplified
are
identified.
the appropriate
objective
models
to establish
fidelity,
incorporating
appropriate
parameter
uncertainties.
for asymmetrical
configurations.
In early conceptual
design,
representations
of propulsion,
aerodynamics,
mass,
winds,
basic
Moment
trajectory
and air density.
Informal '_
ntegration ;:
Trajectory/
Guidance
Definition
Requirements
and Constraints
_ (Stop)
(Stop) y
.
[TrajectorylGuidance[
[
[[
[_'1
[
[]
I es.j .o
Ves .o
i
Achieving
iterated
until
the successive
[
[ and Uncertainties
I
[ Special Constraints
•Thermal
" [,Flutter
I" Loads
I
I • Other (Separation)
the
attributes
of the vehicle
performance,
design
trajectories
maximum
expected
values
using dispersions
also produces
reserves,
and fuel bias definition.
Performance
G&N
System
Error Definition
function
performance
definition,
As the vehicle
design
reserves
and environment
models
of certain
performance
design
to define
reserves
variables
such
as loads
iteration
parameters
are
proceeds,
trajectory
functions
and subsystems.
to higher
(partial
requires
trajectories
the latter represent
sensitivities
usually
and system
process
by the other
are developed;
[
plane.
constraints,
experienced
and performance
and dispersed
Analysis
design
The trajectory
approach
variables),
mechanics
t
to orbit with adequate
satisfactory.
flight
*
payload
are
definitions
,_
39. Trajectory/G&N
refinement
]
Algorithms
Sensor Requirements
• Error Budgets
Figure
with the system.
._
• Payload
• Design Ref. Trajectory
Flight Per.
Reserve
i :Trajectory
Design
• Separation Char.
Throttlin_ Profile
It uses improved
produce
Approaches
I Trajectory Inputs
Determination
Trajectory
desired
parameters
follows
that
I
[Trajectory/Guidance [
Parameter Matrix _
[
(lterate)l
G&N System Attributes
• Sensor Requirements
• Computer Requirement
Accuracy (Errors)
• Cost Factors
• Reliability Factors
• Complexity
trajectories
[
[
_
(Iterate)
l
Trajectory Attributes
• Payload
• LoadIndicators
• ThermalIndicators
• TrajectoryCharacteristics
• Constraintsand
Requirements
of vehicle
Philosophy
Criteria
Procedures
(time
fidelity.
or aerodynamic
derivatives),
histories
Both
time-consistent
design
of
nominal
trajectories
heating.
flight performance
71
Theperformance
andtrajectories
processflow diagramandWBS
duced in figure 40 and table 4, respectively.
The process
with the former
and connectivity,
emphasizing
son of requirements
inputs/outputs
and attributes
trajectory
time histories,
sentative
of further delineation
function
process.
to achieve
both nominal
and dispersed.
2 are repro-
with the flow diagram
of figure 39,
flow is consistent
convergence.
and the latter emphasizing
Outputs
are indicated
The NxN diagram
of the inputs and outputs
task chart from reference
associated
the iterative
for payload
of reference
The tasks given on the WBS chart are expanded
performance
2 (Appendix
with the performance
compari-
A) is repre-
and trajectories
in more detail in section
and
design
4.3.4.3.
Internal Flow
Requirements
_[
• Program/Project
• Mission Requirements
_
I
_-Vl
• Constraints
I
_._,_
Reference Trajectories
Design Trajectories
Vehicle Partials
I
I
• Reference
• Trajectories
Inputs (One-Way)
• Natural Environments
• Cost
Outp(as(One-Way/
• Ground Operations
Inlet Trade
Versus Thrust/
Performan ce
• Mass Properties
• Propulsion
• Communications and Data
Handling
• Flight Operations
• Safety
• Reliability
Figure
G&N
system
configuration
and algorithm
performance
iterated
until
system plane.
system
in the figures
72
2.2--performance
design
follows
is hypothesized
at acceptable
close
more
similar
flow diagram.
to other
design
functions
to determine
its performance.
cost and complexity.
Uncertainties
(errors)
as inputs
analysis
to margin
meet
requirements,
and design
activities
2. The G&N
4.3.5.1.
and reserve
process
in figure
in that a tentative
to obtain
from the analysis
The tentative
or else requirements
relief
39 are combined
flow and WBS from reference
2
In specifying
specialists
determined
determination.
shown
captured Ispeffective Iso
engine drag loss (lipspill
age) and parasitic drag
and smooth body drag
losses for RAM/SCRAM
process
with avionics
satisfactorily
in reference
a pattern
and then analyzed
G&N
in section
Shutdowr
design
is maintained
analysis
system
and trajectories
coordination
its attributes
activities
RBCC
Document: Amount of air
Hazards
Benefits Reliability I (_perabilityI Maintainabifity
3ost/MakeolResource.,RequirementsTest
S/W
Server
Buy
UtilizationFeedback
Requrements Algorithms Needs
Materials/ Technical [ Sizing/
Conceptual
PartsList
Descriptions
I Configuration
Sketches/Layouts
requirements,
back to the trajectory
* Failu re Analysis
Engine Axis
Gyroscope/Accelerator
Failure
>3(_
Flight performance
Reserve (FPR)
CZcritical
40. WBS
The G&N
• Design
Traiectories
FuelBias
Time Histories
- Acceleration
- Aeroheating
Indicators
- Attitude/Velocity
Attitude
Dynamic Pressure
_t Versus Inlet Size
(Effective)
• Vehicle Partial
• Derivatives
Inpuls/Outputs (TwoWay)
• Vehicle Configuration
and Structural Design
• Aerodynamics and Induced
Environments
• Structural Analysis
• Thermal
• Guidance and Control
Dispersions
Performance
Time Histories
Contingency Analysis*
Operational Trajectory
Flight Evaluation Best
Traiectory
• Range Safety
• Guidance or Onboard
Computer (OBC)
Presetting
• Flight Performance
(Payload Capability)
• Flight profiles
G&N
is sought
sensor
adequate
are fed
system
from the
with the control
2, therefore,
is
are included
Table4.WBS 2.2--vehicleperformanceandtrajectoriestaskdescription.2
Inputs
Tasks
3.2.1
•Mission definitions
•Initial performance
•Vehicle coordination system
•Launch pad geometry
•Project ground rules and goals
• Redundancy requests
• Preliminary design concept
and database
• Rangesafety constraints
•Atmospheric model
•Ascent wind models
Outputs
Perform trade studies on trajectory/
• Staging requirements
• Propellant requirements
• Number of engines
•Performance updates
•Entry propellant weight
•Ascent trajectory sets (altitude,
velocity, X, I_ histories) and engine
operating conditions
•,,Entry trajectories
,.,,.Airflow history to inlet
•Trajectory constraints
,-..Mach transitions
configuration options
3.2.2
Develop nominal trajectories
3.2.3
Develop design trajectories
3.2,4
Assess vehicle sizing, mass properties
3.2.5
Evaluatevehicle performance
3.2.6
Developabort scenarios and trajectories
• Launch pad environments
• Engine alignment tolerances
,..,Vehicle geometry drawing
• Vehicle ascent aerodynamics
• Heating indicators
.-,Vehicle/stage entry aerodynamics
•Engine inlet flow field definition
•Engine installed thrust throughout
trajectory
•Qcc,QI3constraints and structural
load indicators
•Loads trajectory data
•.,,Ascent, cruise, loading requirements
•Reference trajectories and time
histories
• Max Q
•...e_,airflow
•-,.Ascent, cruise, landing requirements
• Propellant load versus time
• Burn times
-Residuals at main engine cutoff, etc.
•Vehicle mass versus time
••Wall/su rface temperatu res
•Heating rate or temperature
indicators
•Autopilot definition
•Guidance system inputs
•...Modified autopilot to reflect
a control law for airflow to inlet
•Control surface mixing logic
•Control weights and current weights
Key:
Trajectory
requirements,
•Antenna range data
•Launch mission rules
•Vehicle breakup and disposal analysis
•Launch commit criteria
•Launch corridor
,-..Landing corridor
•Abort alternate mission analyses
• Eventtimelines
• Software--Dynamic simulations, program to optimize
simulated trajectories (POST)
Gates.
along
assumed
system
limitations
thermal
indicators,
abort
identifies
pertinent
nominal
and
designers
work
especially
mance
Tools:
• ELV,RLV,and RBCC
•.. RLVand RBCC
,,-- RBCConly
4.3.4.2
targeting
• Isp(flow rates)
• Usable propellant requirements
•Flow rates
•System dispersions
....(_ inlet
,--,Derived air volume
such
as staging
the distributions
in the early
design
in figure
where
from
dynamic
other
optimal
performance
stages
to iterate
the basic
with acceptable
margins,
considering
41. Indicated
gates
properties,
variables
three
the excess
maximum
load
the trajectory
constrained
variables.
aerodynamics,
and
satisfying
trajectories,
The
or
designer
both
trajectory
and propulsion,
of the vehicle
in order
to attain
perfor-
variations.
Trajectory
decision
gates
parameter
possibilities:
margin
performance
to those
pressure,
disciplines,
and produces
the system
plane is provided
performance,
sensitivities,
and timelines
are provided
(3) performance
shortfall.
In the third case,
collaboration
where
payload
trajectories
of trajectory
structures/mass
consider
by top-level
maximum
with appropriate
and their uncertainties
to identify
specialists
(unlikely),
conditions,
etc. Working
with
are shown
iteration;and
is driven
limit the acceptable
closely
requirements
shortfall,
design
which
targets,
parameters
dispersed,
Trajectory
with constraints
(1) Surplus
for other tradeoffs;
to the system
performance
(2) neither
plane
with the above
margin
surplus
without
design
nor
further
functions
73
attemptsto find an achievablefix for the problemwithin the respectiverequirementsandconstraints.If
successful,anoutputlike the secondcaseis made,but,if unsuccessful,the issuegoesto the systemplane
for relief or rebalanceof requirementsandconstraints.
_ _
-_
_-,v,_
_
.... _'_"
Go to System with
Parametric Information
to TradeTrajectory
YES ,.
"
Margins
NO
.,_0
/
Parameter Matrix
and
Mass Propertie_
Uncertainties
__
(__.c_
k,_Design _'
Parameter Matrix I
Trajectory
and
I
Design
]
t
"1
I Uncertainties
I
I Go to System with Trajectory
A, _
IA.ributes
//Requirements_
%,_nd Constraints//"
YES
J°Performance
"1 Sensitivity of Performance
"_atisfie_"
I • and Constraints
"_
Go to System
I
Mission Timeline
/%ggested'_ YEsl Interactwith I _¥ES_
Propulsion
I
Parameter Matrix I
and
I
Uncertainties
I
(_
Changes
_1
/_lDesign
_
I
[toAssessRxes
I
x4Q_
4.3.4.3
Trajectory
conceptual
feasibility
to perform
mission-specific
responsibility
pertinent
constraints
part of design
in table 5.
element
trajectory
Task
of conceptual
of concept
fundamental
the trajectory
concept,
design
feasibility
operating
Determination
the trajectory
screening.
Working
philosophy
plane.
from
information,
with other
or by discussion
design
Initial estimates
their respective
disciplines,
I
design
function
is a part
of the earliest
the design
process
and continues
in the operational
phase.
The primary
payload
performance
subject
to all
and
and margins,
flight
performance
reserves,
vehicle
that evolve
concurrently
with and as a
and iterative
process.
and Preliminary
function
accommodation),
Task summaries
Perfonrmnce
(referred
trajectory
top-level
are shown
Estimates.
to as "trajectory")
as part of a small group,
(e.g., abort
I
I
gates.
that maximize
launch
interactive
and Constraints
Mission
Timeline
through
determination
performance
a highly
1---Requirements
design,
its output
time histories
on a typical
and constraints
from the system
mental conditions
are obtained
74
matures
payload
of constraints
function
trajectory/performance
It iteratively
and to identify
make
4.3.4.3.1
part
The
Go to System
for Resolution
I
design
trajectory/performance
is to determine
fuel bias. The multiplicity
early
Tasks.
activities.
Sensitivity of
Performance
7
_0
for
Go Resolution
to System
41. Trajectory
All Changes
Performance
Functionsl")_A_hi_.-ahl_/"_-'_
NO
Figure
with Trajectory
:Attributes and
obtains
payload
In the
is a central
the vehicle
requirements,
of weight, drag, thrust, Isp, and any special environdesign functions
and disciplines.
Using historical
preliminary
constraints
are generated.
Then,
using
Table
5. Primary
Activities
these
for trajectory
design
functions.
Tasks
Interactions
1. Requirements determination System
and preliminary performance Mass properties
estimates
Propulsion
Aerodynamics
Natural environment
1. Obtainfundamental concept, operating philosophy (e.g., abort
accommodation), and top-level payload requirement
and constraints from system.
2. Obtain initial weight estimate, drag estimate, thrust and Isp
estimates, and any special environmental input from the
respective design functions.
3. Run simplified trajectory program with initial inputs to obtain
performance (including appropriate margins).
4. If desired performance not obtained, work with small group
of representatives of other design functions to trade basic system
descriptors (listed in item 2) to converge to a solution acceptable
to all parties.
5. If trades are major, or if convergence cannot be attained,
take trade information to system for decision or requirement/
constraint change.
2. Detailedpayload
performance determination
System
Mass properties
Propulsion
Aerodynamics
Thermal
Natural environment
1. As concept matures, perform detailed trajectory simulation
and payload determination, maintaining close coordination with
pertinent other design functions.
2. Although information is more detailed and interaction somewhat
more formal than activity 1, interact with other design functions
on sensitivity and trade data to converge to acceptable solutions.
3. Interface with system to provide sensitivity, trade, and margin
information for possible adjustments to requirements, constraints
and allocations.
3. Design reference
trajectories
i 1. Obtain from thermal and loads disciplines indicator functions
Aerodynamics
Thermal
of trajectory variables, and calculate indicator values with each
trajectory run within the trajectory/system/environment
IStructures (loads)
Natural environment
parameter space.
2. Work with each respective discipline to select its design reterence
trajectory from the total set, representing a time-consistent
trajectory which maximizes the appropriate indicator. Provide
these to the disciplines as analysis simplification tools.
3. Continue to consult with the disciplines as the design matures
to makeany necessaryadjustments to the design reference
trajectories.
4. Verification
System
Aerodynamics
Natural environment
Propulsion
Structures
initial
inputs
determined.
functions
tion
tasks
and
acceptable
is provided
with
If desired
a quick
performance
disciplines
to trade
to all parties.
to the
system
turnaround
program,
is not obtained,
basic
If the trades
plane
1. Develophigh-fidelity simulation to accommodate test-verified
models.
2. Obtaintest-verified models of major contributors to trajectory/
performance, such as propulsion system characteristics,
structural mass, etc.
3. Using this simulation, verify trajectory design over range
of expected parametersand conditions.
4. Obtain final verification from flight test.
system
descriptors
are major
for screening
estimated
payload
the trajectory
(the
design
inputs
or if convergence
decisions
or revision
performance
function
listed
cannot
above)
works
and
margins
with
other
to converge
be attained,
trade
are
design
to a soluinformation
to requirements/constraints.
75
4.3.4.3.2
Task
2--Detailed
functions,
trajectory
parameters
as the design
progresses.
(uncertainty)
parameters
obtained
natural
environment
group.
Likewise,
performance
imposed
on trajectory
• State
Payload
accommodates
vector
requirements
orbital
targets
staging
states
dictated
• Structural
loads
• Maximum
• Maximum
dynamic pressure
acceleration
(represented
include
nominal
structures,
and aerodynamics
planes,
constraints
are refined.
derive
models
from numerous
and dispersed
and from the
The constraints
other
disciplines
recovery,
and disposal
through
interaction
design
environmental
which
are
and include--
of stages
by load indicators)
hinge
• Aeroheating
(represented
by thermal
• Abort
and limits,
if pertinent
targets
and
by clearance,
• Aerosurface
• Communication
to other
of vehicle
and system
throttling
Similarly
descriptions
and environmental
from the propulsion,
and engine
Determination.
detailed
The vehicle
shaping
• Intermediate
Performance
increasingly
moment
limits
and range
safety
indicators)
constraints
• Etc.
design
Trajectory
identifies
functions
and disciplines.
Detailed
trajectory
histories,
payload
updates
and environmental
direction
of design
converge
to acceptable
parameters.
and
are used
performance
Sensitivity
to determine
reserves/fuel
are derived
trajectory
bias
and
to guide
trade
are made
among
the design
functions
The
trajectory
plane
interfaces
with
system
adjustments
to requirements,
for possible
the
respective
throttling
to accommodate
trades
information
data
with the other
Informal
solutions.
margin
constraints
programs
and flight
improvement.
trade,
these
optimization
performance,
vehicle
sensitivity,
and
time
variations
in
and point
the
and disciplines
to
studies
plane
to provide
constraints,
and
allocations.
A cycle
determined
is complete
for a comprehensive
variations.
Validity
be queried
and brought
4.3.4.3.3
means
Reference
Trajectories.
analysis/design
independently
in loads
that represent
the trajectory
or aeroheating.
requirements
have been
parameter
def'mition,
and program
values
fidelity
with
should
reference
trajectories
are generated
process.
Since
it is impractical
and thermal
analysis,
it is useful
as a
to include
to develop
all
refer-
parameter
set which
maximizes
(to a statistical
measure)
design
reference
trajectories
then serve
as nonlinear
time-consistent
bases for
analyses
(usually
linearized)
that include
the remaining
These
or thermal
variations.
vehicle/environmental
Design
and thermal
trajectories
meeting
to satisfaction.
the loads
loads
76
and
and margins
of the input data, constraint
parameters
ence
parameter
dispersions,
set of constraints
Task 3--Design
of simplifying
loads
trajectories,
and appropriateness
statistically-varying
detailed
when
larger
set of additional
Trajectory
obtains
variables
and calculates
parameter
space. Trajectory
from
from
the loads
indicator
values
then works
the total set to a suitable
time-consistent
remaining
basis
variables.
Monte
Carlo
desired
statistical
to develop
for the systems
to make any updates
Task 4--Verification.
analytical
propulsion
system
complete
checked.
The combined
over the range
of expected
conditions
and performance
capability.
system
System
design
synthesis
function,
to be part of the avionics
system
interfaces
interface
design
in the design
is for negotiating
with the system
plane
plane.
Top-level
requirements
greater
detail
process
involves
including
algorithms
i.e., what
outputs,
the design
software,
and
the latter
operational
requirements
G&N
decision
sensor
and software
as flowed
down
and starting
sensor requirements,
information.
Close
and
point
performance
with
plane
for G&N
(accuracy,
reasonableness
interaction
42. Primary
planes.
G&N
Before
avionics
of the
G&N
(The avionics
initially
from the system
are expanded
design.
The
helps
design
require-
the converged
delivered),
requirements
with
specifications,
information
providing
payload
is assumed
also works
system
specialists
design
to be the G&N
in figure
and operational
to be loaded.
in as
trajectory
which
G&N
weights
are modeled
will be allocated
are the
will have
structural
is taken
from the system
Outputs
is accom-
the final verification
and avionics
which
information
modes,
design
function
requirements).
and philosophy
of acceptable
design
control,
requirements,
abort
function
to consult
of key components.
test provides
design
the
trajectories.
satisfactory
gates are illustrated
cycle.
and
Flight
the G&N
the basis
must meet the gates
failure
variations.
to provide
and software
of required
then is used to verify
synthesize/analyze
mission-specific
modation
assure
specialists
the typical
testing
set of
achieved
continues
reference
and its environment
from the hardware/software
and philosophy
trajectory
and actual
simulation
the requirements
full-dimensional
approach
and performance
from hot-fire
are with the trajectories,
and specifying
to identify
by the G&N
ments;
function.
for analysis,
to the design
The vehicle
a
the large
derived
In this document,
process
matures,
trajectory
disciplines
considering
models
possible.
as distinct
reference
that make use of test-verified
and parameter
Gates.
cases,
that the approximate
As the design
of trajectory
and aerothermal
is used as an expedient
of the trajectory
as practical.
G&N
design
Verification
where
functions
to select its design
the loads
necessary
detail
4.3.4.4
discipline
or adjustments
characteristics
simulation
the trajectory/system/environment
have confirmed
simulations
are used in the verification
indicator
run within
maximum
approach
measure
disciplines
This provides
their
this approximate
run in past programs
with high-fidelity
For example,
measure.
cases
4.3.4.3.4
aerothermal
with each respective
statistical
which
Although
check
with the disciplines
plished
upon
and
with each trajectory
accom-
for sensors,
converge
and
are met.
77
Yes
Sensor
I
Reasonable n
Requirements
I
w....
G&N System
Specifications
.
u
Reasonable
Software Requirements
Sensor Requirements
Operational Information
Requirements
G&N
Software
ties
Requirements
t
............
_ .....
Acceptable
Performance
G&N
System
Analysis
• Target Accuracy
• Payload Delivery
• G&N Philosophy
and Approach
• Targets
• Staging and
Trajectory Constraints
• Failureand Abort
Philosophy
Reasonable
G&N
4.3.4.5.1
Task
mining
target
errors
of the G&N
mance
reserve
complexity.
accuracy
G&N
abort
accommodate
modes
control that adapts
must be observed.
Another
operational
78
are strong
balance
data loads
these
have
drivers.
and abort modes.
to the specific
that must
and updates
No !
in table 6. G&N
G&N
margin
works
requirements
conditions
to converge
requires
interaction
on G&N
G&N
works
with the system
on maximum
Constraints
is G&N
to attain
drive
design.
trajectory
in deter-
The potential
target
the G&N
and trajectory
pressure
on the permitted
the performance
set that determines
For vehicles
dynamic
system
with
system
perforcost and
on the best design.
effect
state conditions.
closely
in this margin
a major
be achieved
synthesis
and capability.
as part of the dispersion
assumptions
A constraint
needed
gates.
planes.
to trajectory
accuracy
balances
function
Accommodation.
are provided
on the vehicle
design
are summarized
performance
Stringent
synthesis
G&N
and control
1--Requirements
system
failure
42.
Tasks for G&N
avionics,
and payload
margins.
Constraints
capability,
Tasks.
trajectory,
_
Failure
and Abort Modes
Accommodated
Figure
4,3.4.5
and
Update
Operational
uirements
"
',,
Yes
with the systems,
o
No:
performance
that require
design
functions
may require
of engine
versus
the complexity
of expected
to
throttling
range
for the range
abort
throttling
missions.
of
Table
for G&N
function.
Interactions
Tasks
1. Requirements
accommodation
Trajectory system
1. Work with trajectory in converging to accuracy and payload
margin requirements and capability
2. Work with system andtrajectory in accommodating constraints
such as failure and abort modes, maximum dynamic pressure, etc.
3. With system, determine appropriate balance betweenperformance
and complexity of operational data loads and updates.
2. Detailed G&Nsystem
synthesis
System
Trajectory
Control
Avionics
1. Perform iterative synthesis/analysis to best balance performance
requirements with cost and operational considerations.
2. Maintain close coordination with system and trajectory as
requirements mature, with control to define initiation state
requirements and to coordinate flight control computer
interactions, and avionics for software/hardware requirements
(see below).
3. Iterate to satisfaction of requirements and constraints with an
adequatebalance of performance and cost/complexity.
3. Component and software
requirements
Avionics
Trajectory
System
1. Maintain close working relationship with avionics to keepabreast
of hardware/software state of the art.
2. During G&N system synthesis, work with avionics in
specifying component and software requirements to
provide acceptable performance, cost, complexity, reliability,
operability, and maintainability.
3. If performance cannot be achievedwith hardwareand software
that meet avionics attribute allocations, explore performance
requirement relief with trajectory and systems.
4. If resolution not obtained, take to system for top-level trades.
4. Verification
Avionics
Control
Trajectory
Propulsion
System
1. Develophigh-fidelity analytical simulations, modeling system
and environment.
2. Using simulation, verity G&N performance over full range
of parameter and environment variations.
3. Work with avionics to perform software verify and validate (v&v)
and to verify G&N performance in hardware/software test beds.
4. Obtain final verification from flight test,
is to synthesize
Task
2--Detailed
a G&N
system
constraints.
this,
The
process
performance
G&N
System
architecture
that
It is not the intent
to accomplish
nation
tasks
Activities
4.3.4.5.2
facing
6. Primary
but to note
is the
requirements
is required
with
guidance
initiation
avionics
plane
primary
usual
with
the
state
system
best
report
meets
of the G&N
in detail
the process
and
interactions.
cycle,
considerations.
planes
coordinate
requirements
activity
to describe
synthesis/analysis
and trajectory
core
requirements
and operational
and
The
the vehicle
considerations
iterative
cost
requirements
for software/hardware
of this
Synthesis.
as described
flight
as noted
directed
Throughout
above,
computer
with
cycle
while
used
toward
design
satisfying
by G&N
best
the process,
function
inter-
specialists
balancing
close
the control
plane
requirements,
and
the
coordito define
with
the
below.
79
Wheredataandprogramshavebeensubjectedto critical assessment,
satisfactionof requirements
andconstraintsandanadequatebalanceof performanceandcost/complexitydetermineadequacyof the
detaileddesign.
4.3.4.5.3 Task3--ComponentandSoftwareRequirements.Oneof the mainoutputsof the G&N
designfunction is a convergedset of requirementsfor G&N sensorsand algorithm softwarewhich is
providedto the avionicsplane.Before andduring the designprocess,G&N specialistsmaintaina close
relationshipwith hardwareandsoftwarespecialistsin avionicsin orderto keepabreastof the stateof the
artandcapability.During systemsynthesis,G&N worksvery closelywith avionicsto specifycomponent
andsoftwarerequirementswhich both meetsystemperformancerequirementsandrepresentacceptable
cost,complexity,reliability, operability,andmaintainability.The latter setof requirementsis capturedin
the systemallocationof requirementsto the avionicsplane.
If performancecannot be achievedwith component hardwareand software that meets the
avionics plane allocations,G&N exploresperformancerequirementrelief with the trajectory design
function. If resolution is not obtained,the issueis taken to the systemplane for top-level tradesor
requirementsrevision.
The processis completewhenthe sensorcomponentandalgorithmsoftwarerequirementssatisfy
both theG&N systemperformancerequirements(imposedonG&N) andthe cost,reliability, operability,
andmaintainabilityrequirementsallocatedto theavionicsplane.
4.3.4.5.4 Task4--Verification. Verificationof the G&N systemis accomplishedprimarily with
analyticalsimulations,asaugmented
with theuseof testbedsinvolving flight-type hardwareandsoftware.
High-fidelity analyticalsimulationsaregenerated
to modelthe G&N systemalongwith thevehicleandits
environmentin as completedetail aspractical.The combinedsimulationis run using the full rangeof
expectedparametervariationstoensurethatsatisfactoryperformanceis attainedatall operatingconditions
andsystemvariations.Avionics test beds use flight-type hardware and software with simulated vehicle
aspects
to confirm
the avionics
80
the correct
section).
Finally,
functioning
of the G&N
flight test provides
system
as implemented
the final verification.
physically
(as discussed
in
CONTROL
System
Trajectory/G&N
/
Control
Structures
Thermal
T_
Propulsion
!._"
Avionics
=,
Materials
.J
Manufacturing
,,........................
Other
4.3.5
Control
Figure
43. Design
Design
Function
As shown
control
design
in figure
function
technical
43, the connection
is shown.
tion and the other subsystem
process
between
The illustration
design
integration--control
functions.
depicts
the design
4.3.5.1
system,
specification
functions
design
Control
is illustrated
Design
in figure
of the control
and disciplines.
parameters,
requirements
Function
44. The
it shows
and constraints
studies
function
requirements,
is determination
of lift-off
are interpreted
design
and assess
into a form applicable
integration
the control
as represented
design
func-
attributes.
that
The
on the control
of the vehicle
control
interactions
with other design
response
and the associated
dynamic
clearances,
and the
flow process
the control
the synthesis
and necessary
and separation
technical
between
function
involves
of vehicular
function.
the work/information
to develop
The control
design
component
Also involved
including
Plane.
control
process
the relationship
In addition,
is supported
by key control decision gates that are required
details of the above are delineated
in this section.
plane
design
pogo,
to the control
sloshing,
system.
etc. First,
From
the
experience,
81
atentativecontrolsystemconfigurationis defined,alongwith thephilosophy,procedures,andcriteriathat
will be employed.The control specialiststhen identify the matrix of parametersaffecting the control
systemandtogetherwith specialistsfrom other disciplinesidentify by data or judgmentthe variations
(uncertaintydistributions)of the parameters.Nominal anddispersedstability andresponseanalysesare
run to assessthe performanceof thetentativedesign.In somecases,suchasstructuralloads, the acceptability
of the performance
design
is determined
is determined
on the structures
initially
by load indicators,
but final acceptability
of the refined
plane.
Informal_
_ilntegration
Control System
ControlSystem
Definition
Requirements
and Constraints
ControlSystem
ParameterMatrix
and Uncertainties
__..__I ControlSystem
I
Philosophy,
Procedures,
Criteria
Response
Analysis
J¢
Yes _
(Stop)
_
No
(Iterate)
Structural
Dynamics
Component
Control
Requirements
Stability
Analysis
ControlSystem
Attributes
• Response
_• Stability
• Margins
SeparationandLiftoff Clearances,
Pogo,
Special
Analyses
Sloshing,
EandTests
tc.
Figure
Structural
analyses,
are shown
but also other design
are important
design
dynamics
interactors
functions
eventual
of control
the cost, reliability,
response,
stability,
component
cost,
such as aerodynamics,
component
requirements
as converged
specialists.
The tentative
control
constraints,
or relief
requirements
from
relationship
for the control
component
attributes
are shown
as the control
etc.,
on the avionics
between
system
and
significant
is necessary
system
requirements
and operability
and margins
reliability,
plane.
and disciplines
A close
system
function
as a particularly
that have the responsibility
specification
design
on the diagram
functions
with control.
influences
82
44. Control
system
trajectories,
and propulsion
and propulsion
hardware
evolves
from this close
plane
and propulsion
attributes,
planes
the control
system
specialists
is iterated
until
its attributes
is sought
from
plane.
and software.
The
interaction
planes.
the attributes
are determined
design
the system
to the control
with the avionics
component
of the avionics
propulsion
input
Thus
and
while
of control
by the control
and the avionics/propulsion
meet
the requirements
and
In reference
and WBS
flow
2, the guidance
and control
from
2 are reproduced
task chart
is consistent
reference
with the flow diagram
and connectivity,
and the latter
functions
combined.
The process
45 and table
7, respectively.
with the former
emphasizing
in figure
of the control
emphasizing
are shown
plane,
the iterative
comparison
of requirements
flow diagram
The process
inputs/outputs
and attributes
achieve
convergence.
The N×N diagram
of reference
2 (app. A) is representative
delineation
of the inputs and outputs associated
with the control design function.
The tasks
WBS chart are expanded
in more detail in section 4.3.5.4.
aspects
As will be addressed
later, additional
activities
necessary
adequate
and separation
to ensure
lift-off
of the control
design
clearances,
to
of further
given on the
function
are to specify
design
pogo stability,
and propellant
slosh
stability.
Internal Flow
Requirements
[_
• Constraints
• Program/Project
• Concepts Design
F
W
,Constra ots
.......::':
Guidance
t 1" Contro
_
l,npuls (One-Way)
Natural Environments
• Aerodynamics and Induced
Environment
_
_
_
It_
• Mass Properties
Ill
Outputs(One-Way)
• Electrical Power
_
U
II I
Inputs/Outputs(Two-Way)
_
I
• Vehicle Configuration
Wl
• and Structural Design
IJ
Structural Analysis
_
• Performance and Trajectories IW
• Communication and Data
_
Handling
_
• Propulsion
• Safety
• Reliability
• Cost
U
IJJ
I
I
System
r---_l
system
Definition
_
J F--_'J° Design
I
I and Analysis
"----- I
Slosh
Stability
[
i
I" Pogo
I
I
I
I
_
Stability
EU
J and
_
I Requirements_
:
-_{
, Oefiniti°n
"1
I
I"Performance
..._1 Predictions
_
1_
Analysis
_
" I
I
I
• and Stability Margins
Subsystem
and Component
Requirements
I" Baffle
_
:-I Requirements_
I Definition
II
'....
k
N
I
I
lazards Benefits Reliability
Operability
.....
l Maintainability
;t/Makeor ResourcesRequirementsTest
SA_/
Server
_1
_
..................................
I
'
terials/
ts L st
Figure
2.6--guidance
45. WBS
I Products
• Autopilot Definition
• Guidance Algorithms
• Load Indicators
• Performance
UtilizationFeedback I Requirements
I Algorithms
I Needs
Technical
Sizing/
Conceptual
Descrpt ons Confguraton
Sketches/Layouts
and control
design
process
flow diagram.
2
83
Table 7. WBS
3.6.0---guidance
Inputs
and control
task description.
Tasks
3.7.1
• Projected ground rules
• Design-to-cost goals
• Launch probability requirements
• Preliminary design concept
and data base
•Atmospheric model
• Wind models (ground/ascent)
• Gust models
Outputs
• Maximum engine deflection
• Control sensor locations
Develop flight guidance and control system
strategies
3.7.2
Derive subsystem/component
3.7.3
3.7.4
Determine system performance/margins
Determine induced environments
• Control surface deflection requirements
• Autopilot definition
• Guidance system inputs
-,Modified autopilot to reflect a
control law for airflow to inlet
requirements
• Control surface mixing logic
• Slosh damping requirements
• Oc_versus O_ envelopes
• Flex-body mode frequency constraints
•Vehicle transient response to wind
disturbances
• Pogo suppressor requirements
• I-VC requirements
• Reaction control system (RCS)
requirements
• Software requirements
• Computer requirements
• Sensor requirements
• Power requirements for control
system
• Diagnostics/control logic
• Technical descriptions
• Test requirements to include
instrumentation
• Product quantities
• Make or buy plan
• Launch pad environments
• Overall vehicle dimension
• Engine alignment tolerance
• Feedline drawings
• Vehicle aerodynamics
• Guidance and control instrumentation
locations
• Vehicle flex-body modes
• Propellant slosh modes
• Propellant feedline flex modes
• Qc_, 013and structural load constraints
• Mass properties control plan
• Documented control weights
• Weights, centers el gravity, moments
of inertia
• Mass versus time
• Thrust vector control (TVC) gimbal
capability (degree and rates)
• Kinematic analysis
• PU system definition
-.Inlet airflow constraints for ascent,
cruise, and landing
,',.,Air capture transition
• Sensor characteristics
• Computational characteristics
•Antenna types and locations
• Hazard analysis
• Fault tolerance requirements
• Failure mode effects analysis inputs
'.'CIL inputs
• Hardware design, development, testing,
evaluation, and production costs
• Cost trades
Key:
Control
46. The control
System
system
with specialists
from
process
the control
include
and the expected
mance
Gates.
Decision
gates for the control
synthesis
process
is accomplished
structures,
trajectory/G&N,
aerodynamics,
philosophy
environments.
of synthesized
software
Tools:
• General purpose simulations and control system
analysis packages such as Matlab and Marshall
Systems for Aerospace Simulation (MARSYAS)
• ELV,RLV, and RBCC
•. RLV and RBCC
-. RBCC only
4.3.5.2
figure
requirements
Output
for the avionics
for the G&N
group.
Before
gates
of acceptable
stability
margins,
ranges,
acceptable
reasonable
component
and
collaboration
with
passed
successfully,
the control
84
and approach,
Stability
designs.
errors
load indicator
2
other
which
requirements
analyses
group,
attitude
software
disciplines
architecture
and response
analyses
control
errors,
is the control
responses
set of outputs
sufficient
avionics,
allocated
of the process
a converged
system
by control
control
operability
and complexity
levels
as appropriate.
The control
design
and constraints.
and
on the control
are shown
propulsion.
Inputs
group
and others,
design
the perfor-
gates
until
plane by the control
and
and attitude
must
disturbances,
appropriate
is iterated
to the
component
the control
for these
in
in concert
and characteristics),
description,
for maximum
Threshold
in summary
specialists
are used to determine
for the loads
requirements.
is represented
process
(concepts
system
are made,
authority
design
systems
pass the
acceptable
to the system,
are
and
determined
in
the gates
can be
attributes
meeting
Reasonable
Component
and Software
Requirements
!
•Component and Software
Requirements
No
•Control Responses
_erodynarnics
• Attitude Errors
Stability
Acceptability
Margins
__
Stability
Analysis
No
Sufficient Control
Authority for
Maximum
Disturbances
Response Analysis
• Load Indicators
• Response Envelope
Control Philosophy/
Approach
Prescribed Concepts
and Characteristics,
Environments
Load Indicator
Acceptable
Range
I
Figure
Pogo
system
stability
and specifying
Therefore,
the Pogo
4.3.5.3
and design
lift-off
Dynamic
by performing
requirements
for Pogo
gate (not specifically
Separation
clearance
design
converges
Lift-off
to meet these
clearance
dynamic
clearance
parameter
uncertainties.
predominantly
system
stability
analyses
of the engine/feedline/tank/structural
suppressors
if needed
to achieve
Clearance
is adequate
Gates.
and extends
for tentative
extreme
system
gates,
on the figure)
separation
decision
gates
the separation
system
is obtained
through
This
analysis
must
Inadequate
clearance
margins
system
adequate
at acceptable
adequate
appropriately
require
iterating
margins.
pad
designs
analysis
system
or, for
(see
fig. 47).
with pertinent
vehicle
interface
variations
separation
reliability
specifications/drawings
determining
include
stability
margins.
and lift-off clearance
and parameter
include
requirements
stability
of the separation
of the launch
disturbances
adequate
Pogo
Separation
to the design
or modification
component
assurance
analysis.
the launch
gates.
design
are conducted
Appropriately,
Separation
separation
function
and Lift-off
system
design
shown
to specification
analyses
inputs.
into the analyses.
and reasonable
System
to control
potentially
and environmental
rated
is assured
is an adjunct
clearance,
46. Control
No
lift-off
extreme
must be incorpoclearance
and cost.
margins
When
the
can be finalized.
clearance
margins
disturbances
on the independent
by
and
variables,
pad interfaces.
85
R 7 ec0s,
e,,ao _jae
I
_
'
Component v_.
RequirementsI
!No
'! No
•Vehicle
Configuration
Separat,0nSystem
-I
Drawings/Specifications
l •w
I.MassProperties
• PropulsionCharacteristics
I-ControlSystem
_
•Environments
!_
I..............................
'._ v
|
v ,,..tj
Separation
..........
System
_ .............
_
_
AboveInputs
_
PlusPad
r_ _
Configuration/Interfaces_
',
_
Design
Liftoff
_
Clearance I
Assurance_
I
Adeauate
- _ •
Separat'°n
I
Dynamic
D::_amnl
e
_.[
I
Analysis
_
_
I
No
_
-
Clearance
=Margins
_
Adequate
Lir[on
Clearance
Margins
/_v_
_
No
ModifyLaunchPad/Interfaces
-_-..... ! .....................................................
..)
/
jJ
ModifyControlSystem _"
Figure
4.3.5.4
synthesis
Control
function,
the avionics
Tasks.
as distinct
47. Separation
In this report,
and propulsion
design
computers,
and software,
effectors;
i.e., actuators,
reaction
tling
or secondary
injection.
the control
a successful
design
design.
4.3.5.4.1
responsibility
between
requirements
to be part of
design
function
has responsi-
function
has responsibility
for differential
As will be noted,
a very
close
relationship
must
working
and these two hardware/software
activities
in design
Determination
plane,
consult
the control
system
design
the control
system
plane,
must be designed.
Avionics
and, therefore,
allocation
and propulsion
and propulsion
are the keepers
of the requirements
for control
system
that are allocated
by the system
plane fall in the former
category
(imposed
imposed
plane
is to deliver
load responses,
lift-off
by the control
design
As the design
iteration
among
are fed back
86
whereas
the requirement
Acceptable
and separation
control
system
configuration
and performance.
on the control
performance
means
design
acceptable
clearances,
etc. These
are requirements
function
and are quantified
by working
interactively
progresses,
if the control
the design functions
to the systems
plane
system
and disciplines
for trades
attributes
cannot
resolve
and possible
revision
down
function
Most
acceptable
design
do not meet the requirements
and
control
attitude
that must be given
the attributes
is
of the top-level
on the avionics
stability,
of the requirements
func-
for cost,
and, therefore,
with the other
the problem,
Control
the initial
are the design
requirements
for the vehicle.
is a joint
of the requirements
is the control
below.
planes.
and flowing
the keeper
planes),
etc. Control
be maintained
in order to achieve
Requirements
in identifying
for
throt-
in table 8 and are given
and the avionics
plane
functions
maintainability,
performance
power usage,
are summarized
and Allocation.
with the system
hardware/software
design
reliability,
propulsion
system
is assumed
that the avionics
and that the propulsion
to be the control
which
and valving
the system
to which
tions for the control
is taken
function
(RCS) thrusters,
function
planes
function
systems
1--Requirements
and avionics/propulsion
It is assumed
gates.
control
The main control
Task
design
hardware/software
functions.
control
and clearance
the control
from the control
bility for sensors,
between
system
errors,
definition
functions.
and informal
and sensitivities
allocation.
Table8.Primarytasksfor controlsystemdesignfunction.
Activities
1. Requirements
determination and
Interactions
System
Avionics
allocation
1. Consult with system to aid in initial requirements allocation.
2. Feed back attributes to system. Provide trade data
and consultation for revised allocation if required.
Trajectory
Guidance
2. Control authority
Tasks
Aerodynamics
Propulsion
Natural environment
Structural
configuration
Avionics
System
t. Determine wind, trajectory, and thrust disturbances with natural
environments and propulsion.
2. Consult with trajectory/guidance to determine acceptable
response excursions.
3. Consult with avionics/propulsion/structures to determine
reasonable control effector authority limits or trades.
4. For specified control concept and configuration, simulate with
appropriate disturbance inputs to determine response
excursions as functions of control authority.
5. If response excursions and/or control authority are not
acceptable, perform trades in concert with aerodynamics
and configuration to improve conditions. Alternatively, revisit
items 2 and 3 above.
6. If issues resolved among participants, send attribute
and configuration information to system.
7. If issues not resolved, take to system for top-level tradeoffs.
3. Detail control system
syntheses
System
Trajectory
Guidance
Structures
Propulsion
Aerodynamics
Avionics
1. Collect and derive requirements from system and interfacing
design functions, along with internal design criteria.
2. Perform iterative synthesis/analysis with increasing fidelity,
directed toward meeting requirements, constraints, and criteria
while balancing performance with cost and complexity
3. Work informally with other design functions to resolve conflicting
requirements. If resolution is not obtained, take to system
for top-level trades.
4. In addition to synthesized control system design, provide load
indicator responses, providing load relief design if required.
5. Interactively determine slosh baffle requirements.
6. Using clearance analysis, determine separation system
requirements and launch facility geometrical constraints.
Avionics
Structures
4. Component and software Trajectory/Guidance
System
requirements
11Maintain close working relationship with avionics to keep abreast
of hardware/software state of the art.
2. During control system syntheses, work with avionics in
specifying component and software requirements, to provide
acceptable performance, cost, complexity, reliability, operability,
and maintainability.
3. If performance cannot be achieved with hardware and software
that meet avionics attribute allocations, explore performance
requirement relief with structures (load indicators) and trajectory/
guidance (attitude errors).
Avionics
G&N
5. Verification
Propulsion
System
1. Develop high-fidelity analytical simulations.
2. Using simulation, verify system performance over full range
of parameter and environment variations.
3. Work with avionics to perform software v&v and verify
control performance in hardware/software test beds.
4. Verify separation and clearance margins using high-fidelity
response analysis, incorporating any available test-verified
component models.
5. Verify Pogo stability margins analytically, using test-anchored
dynamic models of propulsion system and structure.
6. Damping performance of the Pogo suppression system
may be confirmed by pulsing during hot firing tests,
with and without the suppressor.
87
4.3.5.4.2
Task 2--Control
sufficient
control
vehicle.
Effectors
tling,
authority.
Effectors
may be engine
etc. The range
the cycle
An important
are the devices
gimbal
(or existence)
since it can have
an important
Authority.
actuators,
of control
significant
activity
that cause
is sizing
force or torque
aerodynamic
capability
effects
early
in these
on the total design.
control
surfaces,
effectors
needs
the control
effectors
for
to be applied
to control
the
engine
differential
throtearly
in
the rate capability
of the effector
is
control
maximum
Also,
to be determined
variable.
Working
with natural
environments
and the propulsion
plane,
determines
wind,
trajectory,
and thrust disturbances
and their appropriate
statistical
combination
to provide a design disturbance set. Vehicle mass and aerodynamics
data are obtained from their respective
disciplines,
along with
uncertainties
definition
tions
in these
parameters.
(Note:
of parameter
uncertainties
is critical.)
to determine
maximum
hardware-responsible
surfaces,
response
personnel
problems
Control
excursions
from
aerodynamics/structures
Historically,
consults
acceptable
the propulsion
functions.
and,
reasonable
effector
design
functions
to obtain
values
to hardware
stages,
control
may
knowledge
of the above
A control
parameter
concert
architecture
to determine
excursions
and/or
response
with the aerodynamics,
and effector
are resolved
informally
among
to the system
plane.
or requirements
is the control
must be satisfactory
data
should
database,
ances
have
wind
their magnitude
will decrease
determination
reasonable
has
with
of aerodynamic
range
determination
of control
effector
to improve
described
attribute
adequately
parameters,
sufficient
uncertainties
tests, etc.) The simulation
a function
been
the above
historical
disturbances
authority
trades
the conditions.
above
and rate.
in
Alternatively,
may be revisited.
and configuration
and
are performed
If issues
information
plane for top-level
of the fidelity
converges
adequately
should
Margins
of the configuration
addressed
when
Control
based
is sent
tradeoffs,
produce
appropriate
System
For example,
a given
effector
response
to the fidelity
Synthesis.
aerodynamic
allow-
be provided,
and simulation.
The margins
design
cycle,
control
capabilities
excursions,
while
authority
which
are
considering,
of the models.
The core activity
of the control
requirements
while satisfying
in detail the process
used
specialists
to accomplish
and interactions.
considerations
(analytical,
including
a control system architecture
that best meets the vehicle
It is not the intent of this document
to describe
this, but to note primary
there
should
authority/rate
acceptable
cycle,
source
fidelity,
or headroom
definition
For
design
on the data
be of appropriate
in the system.
definition.
and margins
Task 3--Detailed
identified
to better
of cost and complexity
At each
and their uncertainties.
model
effects
addressed?
synthesize
constraints.
88
and rate
early design
on their
with
they are taken to the system
of inputs,
and this is key, uncertainties
4.3.5.4.3
also works
revision.
lags and unmodeled
in terms
planes
the control
definition
being
func-
(In very
based
are not acceptable,
definitions
are not resolved,
authority
as the design
as a function
and propulsion
authority/rate
realistically
tunnel
for response
design
authority
assessments
simulated
authority/rate
the participants,
If the issues
and
excursions
effector
structures,
excursions
When
is hypothesized
control
the response
reconfiguration,
Control
in the case
cost and complexity.
authority
area. Adequate
variables.)
system
variations
If response
control
in this
and guidance
function
of authority/rate
preliminary
with trajectory
to those
and the relationship
make
occurred
design
limits
personnel
have
plane
is to
interfacing
by control
In additionto thoserequirementsimposedby the systemplaneandthosederivedfrom interfacing
design functions and disciplines, control usesinformal designcriteria (for example,phaseand gain
margins)which havetheintentof assuringsatisfactorystabilityandresponse.
Input to theprocessincludes
the information notedin Task2 from otherdesignfunctionsand disciplines,plus detailedsensorand
actuatorcharacteristics,structuraldynamicmodes,sloshdynamics,andenginedynamics.The process
usesiterativesynthesis/analysis
with simulationsof increasingfidelity asthedesigncyclesprogress.
Typically, analysesand simulationsare doneon multiusedynamicsand control software(e.g.,
MARSYAS,Matlab,etc.)thataccommodates
avarietyof systemmodels.As thedesignprogresses
through
finer definition, the model of the vehicledynamicsis expandedto include higher frequencystructural
modesandsloshmodes.The model of the control systemcomponentdynamicsis expandedto include
higherordereffectsandnonlinearities.Thesemodelsareusedin stabilityandresponseanalysesto assess
theperformanceof the synthesizedcontrolsystemdesign.
Wind disturbancesmay berepresentedin very early designstagesby syntheticwind profilesthat
have
been
winds
are used
in Monte
Along
with
produces
relief
constructed
Carlo
satisfying
load indicator
if necessary.
analyses
Again,
or design
disturbance.
the system
response
internal
and external
requirements
and
to disturbances
it interactively
and dispersions,
determines
system
slosh
requirements
of the detailed
design
and launch
is determined
data and its uncertainties
4.3.5.4.4
Task 4--Component
and Software
avionics
set of requirements
and propulsion
relationship
planes.
with hardware
art and capability.
During
component
to specify
represent
acceptable
is captured
Before
and software
planes
for control
control
and during
specialists
cost, complexity,
reliability,
in the system plane allocation
If performance
cannot
the design
control
requirements
be achieved
facility
and
geometrical
of requirements
One of the main
process,
software
control
and propulsion
assessment.
outputs
of the control
that is provided
specialists
maintain
to keep abreast
hardware
to the
a close
of the state of the
performance
with component
clearance
and adequate
with the avionics
to the avionics
load
to critical
works very closely
and maintainability.
design
constraints.
have been subjected
and
through
that both meet system
operability,
of requirements
system
to provide
components
in avionics
system synthesis,
and software
the control
the system
requirements
Requirements.
sense.
criteria,
by satisfaction
the input and simulation
sets of measured
in a probabilistic
configuring
baffle
where
is a converged
Subsequently,
to determine
separation
adequacy
a high wind
analyses
responses
Also,
determines
margins,
plane
to represent
and propulsion
requirements
and
The latter set of requirements
and propulsion
planes.
and software
that meets
the avionics
and propulsion
plane allocations,
control explores performance
requirement
relief with the structures
plane
(load indicators)
and the trajectory/guidance
plane (attitude errors). If resolution
is not obtained, the issue
is taken
to the system
The
system
plane for top-level
process
is complete
performance
requirements
maintainability
allowances
requirements
for uncertainties
when
trades
or requirements
the component
(imposed
allocated
and margins
and software
on the control
to the
revision.
avionics
plane)
and
requirements
satisfy
and the cost, reliability,
propulsion
planes.
both the control
operability,
Again,
and
appropriate
must be included.
89
4.3.5.4.5 Task5--Verification. Verificationof the controlsystemis accomplishedprimarily with
simulationsof two types:(1)Analytical simulationsand(2) testbeds.High-fidelity analyticalsimulations
aregeneratedto modelthe control systemandthevehicle/environmentin ascompletedetail aspractical.
The combinedsimulation is run using the full range of expectedparametervariations to ensurethat
satisfactoryperformanceis attainedat all operatingconditionsandsystemvariations.Avionics testbeds
useflight-typehardwareandsoftwarewith simulatedvehicleaspectsto confirmthecorrectfunctioningof
the controlsystemasimplementedphysically,asdiscussedin the avionicssection.
Verificationof lift-off andseparationclearanceis done
only be done analytically,
it is important
also is done
using
during
damping
by analysis,
engine
effect
hot-fire
9O
tests can be used
of adding
by the best-available
that sufficient
test-anchored
Pogo
analytical
to obtain
suppression
models
dynamic
margins
are maintained.
models
of the engine
engine
systems.
in analytical
dynamic
Sloshing
response
simulations.
Pogo
until flight.
stability
and structure.
information
and flexible-body
but are not fully validated
Since
this can
verification
Pogo
pulsing
and to show
stabilization
the
are verified
STRUCTURES
System
Aerodynamics
Trajectory/G&N
,,,
Control
Structures
Thermal
Propulsion
Avionics
Materials
"°i
Manufacturing
Other
Figure
4.3.6
Structures
48.
Design
Design
The
connection
in figure
48.
and the other
design
functions.
key
decision
all the
above
The
e.g.,
system
tanks,
between
The
gates
are delineated
structures
interstages,
technical
integration--structure
design
function.
Function
is delineated
structural
process
process
technical
illustration
the design
depicts
the
In addition,
it shows
the work/information
that
are required
in this
design
thrust
integration
relationship
to develop
and
and the structures
between
assess
the
flow
the
structures
process
structures
that
attributes.
design
function
design
function
is supported
The
details
by
of
section.
function
frames,
is defined
lines,
as any
ducts,
design
components,
activity
etc.,
involving
and
finally
structural
the
subsystems;
total
structural
(vehicle).
91
4.3.6.1
flow
among
Structures
discipline
Design
functions
plane is the structures'
design
the initial configuration,
then establishes
interact
Plane.
The structures
to accomplish
and its various
attributes.
moves
through the definition
the parameters
and their uncertainties.
with the structural
analysis
and thermal disciplines.
and materials.
Function
required
etc. All these discipline
analysis
functions
system
The flow diagram
starts
of philosophies,
tasks are compatible
discipline
culminate
functions
design.
The output
of this
with the requirements
criteria, procedures,
The next blocks
are the discipline
to provide the structural design data. Included
Inputs to the discipline
The structural
plane in figure 49 shows the information
the structures
and
and approaches,
functions
which
are the trajectory, controls,
data inputs from natural environments
are loads and response,
in the structural design
discipline
stress, stability,
which
buckling,
produces the structural
design. The discipline
functions in conjunction
with the design function are fundamental
in defining the
structural
attributes. The integration of the tasks is performed using inputs and outputs from one discipline
to the other, as discussed
results
which
In cases
in the following
sections.
must be passed through a prescribed
where
gates cannot be met,
The tasks performed
on the structures
set of gates that determines
the structures
plane communicates
plane produce
when the design is completed.
with the system
plane to balance
out the design.
Informal_
_!ntegrationl_
Structural
I
Requirements
]-_
and Constraints I
I Configuration
Definition
Philosophies
H
I
Yes_
No
(Stop)- y
(Iterate)
[._
Criteria
Structural
Proceduresl I
Approa_:hes
I
Parameter Matrix
[I
I
Structural
and
Un#ertainti_$
Shaping,
H
Performance,
Trajectory
ond Guidance
....
Structural Attributes
• Assurance
i
Structural
Design
- Strength
- Endurance
Stress
- Stability
- Reliability
• Weight
• Cost Factors
Thermal
i
i
i,
,,
I'|
i,
and
Loads
Response
• Complexity Factors
• Failure Modes
• TRL Assessment
Controls
"_
Special
Stability,
Analyses
Buckling
and Tests:
Figure
As discussed
outputs
inputs
and outputs
sis outputs
tural
previously,
(see ref. 2 and
analysis
an NxN
app. A). Table
for structural
are shown
outputs
49. Structure
analysis.
diagram
9 depicts
Shown
horizontally,
and structural
are flex-body
modes,
and q-beta
constraints
as input to control,
slosh
damping
requirements,
q-alpha
92
and autopilot
definition.
and
function
plane.
has been developed
consisting
an exploded
scale
are the inputs
from thermal
analysis
propellant
q-alpha
constraints,
design
while
inputs
slosh
are shown
modes,
control
q-beta
portion
of a matrix
of inputs
and
of this diagram,
showing
the
and control.
vertically.
propellant
Structural
analy-
For example,
struc-
feedline
flex modes,
provides
to structural
analysis
the inputs
envelopes,
flex-body
mode
frequency
and
of
Table
9. Example
expansion
of vehicle
design
3.5
Structural analysis
• Temperaturegradient
design limits
• Structural
Temperatures/gradients
3.6
Thermal
NxN
diagram.
• Vehicle flex-body modes
• Propellant slosh modes
• Propellant feedline flex
modes
• Q'Alpha, Q'Beta and
structural constraints
• Slosh damping requirements
• Qxalpha versus qxBeta
envelopes
• Flex-body mode
frequency constraints
• Autopilot definition
• Vehicletransient response
to wind disturbances
4.3.6.2
integration
Structures
affect
and
outputs
are drawings
design.
For
endurance
Gate
involvement
basic
structural
interpret.
(fatigue
metrics
of the
NxN
that
system
while
detail
the
activities
gives
the
requirements
well
as the
two-way
and the flow.
loads
The
output
loads
products
of structural
including
vehicle
structural
result
related
plane
structures
including
and
outputs.
are
separate
shown
are
Also
shown
Figure
51 depicts
section
to combining
which
on
the
cost,
etc.
right
side
the
gates
are clear
which
and
for
and left
to the
the
and
outputs
of the chart
shows
the
structural
from
vibroacoustics
for the life
of the
chart.
Other
reader
to
or an
design
into
with
process.
The
left
are
defined
as
analysis
and dynamic
or durability
internal
stability,
augments
analysis
inputs
the input
and
gates
metrics
structural
the NxN
the structural
the
concepts
criteria
meets
As a result,
shows
corresponding
One-way
outputs
is then
meet
analysis
figure
prescribed
are the
change
of both.
criteria.
50. This
the
must
structural
is an integration
analysis
options,
inputs
other
etc.
The middle
is central
to the stress
The
requirements,
discipline
in figure
assurance
design
plane.
the
shown
in either
write-up
structures
analysis
The
and reliability.
be met
and
configuration,
design.
and fracture),
analysis
is input
are
cannot
of the
inputs
gates
and specifications.
example,
to rebalance
the
side
structural
plane
diagram
activities
more
The
decision
assessment
the
The
Structural
The
strength,
separate
3.7
Guidanceand control
of structural
characteristics.
that
Gates.
2
flows
tasks
analysis.
analysis.
are
The
shown
93
Yes
TPS
_.
Accommodations
/
Propulsion
_
Accommodations
J
Operability
I
"'"_//
• Accessibility
Inspectibility
I
I
/
i
-_
"
_ctural
Drawings
and
Specifications
Desig n
I
'_"
Assurance
Structural
• Processing
and Checkout I
• Stability
•Structural
Strength
• Endurance
_Yes
• Reliability
I NO_
Assessment
• Maintainabilityl..._
|
Launch Facility
Manufacturing
yNoI coom o°at'on J
Concepts
and
Prescribed
Characteristics
No :
Y
""V
",,,..................
Yes
Assembly
Figure
50. Structure
design
r-
I
function
....
Mequlremeras
• Program Ground Rules
I" Factors of Safety Criteria
_
_
_
I" Fracture Control Requirements W
• Constraints
I cost
I
I Consultation Options Trades Analysis
'
'
'
'
_
_
I IVibroacoustic Analysis
I I" Random Vibration and Shoc4
I I Criteria
I" Component Accelerations
I
_
•Onlnpu
ne'Wav)p
mutS(On
[
.
Y)
• Communication
and Data
_ceiWnaYlnd
Data
,
L
i.VehicleLineLoads
I . or
FEM Loads
. ..
uomponen,
_cce,era,,ons
I[i
I|
u Power
•• El_'Ctr;c_l
m
Two Wa
Inputs/Outp uts (y)
[
l
IB
U
I , Load Spectra
........
I * ueslgn uonolllons
I
-Ground
Handling
..................
_
I
and .Structural
Destgn
_iO!ii_iiioVehtcle
Cont=guratmn
•
,
.
•
ries
• Aerodynamics and Induced
_
Environments
_
• Thermal
_
• Mat?rials
....
and Controls
Controls
••Gutdance
G.uidance and
• Propulsion
• Ground Operations
• Safety
• Reliability
_
_
W
_
_
_
I
I
94
IStress Analysis
_1
. .
• Structural
Stress Anatysis
Sizing
El
..................
_, _1.
p
_1"
-- SUI.........................
Id_
Ilall_pUI v t t{IHUII
a_dUlH_;>b
FIHH_
L_UHI_tl
....
in
_[•
-_Cee_ _ Laa_di_,,
_l
- R over'
_
Ii
- ec
ry
............ _
Stresses
and
Stratus
Margms
of
Safety
,
.
Deflecbons
• Strength Verification
I Test Requirements
_
.....
Structural Dynamic Analysis bl
, Transient Analysis
ll
o Structural Models and Modalll
Analyses
B
• Propellant Slosh Dynamics i
Life Anai_;sis"
Fracture and Fahg ue
Analysis
Cycles and Time to Failure
Proof Factors
Critical Initial Flaw Sizes
• Flutter Assessment
• Pre-Test and Post-Test
Analyses for Modal Survey
51. WBS
'
t I (High Frequency. >50Hi)
_ I ...........
_................................
I
..........
"
I_
Lo_du_._,y.,_
.
I
uestgn LOaO
B
Inputs (One-Way)
• Mass Properties
_e
rrtoenSents
-
r
_
gates.
Internal Flow
I
Figure
• Weight
Performance
• Deflection
•
2.4--structures
analysis
_
B
If
Products
Random Vibration
and Shock Criteria
Design Loads
Structural Dynamic
Analysis
Modal Survey Tests
Analysis
Strength Verification
Test Requirements
Stress Analysis
Fracture and Fatigue
Nondestructive Test
Inspection Requirements
design
process
flow diagram.
2
The structuraldesignflow chart,figure52, showsthe structuraldesignactivity andhasthe same
format asthe structuralanalysisflow chart.Structuraldesigndealswith componentgeometry,interfaces,
subsystemlayout,etc.The majorproductsarethedesignspecificationsandthe drawings.
Requirements
Program/Project
• Concepts
• Design
• Verification
_
I
L
r
_
I
I
I
I
Internal Flow
Vehicle Configuration
• Subsystems
Interfaces
ruts (0ne-Way)
• Natural Environments
Products
• Vehicle Configuration
• System Layout
• Construction Type
• Detailed Drawings
• Structural Mass
Moldline
Structural Element Function
.
Ioputs/Outp,,ts (Two-Way)
• Performance and Trajectories
• Materials
• Manufacturing
• Guidance and Controls
I
Structural Design
• Component Geometry
Construction Type
- Dimensions and Tolerances
Mass and CG
CrossSection Properties
• Interfaces
Mechanical
Datums
• Subsystem Layout
-Subsystem Placement
Line Routing
Access Panels
Vent Ductwork
• Holddown/Release Mechanism
• Mass Properties
• Thermal
• Structural Analysis
• Propulsion
• Aerodynamics and Induced
Environments
• Communication and Data
Handling
• Electrical Power
• Ground Operations
• Flight Operations
• Safety
• Reliability
• Cost
• Subsystem Layout
• Structural System
Description
• Functional Requirements
• Vehicle/Pad Interface
• Transportation
Requirements
• Verification Requirements
- Staging
Active Systems
Passive Systems
Hazards Benefits Reliability
OperabilityI Maintainability
Cost/Makeor ResourcesRequiremenisTest
S/W
Server
Buy
Utilization
]RequirementsAlgorithms Needs
Materials/ Technical Sizing/
Conceptual
PartsList
DescriptionsConfiguration
Sketches/Layouts
Figure
on the
structural
details
52. WBS
2.1--vehicle
configuration
The N×N diagram
is a complement
structures
The
analysis,
given
plane.
structures
and the system
in section
4.3.6.3
plane.
which
and structural
to the structures
plane
diagram
The tasks
plane,
shows
provided
design
process
providing
the
linkage
in reference
flow diagram.
more details
between
2
of tasks
structural
2 can be correlated
shown
design,
to the task
follows.
95
Reference2 delineatestheWBS taskswith inputsandoutputsasshownin tables10andl 1.
Table10.WBS 2.4--structuralanalysistaskdescription.2
Inputs
• Projected groundrules and goals
•Factors of safety criteria and fracture
control requirements
•Launch platform finite element model
•Ground and ascent wind models
•Vehicle geometry
•Vehicle/pad interface geometry
•Holddown/release mechanism definition
•Structural details
Tasks
3.5.1
Vibroacoustic analysis
3.5.2
Load analysis
3.5.3
Structural dynamic analysis
3,5.4
Stress analysis
3.5.5
Life analysis
•Component installations
•Shock sources
•External aerodynamic pressure
distributions
•Compartment pressures
•Protuberance airloads
•Acoustic/overpressu re definition
•Fluid dynamic loads (buffeting)
•Structural temperature and gradients
•Slosh damping requirements
•Q-alpha, q-beta envelopes
• Flex-body mode frequency constraints
•Autopilot definition
•Vehicle transient response to wind
disturbances
•Weights, centers of gravity, moments
of inertia
• Ignition and shutdown thrust transients,
timing
•Steady state thrust oscillation
•Ullage pressure and tank fill heights
versus flight time
•..,RBCC exhaust/thrust
•.,-Forebody inlet
•Material properties
•Material allowables
•-,,Materialselection consultation
,-.,TPS design definitions
•Material thermal (required/expected)
•Drawings for flight GSE
• Launch sequence timelines
•Vehicle integrated OPS concept and
requirements
• FMR and LMR
• Hazardanalysis
• Faulttolerance requirements
• System and component reliability
allocation and estimation
• Failure mode effects analysis inputs
•,.,CIL inputs
Key:
• ELV,RLV,and RBCC
,,,,RLV and RBCC
,.,- RBCConly
96
Tools:
• Commercial soffware---NASTRAN, ABAQUS,ANSYS,
PATRAN
• In-house software--dynamic loads analysis programs,
NASGRO,bolt strength analysis software
• In-house vibration data base
Outputs
•Structural sizing, margins of safety
•Loads and deflections
•Propellant slosh baffle sizing
•Q-alpha, q-beta constraints and structural load
indicators
•Temperature gradient design limits
•Vehicle flex-body modes
•Propellant slosh modes
•Propellant feedline flex modes
•Q-alpha, q-beta and structural load constraints
•Structural analysis of lines and brackets
•Establish dynamic envelop of feedline
•,.,-Aft/forebody structures
,., Life limit
oVibroacoustical design criteria
• Review of battery cell design (pressure vessel)
•Structural failure modes
• Failurepropagation logic development
•Test requirements to include instrumentation
Table
11. WBS
2.1--vehicle
configuration
lnpuls
• Projected groundrules and goals
• Production and ground OPS
• Critical interfaces
• Subsystems definitions
• EPAand OSHA constraints
• Environmental 0PS constraints
•Preliminary design concept and
data bases
•Staging requirements
•Propellant requirements
•- Entry propellant weight
• Pressure vent sizes and locations
•Structural sizing and margins of safety
•Loads and deflections
• Propellant slosh baffle sizing
•Cryogenic insulation sizing
•Active thermal control system sizing
•Temperature and propellant sensor
locations
• Maximum engine deflection
• Control sensor locations
and structural
desig-n task description.
Tasks
3.1.1
Configure vehicle
3.1.2
Layout 3D structural model
3.1.3
Determine suitable construction type (e.g.,
truss, isogrfd, etc.)
3.1.4
3.1.5
Select appropriate material
Calculate structural member sizes
3.1.6
Analyze crosssection moments of inertia
3.1.7
Determine structural component mass and CG
location
3.1.8
Assess provisions for clearanceand access
3.1.9
Locate subsystems
3.1.10 Route subsystem lines
3.1.11 Produce detail drawing for manufacturing shop
3.1.12 Design structural components
3.1.13 Identify shock sources
3.1.14 Specify critical dimensions
3.1.15
Establish suitable manufacturing tolerances
• Control surface deflection requirements
• Mass properties data--weight;
e.g., inertias
• Propellant inventory
•Propulsion system layout
•Tankinternal pressures
•,.,Forebody moldline (iterate required
air volume)
•,--Staging requirements
•-,,Propellantrequirements
•Material allowables
•,-,Material selection consultation
•,-TPS design, thermal materials
required
• Packagingvolumes required
• Electrical power system (EPS)
component details
•Access requirements
•,,-Turnaround, launch, and landing
facilities
•Vehicle integrated OPS concept and
requirements
• On-orbit flight OPS
•- Landing gear drawings
•Fabrication parameters
•Range safety requirements
• Hazardanalysis
• Fault tolerance requirements
•Reliability estimates
•Failure mode effects analysis inputs
•-, CIL inputs
•System-to-subsystem reliability, allocations
Hardware design, development, testing,
evaluation, and production costs
•Cost trades
Key:
2
Outputs
• Engine alignment tolerances
• Vehicle geometry and structural details
• Feedline drawings
• Component weight estimates
• Parts list
•Cross-sectional properties
• Line routing zones
• Pressurant bottle locations
,,,-Preliminary air column
,,,,-Profile
• Power return thru structure
•Component installation
•Verification requirements
•Transportation requirements
•System definition and design
description document
•Holddown release mechanism
,,Hazardanalysis inputs
,Schematics
• Failure mode effects analysis inputs
,,--ClL inputs
•Technical descriptions
• Test requirements to include
instrumentation
• Production quantities
• Make or buy plan inputs
Tools:
• Commercial software--CAD platform and translators,
EMS
• In-house software--optimization design codes
• ELV,RLV,and RBCC
,- RLVand RBCC
•,, RBCConly
97
Table
Activities
1. Requirements
determination and
allocation
12. Primary
Mass properties
System
Control
Trajectories
Materials
Trajectory
Control
Aerodynamics
Materials
Thermal
Propulsion
Avionics
Propulsion
3. Structural
capability
determination
Loads
Thermal
Materials
Aerodynamics
4. Structural design
for structures
Interactions
Propulsion
Aerodynamics
2. Loads analysis
tasks
Loads
Thermal
Materials
Stress
design
function.
Tasks
1. Consult with system to obtain operations philosophy,
constraints, cost, mass fraction, etc.
2. Obtain initial configuration definition.
3. Provide to systems the discipline peculiar criteria for formal/legal
application.
4. Develop discipline specific verification requirements.
5. Setup allocated requirements, discipline specific criteria, etc., into
the metrics for decision gates.
6. Flow up derived requirements to system.
1. Setup describing equations (models) of the system (separate sets
are required for the various mission events such as transportation,
liftoff, max "g," max "q," separation, etc.).
2. Develop all input data, configurations, environment, etc., and
execute loads analysis.
3. Work with trajectory, control, etc., to resolve excessive load
conditions. Resolve informally, if possible.
4. Consult system to resolve remaining loads issues, constructing
derived requirements such as load relief controls.
5. Input loads to stress and design.
6. Work with propulsion, aerodynamics, and avionics to
accommodate packaging and special requirements in the
design. Continue to work trades and balancing activities.
7. Insure that cost, reliability, and operations are a part of the
design trades and metrics.
1. Determine strength margins, fatigue margins, fracture control
requirements, and structural stability margins.
2. Coordinate with design and loads to informally resolve
undesirable margins.
3. Consult systems for trades and requirements changes to resolve
remaining margin issues.
4. Continue to work with design to resolve issues and concerns
through design changes.
1. Using system requirements, loads, thermal, and stress perform
detail design, outputting configurations (geometry), materials,
specifications, drawings, etc., to serve as baseline of next iteration
Continue to work with stress, thermal, and systems to upgrade
design to accommodate requirements change, reduced margins,
and issues. Provide trade date and recommendations to
.
program on issues.
5. Verification
98
!Testing
Loads
Thermal
Stress
Work with stress, loads, and thermal to determine test facility
requirements, test condition, instrumentation, and data system
requirements.
2. Work between disciplines to evaluate results.
3. Flowup anomalies to system for design changes or changes in
operational constraints and procedures.
4. Final structural validation achieved in development flight tests.
1,
Structural
integrated
analysis
structural
4.3.6.3
Tasks.
determination,
The top-level
tasks
(1) Requirements
are shown
design,
with the corresponding
tasks.
4.3.6.3.1
plane
Task
and
separately,
structures
them,
whereas
plane
are shown
these
Determination
and Allocation.
The
them
system
goal
to the planes.
in table
(2) loads analysis,
For each
plane.
and allocate
plane
and allocation,
and (5) verification.
l--Requirements
the structures
compartmentalize
of the structures
determination
(4) structural
system
design
activities
are
herein.
into five categories:
along
and
is to take
category
the
Task
12. They
are divided
(3) structural
capability
interactions
are
1 is a joint
the total
In this case, typical
system
shown
task between
level
the
requirements,
requirements
allocated
to the
to properly
accomplish
this
are:
• Weight
• Geometry
• Cost
constraints
• Operations
• Schedule.
constraints
The structures
allocation
task.
design
function
works
The
groups
develop
a second
set of requirements
and controlled
or managed
approved
there
and levied
is a detailed
ments.
and
discipline
Generally,
the criteria
the project.
criteria
by the project
set of these criteria,
for loads
analysis,
vibroacoustics,
Included
in these criteria
test, qualification
not only
meeting
accuracy,
etc. If the model
must be verified.
Finally,
during
are strength
the accuracy
the design
requirements,
determine
the structures
these
design
specifications
application
Examples
wind
biasing,
The
total
design
process,
of derived
requirements.
and formal
variation
documents
launch
derived
discipline
criteria)
is acceptable
and complete.
becomes
the gate
to the system
and other design
and attributes
in constraints
for the other
result
with the structures
Therefore,
function
planes
case
(allocated
acceptance
Gates
data
all models
will evolve
etc. in each
The specifications
such as static
of models,
are requirements
requirements
fracture,
and traceability.
requirements
constraints,
set of structures
require-
the system,
and
requirements
ranges,
are
in structures
as fatigue
but validation
requirements
plane are provided
and interaction
such
These
use as legal
by the disciplines,
criteria
of the input data is immaterial.
day-of-launch
if the structural
parameter
criteria.
Typically
for general
but also verification
in the criteria
and development
slosh
the new
factors
criteria,
is wrong,
control,
baffles,
be tailored
methods.
given
part of the legal requirements.
accommodate
and must
and attachment
and acceptance
that are technical
by the disciplines.
endurance
requirements
function
by NASA
criteria,
are not only safety
become
design
officially
are too comprehensive
examples
include
derived
documented
Typical
and dynamic
with the system
and
can
for load relief
the design
must
requirements,
criteria
(metrics)
that
and design
attributes
from
planes.
Obviously,
some of
that place
limitations
on their
design.
99
4.3.6.3.2 Task2--Loads Analysis.Utilizing inputsfrom (1) configuration,(2) naturalenvironment, (3) aerodynamics,(4) materials,(5) thermal, (6) trajectory,(7) control, and (8) propulsion; the
externalload environmentsaredetermined.For efficiency andease,the loadsanalysesare performed
separatelyfor thevariousmissioneventsinvolving (1) transportationandhandling,(2) lift-off, (3) max q,
(4) max g, (5) separationandstaging,(6) docking,(7) reentry,and(8) landing andrecovery.Theseinputs
arealsoaddressed
in the NxN diagram,processflow, andWBS charts.Tables10and 11definetheWBS
taskswith inputs andoutputs (products)which include the load analysis.Table 12 defines the total
structuralanalysistasks,includinginputsandoutputs,with the loadanalysisbeingoneelement.The tasks
in thesethree tablesare compatible.The other designactivities are coveredin the subsequenttasks.
Structuralmodels,both rigid body anddynamic,mustbe developedfor eachevent,describingthe plant
characteristics.
Thesemodelsarethencombinedinto appropriatesystemmodelswith all theenvironmental
inputs,constraints,etc.,anda responseanalysisis run to determinethe combinedloads.Thesemustbe
definedin somestatisticalor quantifiablemanneraccountingfor variationsandunknowns.Theseresults
alongwith otherdatabecomethe inputto thenext task.
During this process,if excessiveloadsexist,thenthe load specialistworks informally with other
disciplinesin an attemptto resolvethe issue.Can aerodynamicsbe altered?Are the variationsof key
parameterstoo conservative?
Are the criteria too conservative?Can the wind model be changed?Are
dynamictuningscreatinga problem,requiringdetuning?
Occasionally,theissuescannotberesolvedinformally.In thiscasethe issueis carriedtothesystem
plane where tradesand balancesare accomplishedacrossthe subsystems,designfunctions, etc. For
example,theconfigurationshapemay bealteredto changetheaerodynamics.
In orderto reduceloads,yet
maintainanacceptablesystem,criteriacanbechangedaswell asdesignlevelsof parameteruncertainties
andtheir combinations.
Achievingthe acceptableloadssetrequiresthat the loadsspecialistsnot only communicateand
understandin depththeir specialty,but that they havean understandingof the interactingdisciplines.
Togetherthey mustclearlydefinerequirementsfor the neededinputdata.For example,theymustspecify
the neededresolutionof theaerodynamiccoefficientmatrix, pressuredistributionspatialresolution,and
critical locationsrequiring higher fidelity resolution.The interactionswith other disciplines are very
importantandcomplex.They includebut arenot limited to the following:
• Trajectories---definitionsof theflight pathandangles
• Control--the controllogic, controlgains,andthedynamicresponses
• Interfaces----definition
of mechanism
envelopes,
constraints
requiredfor separation,
docking,etc.
• Material--materialspropertiesdefinition asa functionof operationalenvironments
• Aerodynamics---definition
of the aerodynamic
and acoustic environments.
The detail
documentation
the metrics
of the load process,
(see bibliography)
for deciding
factors
are normally
validation
pertains
100
technically
adequately
covers
when the job is finished
used
on loads
until
also to both the stiffness
and computationally,
those
details.
What
and how the models,
the model/data
and mass
is not a part of this report.
is key here is an understanding
data, etc., are validated.
verification/validation
distribution
Other
of the models.
of
Uncertainty
are accomplished.
This
4.3.6.3.3 Task3--Structural Capability Determination.This taskis concernedwith determining
the structuralcapability using the loads and other inducedenvironmentalinputs suchas thermal.The
capabilityassessments
includeatleastthe following:
• Strength
• Ductility
• Fracture
• Fatigue
• Stability
• Deflection/interference
• Attachmentcapability(welds,fasteners,bonds,etc.)
• Vibroacousticcapability.
Very specific formal criteria are levied for eachof theseareasand must be met or a waiver
approved.Thesecriteria in generalarethe meansof defining marginsfor the variouspredictedfailure
modes.If they are not met, then the sameprocess,informal and formal, as discussedunder loads is
employed.Therearefour maininteractions/interfaces
for the stressfunctions:loads,thermal,materials,
andfacilities.Theloadsandthermaldisciplinesdefinetheenvironmentsincludingaccelerations,
deltaP's,
etc. The materialsdiscipline definesthe materialspropertiesasa function of operationalenvironments.
Assemblyandlaunchfacilities defineinterfaces,constraints,etc.
The activities on the structuresplanerequireunderstandingload pathsand stressvariationsand
concentrations.As a resultnot only mustthe specialistunderstandthe manyvariouscomputerizedtools
suchasfinite elementcodes,thermalcodes,grid codes,graphiccodes,etc.,but mustbeableto analyzeby
handspecialcasesof structuralresponseandevaluatethem with respectto criteriaandspecifications.
The structuralanalysisfunctionandthestructuraldesignfunctionarehighlyinteractive.Thereare,in
general,two avenuesopenif thecriteriaarenotmet:(1) Changethedesigntoaccommodate
theenvironments
or (2)reducetheenvironments
(loads)asdiscussedunderloads.As aresult,communications
betweenloads,
design,and stressaretightly knitted.Many problemscan be solvedinformally amongthe threegroups;
however,somecritical tradesmustbe madethroughthe systemsplanedueto the high complexityof the
interactionswhich requiretestsandcompromises.
4.3.6.3.4 Task4--Structural Design.Structuraldesignis oneof the mostcomplextasksin developinga launchvehicle.It requiresstronginteractionswith all otherdisciplines,subsystems,
etc.,andthe
designermustbe the structuraldesignintegrator.This dictatesthat the designerhasnot only an indepth
understandingof design(load paths,functions,materials,attachments,etc.)but alsoanunderstandingof
thesupportingdisciplines,subsystems,
elements,etc.Partsstandardization
knowledge,aswell asaccepted
designapproaches,is alsoimportant.Materials selectionis a key choicein design.All the marginsare
drivenby materialsselection,asis massfraction,weight,etc.The structuraldesigntasksaresuboptimized
tasksin thatthedesignis drivenby constraintsandinterfacerequirementsaswell asloadsandthermaland
manyother tasks.As eachdesigncycleis approached,the previousdesigncycleconfigurationis refined.
In eachnew cycle, all problemsraisedin the previouscycle are accommodated
or challengedon the
systemsplaneagainstotherrequirements,criteria, anddisciplines.In generalthe final decisionmustbe
approvedat the systemlevel.
101
design
Not only must
the design
considerations
of the following
tasks accommodate
other
loads and thermal,
but, also, they must accommodate
factors:
• Cost
• Performance--mainly
weight;
• Operations--processing,
check
• Propulsion--thrust
frames
• Pyrotechnics--location
• Launch
location,
components,
design
process
is further
particularly
shapes
etc.; and manufacturing
choice
of attachment
and weights.
The design
is complete
structural
as shown
etc. The structural
are satisfied.
All subsystems
accommodated
efficiently.
and operations.
When
4.3.6.3.5
vehicle
all these
integrity.
is the preferred
structural
approach;
analysis,
analysis
viable
option
than limit.
slightly
greater
margins.
The philosophy
expected
flight
testing,
102
The
model
and analysis.
missing
margins."
of structural
testing
in lieu of testing.
to flight
hardware
the analytical
Structural
verification
weight,
margins
facility
must be
assembly,
can be finalized.
of assuring
meet or exceed
are adequate
and testing.
and
Protoflight
but validates
the maturing
testing
of
of structures
is
a combination
to loads
failure
above
to that load, update
testing
fidelity
the structure
margin
the
to ensure
Structural
of critical
to a specific
is, therefore,
design
cost,
manufacturing,
and understanding
model
on
the top-level
is one of the key tasks
similarity,
a major
and structural
and launch
of acceptable
is "Test the hardware
correlate
significant
constraints/procedure
link is quantification
testing
5 percent),
to predict
cases
risk
other
first that the structures
of analysis,
to the cost
a small
of protoflight
load (usually
that the operational
is a combination
incurs
and
criteria
ring
impacts
include
are met with appropriate
systems
ensures
is also
All have
gates
avionics,
to
etc. The wide
etc.,
process.
and specifications
of structural
such as orthogrid,
Those
when all the stability
process
composites
metallurgy,
bolts,
accommodations,
requirements
Verification
due
powder
are satisfied.
must meet the gates
is used in special
which
gates
gates are met, the drawings
however,
from
the design
such as TPS, propulsion,
the design
and, second,
of materials
adhesives,
complicate
is achieved
to fly. The verification
another
use the updated
assurance
The verification
etc.
techniques
casting,
rivets,
greatly
subsystems
Task 5--Verification.
is ready
as welding,
50. The top-level
Finally,
for components,
choice
stabilization
such as welding,
and interfaces
requirements/specifications
structural
of tanks and fairings;
assurance,
mass fraction,
a launch
by the wide
when all the decision
in figure
and support
required.
complicated
such
and optimize
for the TPS
location
cost considerations
margins
requirements,
provides
approaches
approaches
Additionally,
considerations
etc.
and actuator
etc.
the support
characteristics
stringer,
structural
provides
• Materials--material
consideration.
engines,
sensors,
to accommodate
accessibility,
design
shapes,
lines, ducts,
and security
facilities--interfaces,
design
accessibility
of electrical
• Packaging--structural
The
metallics;
out, accommodation,
and assembly---design
• TPS--structural
efficiency
and element
• Avionics--accommodation
• Manufacturing
structural
mode
the largest
the model,
then
of similarity;
a. Similarity.
Verification by similarity is valid where a similar structurehasbeenverified by test and the
similaritiescanbequantified.In general,this techniqueis usedwhentwo or moreof thesamearticlesare
built. In the caseof componentswhich must passenvironmentaltesting at both the qualification]
verification level andacceptancelevel,only onearticleof a family (i.e.,commonvalves)is qualification
tested,thus qualifying the othersby similarity. Acceptancetests,however,mustbe performedon all
articles.Theseenvironmentaltestsinclude acoustic,vibration, and thermal.Sinceit is expensiveand
schedulecritical, vibrationenvironments(criteriathat areacousticallydriven)cannotalwaysbeverified
by acoustictests.Two techniquesare usedto verify thesecriteria: (1) Data bank scaling of similar
structuresthathavebeentestedand(2) statisticalenergyanalysis(SEA).
b. Testing.
As statedpreviously,testingis the preferredmethodof verifying
schedule
system
many
times
levels.
prevents
Structural
• Component
testing.
testing
qualification
Structural
has several
testing
occurs
major
categories:
and acceptance
(vibration,
the structure;
at the part, component,
acoustics,
however,
cost and
subsystem,
and
thermal/vacuum)
• Dynamics
• Strength
• Stability
• Aeroelasticity
(flutter,
divergence,
is accomplished
to meet
etc.)
• Fatigue
• Proof (fracture)
• External
loads
• Pressure.
Testing
requirements
specifications,
and
traceability
must
be shown
establishing
the materials
between
the
characteristics
in
and the test results.
Coupon
the following
tests are conducted
discipline
areas:
•
Ultimate
•
Yield
•
•
Fatigue
Fracture
•
Environmental
Where
by the materials
strength
strength
life
required,
Component
compatibility.
these tests must include
qualification
and acceptance
temperature
testing
and environmental
was discussed
under
effects.
similarity.
103
Dynamictests are required
sion, aeroelasticity,
to validate
and loads. Models
mentioned
disciplines
to perform
duplicate
the dynamic
characteristics
frequencies
are outside
closely
spaced
accurate
data. Judgment
judgment.
Dynamic
instrumentation,
conditions
random,
mode
selections
correlation,
and verification
of the system.
range
of the basic
be used
as to which
boundary
criteria,
data
are either
modes.
fixed,
fixed
sine sweep,
from the test for modal
the
Also,
too many
modal
systems.
hinged,
or free-free.
Excitation
and impulse.
Model
testing
verifies
applies
the external
These
the dynamic
range
and
mass
tuned
or
to get
quantity
this
and
locations,
Testing
boundary
methods
assurance
from frequency
stiffness
helps
or
whose
it hard
methods
evaluation
sine dwell,
correlation.
making
analysis
excitation
and
must simulate
dynamically
data,
Sensitivity
conditions,
collection,
Pogo suppres-
can be used for components
basic
are important.
consider
design,
The test hardware
simulators
can contaminate
system
based on the tests, then used by the above
analysis.
Mass
must
random,
model for control
and updated
goodness
etc. Dynamic
analytical
are single-point
criteria
accuracy
are used
to modal
distribution
for
cross
assumed
by the
modeler.
Strength
stiffness
along
must
tests
in general
their design
frequencies
modal
multi-point
are corrected
the frequency
component
the dynamic
verification
assumptions
with critical
and the critical
failure
to limit load plus some
Aeroelastic
aerodynamic
testing
wind
the appropriate
Proof
modes.
margin
tunnel
scaled
testing
As discussed
below
and rotating
machinery.
environment,
verifying
If the structure
previously,
is tested
if protoflight
yield. The correlated/updated
margins.
This
test. The structures
discipline
must design
frequencies
mission
required
of fracture
lifetime.
to predict
pressure
to failure,
model's
margins
static
are verified
is tested
is then used to predict
margins.
as an integrated
structures/
is accomplished
the scaled
wind
tunnel
model
to have
which
will lead
for pressure
vessels
flutter.
data, establishing
Proof
the analytical
test is used, the structure
model
flutter
takes advantage
in a prescribed
load paths.
establishes
modal
to failure
loads
that no flaws are present
testing
is used extensively
c. Analysis.
Verification
basic
approaches
(in particular
design
safety
by analysis:
factors
are used to cover
the test response,
Structural
independently
been
met.
an acceptable
verification
uses
model
the
or interdependently.
If requirements
operational
three
Structural
are not met,
constraints
uncertainties.
three
failure
modes
Models/analysis
utilization,
approaches
verification
options
and procedures.
in today's
exist:
environment.
are benchmarked
structural
instrumentation
above
approach
(1) Models
test) and then used to predict
predicting
either
(3) implement
is becoming
used for verification
protoflight
verification,
104
by analysis
loads
or correlated
and margins
(1) Redesign,
are two
using
testing,
when
in test
etc.
and
analysis),
the requirements
(2) waive
tests
and (2) larger
also play a key role
application,
(similarity,
is complete
There
requirement,
have
or
THERMAL
J
System
.r!t
iţ
AerodynamJcs
41
Trajectory/G&N
i
Control
.!l
!
|
_
Structures
I/
t
Thermal
i
t
,
i#
Propulsion
i1
t
_
Avionics
I
iJ
Materials
1
',,...................
_6
t
j
4.3.7
Figure
53. Design
Design
Function
Thermal
The connection
between
Manufacturing
_
Other
process
technical
the design
process
delineated
in figure
53. The illustration
the
design
functions.
other
_
In
depicts
addition,
consists
thermal
of determining
transfer, achieving
design
design
of insulation,
the relationship
thermal
providing
states
attributes.
(with
propellants,
components,
for stress fields
input
from
and
These
and
fatigue,
function
process
An important
and
is
success.
It
the heat
activities
provide
that
is
The details
predicting
design
systems
crew.
function
its operational
aerothermal),
The thermal
TCS's.
payloads,
the thermal
design
verification.
for fracture,
design
and assess
environments
temperatures
the thermal
design
flow
the thermal
and compartment
and the thermal
between
to the vehicle
and component
function.
work/information
is fundamental
for structures,
structural
the
to develop
and providing
design
integration
activity
the thermal designs,
TPS,
technical
it shows
supported
by key thermal decision gates required
of all the above are delineated
in this section.
The
integration--thermal
_. ,.._
provide
the desired
function
is
and deflection.
105
4.3.7.1
depicts
Thermal
the thermal
design
with requirements
procedures,
and the thermal
functions
heat
thermal
transfer,
from these
TCS design.
Function
flow and various
and criteria.
the discipline
Outputs
Design
in conjunction
response,
activities,
The
interacting
definition.
As in the other planes,
More details
to requirements.
system
Plane.
design
discipline
Following
functions.
matrix
plane.
environments
of the tasks are in later sections.
the design
iterations
cannot
solve
The major
for such
balances
to achieve
overall
convergence.
The design
system
discipline
things
philosophies,
functions
the inputs
of the thermal
otherwise
design
becomes
involved
plane
flow starts
by
shown
as compartments
become
54. It
are developed
is complete;
then the system
in figure
process
The attributes
the design
the problem,
is shown
and uncertainties
as well as inputs from other disciplines,
If they meet the requirements,
plane
these are the thermal
the parameter
with the system
and thermal
thermal
and
are
tanks.
for the TPS and
design
are compared
iterations
occur. If
with trades
0
and
:2
{ntegration
_
Thermal
Thermal
Thermal System
Definition
Requirements
and Constraints
Parameter Matrix
and
Uncertainties
Philosophy
Procedures
Thermal System
Criteria
_,_
1
Yes _
(Stop)
_
No
(Iterate)
_,
Thermal Attributes
• Deflections
• Material Limits
Tps
and
Thermal
Design
• Compartment
Environments
• Cost
• Reliability
• Operability
._
Transfer
Heat
._
Response
Thermal
IThermal Environment I
I
"_-]
_
Figure
The thermal
requirements,
illustrated
thermal
and
process
one-way
on the thermal
design
thermal
plane
design
(shown
areas.
of the inputs
is provided
in the following
from
design
reference
2 is shown
and outputs,
design
delineation
106
flow
inputs
54. Thermal
plane.
and two-way
The process
as heat transfer,
The
NxN
and outputs
diagram
associated
para_aphs.
etc.).
function
in figure
Depicted
of reference
and Tests:
Combined
Special Analyses
Environments
55. External
These
the details
are the analysis
2 (Appendix
with the thermal
L_
I--
plane.
inputs/outputs.
flow represents
Compartments
Tanks
design
inputs
are shown
are the details
of the discipline
tasks,
thermal
A) is representative
function.
More
detailed
as
of what
is
flow of the
design
data,
of further
discussion
Internal Flow
Requirements
• Programs/Project
• Concepts
• Constraints
• Designs
I Consultation I Options I T'a, les I Analysis I Cosl I
L
[
|
.....
............r-
"-
l_
Inputs (One-Way)
• Natural Environments
• Safety
Outputs(One-Way)
• Ground Operations
Inputs/Outputs (Two-Way)
• Performance and Trajectories
• Aerodynamics and Induced
Environments
• Structural Analysis
• Vehicle Configuration
and Structural Design
• Materials
• Propulsion
• Communications and Data
• Mass Properties
• Flight Operations
• Cost
• Reliability
Figure
Thermal
Thermal Design Data
• Material Selections
• Establish TPS Split Lines
• Establish TPS Thickness/Sizing
• Establish Insulation Location/
Thermal Design
• TPS
-Aerothermal
-Base Heating
-Control Surfaces/
Thickness/Sizing
• Determine Minimum/Maximum
Leading Edges
Insulation
-Tanks
-MPS Components
Structures
Gates.
55. WBS
2.5--thermal
flow. 2
gates
for the thermal
design
process
the design
of TPS,
to produce
temperatures
environments.
design
discipline
gates
plume
aero heating,
and
components
such
design
(tank
Interactions
with other
disciplines
If the gates cannot
trades
and balance
requirements.
have
the
required
accuracy
Thermal
propellants
gates.
reliability,
integrity.
condition
be met through
Foremost
to predict
informal
in the thermal
thermal
and sensitivity)
but also the
in that it must
protect
from
environments
for
(margins
is complicated
and provide
interactions,
characteristics.
56.
gates
are a fundamental
gates
in figure
and TCS and to output
insulation),
design
are shown
insulation,
must pass not only the performance
as structural
and crew.
Compartment Conditioninc
TCS (Active/Passive)
process
The decision
and compartmental
TPS Sizing
Cryogenic Insulation
Sizing
Structure Temperatures/
Gradients
TCS Sizing
Compartment
Environments
Thermal Design
design
All these gates must be satisfied
The thermal
Products
Temperatures
Determine Structural Gradients
Fluid Selection
Heat Rejection Modes
Special Components
Overall Thermal Integration
Thermal Interfacing Definition
Establish Compartment
Environments
Handling
• Electrical Power
4.3.7.2
Thermal Models/Analysis
• Environments/Properties
Data Base
• Develop Models/Analyze
- TPS
- Cryogenic Tanks/Insulation
- Main PropulsionSystem
(MPS) Components/Insulation
- Structures
- Compartment Conditioning
- TCS (Active/Passive)
- Integrated vehicle
thermal
part of meeting
the system
is that the thermal
Other
gates
plane
model
include
structural
the thermal
is used
to make
must be shown
acceptable
to
cost,
and operability.
107
Environments
Compartments
Criteria
,_
TPS Design
Insulation Design
TCS Design
Structural Temperature
Compartment Environments
, No
!
I
I
Systen
Operability
'No
I
kerodynanTic_
Yes
Thermal
Analysis
_. No
Yes
_
Reliability
t_No
Tests
, Thermal Requirements
and Constraints
• Thermal Configuration
• Philosophy, Procedures
NO °i
I
I
and Criteria
Yes
I insulation
Criteria
Figure
4.3.7.3
the discipline
actions,
discussed
Tasks.
tasks
The
depicted
Shown
in table
and
the tasks.
from
reference
gates.
2 are shown
plane,
figure
14 are the top-level
thermal
design
function
tasks
to illustrate
primary
Task
and other design
criteria
for thermal
thermal
system.
108
tasks
function
design
systems
on the
WBS
design
thermal
This task
in the following
4.3.7.3.1
thermal
56. Thermal
matrix
is provided
in table
13. These
tasks
delineate
54.
including
the activities,
the inter-
interacting
activities
technical
paragraphs.
1--Requirements
design
Associated
functions
Determination
to jointly
application.
define
As a part
with this are the design
and Allocation.
and allocate
of this activity,
philosophy,
the systems
Task
a preliminary
parameter
1 is a joint
and thermal
definition
definition,
activity
with
requirements
and
is made
of the
and uncertainties.
Table13.WBS 2.5--thermal designtaskdescription.2
Inputs
Tasks
•Projected groundrules
*Design-to-costgoals
•Preliminary design concept and data base
•Launch pad environments
•Configuration details, materials,
dimensions
,.,*Ascent, cruise, loading requirements
•Ascent aeroheating histories
• Entry aeroheating histories
•Compartment flow rates
• Plume heating environments
•Temperature gradient design limits
• Mass properties control plan
• Documented control weights
•Weights, centers of gravity, moments
of inertia
• Ground hold conditions
• Heat load requirements for propellant
conditioning
*Chill down requirements
.Engine configuration
• Engine operating characteristics
.Engine thermal requirements
.Material thermal properties
•Material allowables
m Material selection consultation
,.,- TPS vehicle interface definition
,,,. Material thermal required
.Thermal design limits
.Sensor characteristics
.EPS operational environment
requirements
•Vehicle integrated OPSconcept
and requirements
.Hazard analysis
-Fault tolerance requirements
-Failure mode effects analysis inputs
,--CIL inputs
• Hardwaredesign, development, testing,
evaluation, and production costs
• Cost trades
Key:
Outputs
3.6.1
Review PhaseA results
3.6.2
Establish properties data base
3.6.3
Analyze thermal design concepts
- TPS
-
Cryogenic insulation
-
Compartment thermal assessment
-
TCS (active/passive)
MPS
3.6.4
TPS sizing
3.6.5
Cryogenic insulation sizing
3.6.6
TCSsizing (active/passive)
3.6.7
Compartment thermal environments
3.6.1]
MPS thermal sizing
•Ternperature sensor
locations
,-, Wall/surface temperatures
•Heating rate or temperature
indicators
•Heating constraints
•* Wall/surface temperatures
•Structural temperatures
and gradients
•TPS sizing (aerothermal/base
heating)
•Cryogenic insulation sizing
•Active TCS sizing
•Component weight estimates
•Parts list
• Propellant condition
•Temperature time history
.Pressure
•Chilldown of engine
•Temperature and heating loads
• Structural temperature
requirements
•Thermal environment
•Thermal environment for EPS
•Power requirements for
thermal control system
•Structural temperature
requirements
•Subsystem definition and design
description document
•Environments and loads definition
Tools:
• Commercial software--SINDA and PATRAN
• In-house software
•Materials type
•Technical descriptions
•Test requirements to include
instrumentation
•Production quantities
• Make or buy plan
• ELV,RLV,and RBCC
•,, RLVand RBCC
,,_ RBCConly
4.3.7.3.2
Task 2--Thermal
Analysis.
in conjunction
with the design reference
the heat transfer, thus the temperature
• Thermal
environments
considering
and tanks,
as well as human
• Heat transfer
characteristics
• Thermal
response
Task 2 utilizes Task
1 requirements
and preliminary
definition
trajectory and the predicted external thermal environments
to calculate
of the structure. The task evolves into three distinct analysis areas:
radiation,
environments,
of the system
convection,
payload
to the thermal
and conduction
conditioning,
for the compartments
etc.
environment.
109
Table
14. Primary
Activities
tasks
for thermal
design
Interactions
Tasks
1. Requirements
determination and
allocation
Mass properties
System
Aerodynamics
Propulsion
Trajectories
Structures
1. Consult with system to obtain operations philosophy, constraints,
cost, etc.
2. Obtain definition of configuration.
3. Provide to systems plane discipline peculiar criteria for formal/
legal application.
4. Develop thermal verification requirements.
5. Develop thermal requirements into gate matrices.
6. Flow up derived requirements to system.
2. Thermal analysis
Aerodynamics
Propulsion
Structures
Trajectories
1. Set up describing equations for each of the separate subsystems
and mission events.
2. Develop all input data and execute various thermal analysis.
3. Work with interacting disciplines to resolve anomalies, etc.
4. Consult with system to resolve remaining issues.
5. Insure that cost, reliability, etc., are included in trades, etc.
1. Using system requirements, thermal analysis results, etc., design
the TPS outputting design specifications to serve as the baseline
for the next design iterations or for verification.
2. Using system requirements, thermal analysis results, etc., design
the TCS outputting design specifications to serve on the
baseline for the next iteration or for verification.
3. Thermal system design
4. Verification
These
Test
Trajectories
Stress
data
become
conditioning,
and
compartments,
on structure
include
stresses,
1. Work with interacting disciplines to determine test facility
requirements, test conditions, instrumentation, and data
system requirements.
2. Work between disciplines to accomplish verification test.
3. Work between disciplines to evaluate results.
4. Flow up anomalies for resolution and operational procedures
definition.
5. Final thermal verification achieved in development flights.
inputs
for
and
structural
for
deflections,
communications
design
functions.
This
system
may
a regenerative-cooled
use
with
the
close
thermal
and
the
trajectory,
interaction
includes
design
design
materials
of
materials,
structures,
both
data
nozzle
input
or an ablative
and
regenerative-nozzle
analysis
includes
flow
circuits,
boundary
The
analysis
combines
heat
transfer,
gas
to determine
nozzle
thermal/materials
characteristics.
life
support
for thermal
changes.
data.
systems,
effects.
Execution
propulsion,
output
nozzle
etc.
ablative
TPS,
to account
property
The
110
function.
Thermal
of this
avionics,
For
and
task
effects
requires
aerodynamic
example,
the
propulsion
special
analysis.
where
each
requires
layers,
film
coefficients,
pyrolosis,
materials,
dynamics,
payload
heat
transfer,
erosion,
etc.,
4.3.7.3.3
Task 3--Thermal
systems.
These
thermal
designs
System
include
Design.
for propellant
• TPS for aerodynamic
and plume
heating
• Life
environment
system
support
thermal
and passively
• Solid rocket
motor
insulation
and component
Thermal
interfaces
design
thermal
and informal.
As the design
the specialist's
criteria.
by temperature)
must
environments
disciplines
and/or
systems
Usually,
evolves,
be met. The
materials
limits.
these special
thermal
(includes
functions
avionics
structural
margins
performance
gates
Cost and operability
and ablative
components).
and with systems.
the gates for completion
For example,
such as life support
determine
conditioning
with the other design
mance
for the special
nozzles
and heat protection
both formal
thermal
conditioning
cooled
• Compartment
(influenced
of the various
conditioning
nozzles
• Regenerative
and
for the design
at least the following:
• TPS and insulation
• Payload
• Ablative
This task is responsible
exchanges
are a combination
for strength,
usually
have
are additional
nozzles.
These
The system,
are
of the perfor-
fracture,
and
fatigue
to do with the resulting
gates.
Special
the design
gates exist
function,
and the
gates.
If the informal
approach
cannot achieve an adequate
design, then the system design function must provide the appropriate
to achieve the best design. Engineering
judgment
plays a central role in the balancing
act.
balance
4.3.7.3.4
gates are worked
Task 4--Verification.
are for both components
many
thermal
motor
and hot-gas
hot-fire
tasks
facility
process.
models
approximations;
Verification,
testing
and conducting
verification
Proper
therefore,
verification
components.
high-fidelity
ground
component
the test
chambers.
plume
tests. These
and environments
must
limitations
be well
tests include
and solid rocket
tests are essential
be ensured.
tests
As a result
Other
impingement
and subsystem
must
using
the environments.
vacuum
and propulsion
(SRM)
conditions
is achieved
to duplicate
in thermal
motor
therefore,
disciplines.
generally
The tests are designed
for aeroheating
boundary
requires
• Environments
with the various
must be accomplished
test beds for solid rocket
Designing
are
Thermal
and subsystems.
verification
wind tunnel
informally
to the
All tests as with all
understood
and
challenged.
the following:
definition
• Component
definition
• Test constraints
and fixtures
• Instrumentation
• Test conduction
and data systems
requirements
• Test data evaluation
• Correlation
The
of analysis
verification
the requirements.
very important
Final
to test data.
of the thermal
verification
that the development
design
is achieved
when
can only be accomplished
flights
have
proper
the analysis
during
instrumentation
and hardware
developmental
and data
flight
test data meet
testing.
It is
systems.
111
PROPULSION
System
Aerodynamics
Trajectory/G&N
Control
Structures
Thermal
Propulsion
Avionics
&
Materials
Manufacturing
II
Other
Figure
4.3.8
Propulsion
The
57. Design
Design
connection
between
is delineated
in figure
function
and the other
design
112
technical
integration--propulsion
design
function.
Function
function
supported
attributes.
process
the
design
process
57. The illustration
functions.
In addition,
by key propulsion
decision
gates that
The details of all the above are delineated
technical
depicts
integration
the relationship
it shows
and
between
the work/information
are required
to develop
in this section.
and
the
propulsion
design
the propulsion
design
flow process
assess
the
which
propulsion
is
(Note:
Design
subsystems
and
provides
a top-level
liquid
engine
mechanics
very
complex.
etc.,
conversion
the
structural
the
performance
design
the engine
ignition
including
design
can
weight
with
dry
into
system
process
describe
the
its relationship
and
interaction
in itself,
involving
design
process
propulsion
the
vehicle
solids,
etc.)
is, therefore,
numerous
in detail
with
the
total
vehicle
design
the
structural
design
as well
between
these
Function
is illustrated
elements.
engine
These
system.
the
payload
into
system.
The
propulsion
the
desired
and
propulsion
the
flight
with
three
into
source
focus
but
using
a
top-level
This
figure
propulsion
discipline
functions.
system
report.
and
the
This
rest
of the
Choice
of the
design
from
(1)
Structural
(dry
mass)
(nonideal
effects).
a liquid
engine
system
(for
activities
devices,
chart
the
lines,
on
design
of
ducts,
valves,
its own
design
design
process
would
is provided
because
of the
requires
propulsion
launch
by
Vehicle
subsystems
The
orbit.
orbit
converts
system.
as separate
top-level
system
is
influence
combustion
of these
a specific
areas
a strong
propulsion
shows
design
as the
has
areas:
of losses
The
in this
clearly
mechanics
are turbomachinery,
Each
presented
payload
energy
(3) management
58.
of the supporting
process
a given
and
Plane.
in figure
interrelationship
propulsion
determine
and
with
as putting
concerned
efficiency,
function
and/or
efficient
they
coupled
The
characterized
a highly
together,
Design
between
etc.).
pushing
system
to the design
response,
engine,
Coupled
the
is strongly
be
Propulsion
and
system
thrust,
all of the interactions
interaction
is a complex
not
(liquid
standpoint
subsystems
system,
be comparable
strong
control
(2) propulsion
example)
to show
(trajectory,
energy
4.3.8.1
does
report
propulsion
system.
efficiency,
This
of the
Vehicle
energy
subsystem
as an example.)
minimum
chemical,
propulsion
overview
design
flight
the
specialties.
system
The
achieving
of
vehicle.
Informal
_
_lntegration ;;
Requirements
and Constraints
ro0
t--Iro
,s,on
]--l
u,s,on
er'° m
Procedures
Criteria
Approaches
Configuration
Definition
Parameter Matrix
and
Uncertainty
Tankage System Design
(Stop) I (Iterate)
Propulsion System
Attributes
• Thrust to Weight
(T/W)
4
-d
Turbomachinery Design
Combustion Devices Design
Lines, Ducts, and Valves Design
• Isp
• Size
• Strength
• Endurance
• Cost Factors
• Reliability Factors
i[
• Complexity Factors
• Failure Modes
Figure
58.
-4
Ignition System Design
Propulsion
design
function
F
I-I-I-F
and
Layout
Propulsion
System
Design
plane.
113
This
strong
the other
system
and
design
functions
mance
attributes.
the propulsion
The
allocation,
Section
interaction
results
such
functions
of the vehicle
involved
also in the system
For example,
process
starts,
then proceeds
with the associated
as it has
for each
to the parameter
this generic
Figure
59 from
reference
limited
process
flow. The process
design.
The detail
designs
to generate
of the attributes
as trajectory,
trades
which
structures,
balance
the amount
of the propulsion
and control.
requirements
of payload
These
and perfor-
to orbit and the size of
cost.
other
definition,
planes,
then
with
requirements
definition
and
to design
the system,
subsystems,
etc.
process.
2 shows
the inputs,
flow only shows
for the
requirements,
supporting
and its subsystems
shown.
system.
the same pattern
outputs,
the activities
system
activities
the propulsion
2 (app. A) follows
of the
matrix
of the propulsion
the data
in designing
balancing
there may be a trade between
systems,
discusses
reference
and
design
and structural
accomplished
trades
are heavily
4.3.1
required
in many
It is assumed
The propulsion
shown
system
and products,
structural
design
are not shown;
that these
entry
as well
and trajectory
however,
complex
as a
they are
activities
on the NxN diagram
are
from
previously.
Internal Flow
Requirements
Program/Project
Constraints
Concepts
,,....
k
L
r
..............
Inputs/Outputs (Two-Way)
• Vehicle Configuration
and Structural Design
• Performance and Trajectories
• Aerodynamics and Induced
Environments
• Structural Analysis
• Thermal
• Guidance and Controls
• Materials
• Communications and Data
Handling
• Electrical Power
[
• Ground Operations
• Flight Operations
• Manufacturing
• Safety
• Reliability
• Cost
Figure
114
Products
Feed System Geometry
• Tank/Feed System Analysis
,* Tank/Feed Fluids
_. Pressure Analysis
• Schematic Drawings
-Lines
-Ducts
-Valves
-Components
• Designand Layouts
• Weights, Parts List
• MPS/Engine System
• Propellant Inventory
• Ullage Requirements
• Lox/Fuel Feed Geometry
• Net Positive Suction
Pressure (NPSP),
Pressure Drop
• Propellant Conditions
• Fluid,Thermal, Pressure
Models
FPR, Start/
Shutdown Transient
• Propellant Inventory
Hazards
Benefits Reliability
Operability ] Maintainability
Cost/Makeor
Buy
ResourcesI Feedback
RequirementsTest
/ I Algorithms
S/W
I Needs
Servel
Utilization
Requirements
Materials/
PartsList
59. WBS
Technica' ISizing/
Descriptions
Confi_ur,a,tion I
2.8--propulsion
system
Conceptual
Sketches/Layouts
design
process
flow diagram.
2
4.3.8.2
Propulsion
Gates.
Figure
60 illustrates
the propulsion
system
decision
gates.
The
gates
the propulsion
system must meet include Isp, thrust, thrust to weight, and volumetric
constraints,
as well as
the normal discipline
gates associated
with the discipline
functions.
Examples
are control system stability,
turbomachinery
stability
gates
with propulsion
associated
and vibration,
thermal,
system
structural
strength,
and durability,
as well as other pertinent
design.
• Drawingsand
Specifications
• Thrust
_
Operability
• Isp
• Size
• Weight
i..N° ..............
_
_ines,Valve Combustion
andDucts
Devices
Reliability
i
t.No
TurboMachinery
AcceptableJ
Propulsion
(Engine)
Software __
aequirementsl NoY
Tankage
Ignition
PropulsionRequirements
• Philosophy/Approach
• Geometry
• Mass
Performance
Acceptable
•
• Isp
No
• ThrustandTAN
.,,.
...................
No..
,
i ......
Yes
Figure
The
ability
propulsion
to efficiently
the vehicle
decision
convert
performance.
volume,
etc. The engine
to these
performance
components
must
Additional
thoughts
many
crucial
trades
chemical
system
and
Acceptable I
Strength,
Endurance
I
Stability
I
60. Propulsion
gates
Implied
meet
i
include
energy
function
into propulsive
requirements,
gates
the propulsion
system
the engine
performance,
which
energy
(thrust)
at the level required
are the additional
factors
of weight,
and operational
the propulsion
requirements
are in section
gates.
foremost
must also meet cost, reliability,
all the discipline
between
first and
in this statement
program
on these
design
such
4.3.6.2.
The
system,
requirements.
its subsystems,
as strength,
fracture,
major
to remember
point
and the rest of the vehicle
thrust
fatigue,
that result
is its
to meet
to weight,
In addition
elements,
and
thermal,
etc.
is that there
are
from attempting
to
meet their respective
gates. It should be remembered
that the propulsion
system provides
the energy to
achieve orbit. In achieving
this requirement,
it dictates
much of the structures
design. For example,
the
liquid
propellant
that transmits
propulsion
tanks
through
system
and lines transfer
the chemical
thrust
to the tanks,
greatly
frames
influences
back
the dry weight
potential
energy
etc., to achieve
(mass
fraction)
to the engines
vehicle
kinetic
of the system.
that produce
energy.
The
vehicle
thrust
Thus,
the
cannot
115
weigh
too much
are too high.
refurbishment
or it is too costly.
4.3.8.3.
Propulsion
4.3.8.3.1
Task l--Requirements
are many
tasks
required
to design
15. They
include
design
components.
general
15, is limited
The
discussion
integration
tasks
activities,
posed of many
requirements
system.
design,
subsystems
requirements
levels;
and sensitivity
configuration
definition
information,
along
data
selected;
to make
combustion
system
to some
extent
design
are available
starts
follows
the
same
fluid
dynamics,
propulsion
requirements.
Since
system
thermal,
meet
stress,
dynamics,
all its engine
the propulsion
system
ends
specific
fatigue,
gates
removing
up influencing
and pressure.
are flowed
propellants
Propellant
utilization
and managed).
during
extended
This
includes
the provision
holds.
A major
factor
transfer
system
allocation,
to propulsion
116
and allocated
The subsystem
a gas generator
planes.
has been chosen
along
and that
with the preliminary
propellants,
etc.). This
process.
fracture,
first from
etc.
the systems
plane
must
a large
is an important
and arrangement)
of engines
and the
acceleration.
The first task of propulsion
subsystems,
the
system is com-
compartmentalization
but
system, this interface is very important.
Propellant
tanks, for example,
of the structure,
carrying loads as well as propellant
and conditioning
propellants
show
versus
and oxygen
the design
engine
with the systems
and structure
system
in
devices.
combustion
liquid hydrogen
requirements,
and
the charts
the propulsion
manufacturing,
defined
At top level,
must then be distributed
that the propulsion
allocated
planes,
and combustion
the selection
cycle,
tasks.
with an interaction
e.g., staged
from the materials,
it is assumed
devices,
these
There
approach
previously.
Subsystems
include
engine
systems,
line and ducts, valves,
turbomachinery,
devices, nozzles,
control, etc., each requiring
its own design specialties.
Key disciplines
are
rotordynamics,
temperature
and
WBS from
for the tasks
combustion
design
starts
requirements
with the above
Propulsion
and cost
functions.
discuss
plane. Because
to turbomachinery
concept
interaction
(i.e., staged
functions,
to the propulsion
generated
will briefly
system
design
the inputs
16. As with the other
for example
that is to follow,
and produce
turbomachinery,
these top-level
by the engine
there is a strong
the trades
operations
The propulsion
with the other vehicle
paragraphs
in table
and elements,
subsystem
In addition,
the
system,
as all other design
In the discussion
must
of the engine
system
system
are modified
discussed
combustion
the propulsion
are shown
and Allocation.
that interact
in the following
and allocate
to the propulsion
Determination
to a set of tasks
and the tasks.
Propulsion
or, again,
well-defined,
efficient,
and effective
maintenance
part of the propulsion
system gates and tasks.
the interactions,
plane to determine
be too expansive
Tasks.
2, table
technical
cannot
Reusable
systems
also require
characteristics.
All these become
reference
table
Its geometry
combustion,
satisfy
Not only
percentage
of the total structural
compose a large volume and weight
the propellant
in terms of at least
part of the design
for dumping
in vehicle
design
then from
(how,
when,
propellant
is accommodation
of the energy
(thrust)
efficiently
design is, therefore,
the requirement
plane,
etc.
the vehicle-imposed
the propulsion
etc.,
the
for aborts
or
(location
to provide
vehicle
determination
and
plane
to its various
Table
15. WBS
2.8--propulsion
task description,
Tasks
Inputs
Outputs
• Projectedgroundrules, design-to-cost
goals
• Technologyrequirements(TRL level)
• EngineI/F
• Redundancyrequirements
• Programmatic constraints
• Launchpad environments
• Vehicleconfiguration
andtank geometry
• Line routing zones
• Pressurantbottle locations
--Preliminary air column
.,-Profile
• Vehiclemassversustime
• Thrust,accelerationand pressure versustime
3.9.1
• lsp(flow rates)
• Usablepropellantrequirements
• Axialacceleration
• Dynamicpressures
• Flowrates
•System dispersiOnS
• Wind dispersions
Air inlet constraints
'...Derived air volume
• Air loads on propulsionelements
- Engineinstalledthrust
_Forebody pressure recoveryand flow
field definition history
• Structural analysisof lines and brackets
• Establish dynamic envelopof feedline
• Determineline thickness
_Aft/forebody structures
• Propellant condition
• Temperaturetime history
,Pressure
• Chilldown of engine
• Temperaturesand heatingloads
• Pogo suppressorrequirements
• TVArequirements
• RCSrequirements
• Mass propertiescontrol plan
• Weights, centersof gravity,moments
of inertia
• Material compatibility
• Contaminationanalysis
• Material properties
•Thermal and cryogenicproperties
• Temperaturelimits
•Telemetrycapability
• Sensorcharacteristics
•Availability of power (current, voltage,phase)
•Operationaltimelines
• Maintainability
• GSEcapability
• VehicleintegratedOPSconcept
and requirements
• Flight timellne
oFabficafionparameters
• Flight safety review of schematicand OPS
• East and west test range interface
•Hazardanalysis
• Fault tolerancerequirements
• Reliability allocationand estimation
• Failure mode effectsanalysisinputs
--ClL inputs
• HardwareDDT&Eand production costs
•Cost trades
3.9.5
TVC componentsand
1396
Propulsion system schematics andlayout
Key:
3.9.2
Establish baseline teed system geometry
Analyze tank/feed system fluid, thermal issues
-
Temperature profiles
-
Cryo fluid management
-
Pressure drop, NPSP availability, water
hammer
-
Residuals ullage
-
Propellant inventory
3.9.3
Pressurization system sizing and design
3.9.4
Valves, ducts, mechanisms design, and layout
drawings
design
drawings
3.9.7
z
Testing engine/propulsion component
Tools:
• In-house software
• Fluid flow models--cryo fluid management thermal
models
• Testing
• Commercial software--CAD layout/drawing packages
• Propellant inventory
• Propulsion system layout
• Tankpressures
• Propellant level sensor locations
--Forebody moldline (iteratereq air volume)
--Staging requirements
--Propellant requirements
--Numi_er of engines
--Performance updates
- Entry propellant weight
• Propellantload
• Engineperformance(Isp,thrust)
--Expected engine roachtransitions
--Inlet captive volume
,.,,Recoverypressures
--o_, for inlet airflow as a function
of roach number
--Mach transitions
• Enginedimensional and operational
characteristics
• Turbine exhaust definition
• On-padeffluent definition
--RBCC exhaust conditions
--Forebody inlet performancerequirements
• Ignition and shutdown thrust transients
and timing sequences
• Steadystate thrust oscillation
• Ullage pressure and tank fill heights versus
flighttime
•..RBCC exhaust/thrust
• Ground hold conditions
• Heatload requirementsfor propellanl
conditioning
• Chill down requirements
• Engineconfiguration
• Engineoperating characteristics
• Enginethermal requirements
• TVCgimbal capability (degreeand rates)
• Feedlinelayout
•Kinematicanalysis
• PU system definition
--Air capture transition
• Propulsion system drawings and models
• Componentweight estimates
• Parts list
• Life limits
.Instrumentation
• Uplinlddownlink requirements
• Driveelectronics
• Electricalpower requirements
• MPScheckout and fill
• Refurbishment/inspectionrequirements
• Verification requirements
• Transportationrequirements
• Subsystemdefinition and design
description document
• Vehiclecontrols
• Powerusage
--Flight rules
• Drawingsand schematics
• Hazard analysisinputs
• Functionalfailure model
• Failurepropagationlogic development
• Diagnosticstcontrotlogic
• Failure mode effectsanalysisinputs
--CIL inputs
• Technicaldescriptions
• Vendor quotes
• Testrequirements tOinclude
instrumentation
• Production quantities
• Makeor buy plan
• ELY, RLV, and RBCC
•- RLV and RBCC
-.. RBCC only
117
Table
Activities
118
16. Primary
Interactions
tasks
for propulsion
design
function.
Tasks
1. Requirements
determinationand
allocation
Systems
Turbomachinery
Combustion
Valves, ducts
Structures
Thermal
Flow
Control
Trajectory
1. Work with systems to flowdown requirements to propulsion
including thrust, Isp,T/W, geometry, tankage, etc.
2. Work with propulsion subsystems to allocate requirements for
design and verification.
3. Provide to systems, discipline peculiar criteria for formal/legal
applications.
4. Develop verification requirements for systems as well as
propulsion subsystems.
5. Developmetric flowdown for use by design function gates.
6. Flowup derived requirements to system.
2. Enginesystem design
Flow
Thermal
Combustion
Turbomachinery
Controt
Structures
Testing
1. Determine engine performance characteristics flowdown/allocate
requirements to subsystems in conjunction with subsystem inputs.
2. Develop propellants, usage requirements, and coordinate with
structural airframe design.
3. Estabtish proputsion systems devetopment and verification
ground-test and flight-test program in conjunction with systems
plane, propulsion subsystems, and disciplines.
3. Engine subsystemdesign Propulsion systems
Materials
Flow
Thermal
Manufacturing
Testing
1. Design combustion devices to meet vehicle systems and engine
systems requirements and discipline criteria.
2. Design turbomachinery to meet vehicle systems and engine
systems requirements and discipline criteria.
3. Design lines, ducts, and valves to meet vehicle systems and
engine systems requirements and discipline criteria.
4. Devetopground test programfrequirements for each subsystem.
4. Verification
1. Developfacility (test stands) requirements and implement in
conjunction with engine system, subsystems, and disciplines.
2. Coordinate hotfire test requirements with engine systems and
subsystems and disciplines including instrumentation, data
systems, and test profiles.
3. Run ground test program (hotfire) in conjunction with engine
system, subsystem, and disciplines, obtaining and coordinating
data for development, verification, and acceptance.
4. Develop plans for qualification and acceptancegates with engine
systems, subsystems, and disciplines for static and dynamic ground
test that includes, at least, flow, modal, fatigue, strength,vibration,
and thermal.
5. Run ground test programs (static and dynamic) in conjunction
with engine systems, subsystems, and disciplines obtaining and
coordinating data for development, verification, and acceptance.
6. Establish the constraints, maintenance, and operations procedures
from results of test program.
7. Final propulsion system validation is achieved in developmental
flight tests.
Propulsion system
Dynamics
Stress
Thermal
Manufacturing
Systems
4.3.8.3.2
propulsion
result,
Task 2--Engine
system.
during
systems
System
This design
design
and development
tests be used to evolve
component
tests
accepted
in single
determining
The engine
System
design
Analytical
of liquid
propulsion
systems
They can range
evolves.
Then,
finally,
system
models
it is mandatory
from air- and water-flow
propulsion
test stands.
systems
A major
must combine
all of the subsystems/components
and challenging.
How do you start the engine?
that component
and
simulations
activity
to hot-fire
verified,
becomes
one
How
do you
start
due to the use
of cryo
propellants
and engine
conditioning
and purging
shutdown.
Obviously,
of this design
is tying
the valves,
actuators,
igniters,
together
between
the propulsion
system.
The
timing
constraint.
As a result,
Managing
losses
is mandatory.
propellant
and
operations.
balance
Packaging
the engine
system
such as flow losses
Therefore,
capacity
must
between
issue
Matching
the vehicle
flow rate, and pressures
A part
of this sequence
components,
in general,
volume
together
and
the propulsion
system
etc.,
subsystems,
since,
put all the parts
is very critical.
interaction
required,
is also a key
of
system.
do you control
before
to engine
the engine?
into a working
How
ratio?
critical
and
etc.
conditioning
control
shut down
As a
and mixture
part
and
the
to obtain.
developed,
design
design
throttle
metrics,
are
metrics,
complex
acceptance
and designs
are difficult
evaluation
system
is very
complex.
and propulsion
test profiles,
Task 2 takes these requirements/criteria
is very
the design.
as the design
engine
Design.
process
and the propulsion
to the vehicle
system
is engine
after
through
a
etc.,
is very
is a prime
design
ensure
system
flow
that they
work.
to the vehicle
system
system
determines
(then structures),
the
as well as the
thrust, etc., and derived requirements
such as pogo suppression.
attributes
to the system and trajectory
planes. Aerodynamics
Thrust and Isp are provided
as propulsion
and thermal require the nozzle geometry,
thrust,
heating
etc., to generate
propulsion
system
aerodynamics
provides
(mainly
thrust vectoring
It should
be pointed
Eighty
to ninety
percent
of the vehicle
system
provides
the
for
aerodynamics
in addition
communication
functions
out again
power
and vehicle
axial thrust,
drag.
Usually
is propellant
payloads
engines
between
system
which
are thrust
with launch
and the vehicle
drives
to orbit.
the propulsion
Also,
in general,
the
vectored
system,
the structural
Producing
vehicle
are strongly
the
size. The propulsion
power
to provide
system
causes
control
performance.
the vehicle
system,
coupled.
effects
on
thrust
as well as
As a result,
detailed
and
the
other
design
and subsystems.
4.3.8.3.3
Task 3
Engine
Turbomachinery
must
pumps
a high-energy
system
are
propellants.
The first set of gates
rate and pressure.
other
Designing
propellant
become
a another
damping
devices
but
unbalance,
required.
The
turbine
which
gate on bearings
these very
Design.
The subsystemcomponent
the propellants
requiring
at a certain
a large
that
can destroy
power
source
is, therefore,
set of gates.
design
Rotordynamic
dynamic,
destabilizing
Gates
between
and thermal
lifetime
issues,
gates
introduces
and maintenance
the pump
design
vibration
margins
wear
(bearing
is also a pressure
issue
proceeds
As a result
the
to move
the
energy
in terms
the potential
disk mode
as weI1. Beating
the
its performance.
Excessive
stability
including
usually
its performance
is another
forces.
for rotordynamic
and require
to provide
or degrade
stability
the same kind of issues
be prevented
can be a trade
the
task.
machine
a pump
design
flow rate and pressure.
design
this type of high performance
can have
must
complex,
move
also minimizing
etc., is another
etc.,
Subsystem
for turbomachinery
instabilities
margins
blades,
mass
environments.
controllability.
that the propulsion
to the large coupling
is required
and plume
for vehicle
boosting
in parallel.
and
drag)
of flow
for cavitation
These
stability
requiring
not only
prevention
and vibration
instability,
due
to
levels
are
flutter
of turbine
is also a design
issue. The
replacement).
In addition
to
vessel
pressure)
and
(high
119
must
meet
high-cycle
strength
requirements.
fatigue,
fracture,
It also
must
flutter/vortex
meet
durability
requirements
shedding,
acoustics,
and
that
creep.
include
The
therefore,
a very complex
design
problem
with a very stringent
set of gates
from performance,
to strength
and durability.
There
are other
gates
be met,
as weight
some
to balance
trades
vehicle
systems
can be made
which
between
subsystems
a similar
breakout
Combustion
devices
follow
task (combustion).
Due to the shape
can occur,
reducing
or even
fatigue,
efficiency
and fracture.
typical
structure
impacts
the fatigue
types,
Nozzles
shape
needed
gates.
influences
Most
restriction
engine
transients
are produced.
or regenerative.
if the engine
These
weight,
dynamic,
Valves,
issues
hydrogen.
are complicated
lines,
performance
gates,
issues,
compatibility
exist for the design
first
Second,
which
as well
acceptance
120
as the
require
special
tests,
of hot-fire
verification.
of component
SSME
required
ground
test. The engines
can produce
the nozzle
design
thermal
flow
the
structures
parts.
and
other
Stress
tests have
Nozzle
cooling
to control
leakage,
deal with strength,
The nozzle
fracture,
system
design
is always
a combination
at the engine
or refurbished
hot-fire
system
meet
of materials
materials
for some
parts.
thermal
of analysis,
20,000
the
for
and costly,
devices).
design,
etc.,
simulation,
tests. Not including
levels
engine
instrumentation
must meet
(combustion
design,
and
gates.
must
is very complex
systems
flow
fracture,
and fatigue
can be a problem
tests and system
special
be taken
gates
design,
test. Each new engine
to the nozzle.
Because
conversion
is
large
gates.
structural
ratio
thus a
propellants,
chemical
area
conditions,
materials
corrosion
ratio is
start up and shutdown,
design
exotic
the nozzle
a large
Their
and
for certification
also
approach.
of the propulsion
Verification
the
which
Basically,
present.
drive
and element
and hot-fn'e
same
usually
noise
system.
must
strength,
Gates,
create
and vacuum
must
gradients
to predict
instabilities,
They are very strongly
damage
care
as
entity.
During
fatigue
case,
and
fatigue.
conditions,
atmospheric
cooled
Verification
requirements
as well
exit-area-to-throat-area
At vacuum
between
hydrogen
of all engine
instability
by ignition.
of the
in the atmosphere.
all follow
standard
with
combustion
processes
or a separate
as well as the typical
etc.,
of the fluid
performance
and test. The tests consist
of two engines
ducts
especially
to the complexity
developmental
as well as at the
for performance
the low-cycle
performance
of power.
by the large
gates,
exist
At sea level a low nozzle
Clearly
Task 4--Verification.
the high
usually
plane,
factors,
is also complicated
devices
is a compromise
transients
Gates
impact
design
In the regenerative
compatibility
due
to stability,
and gates. The first task is the energy
and other
All combustion
and the overall
These
burns
actuators,
device
level is required
and performance
4.3.8.3.4
areas.
as a function
design
(thrust)
can be passive
fatigue.
gradients
for these
of the engine.
stability
nozzle
on the throttle
particularly
systems
is,
and cost; however,
gates.
Combustion
instability
is difficult
chambers
and devices
are subject to flow
thermal
devices
tasks
the engine.
a part of combustion
the thrust
throat
of design
destroying
The combustion
can be considered
to maintain
required.
shock
Large
are necessary
with the combustion
greatly
and at the engine
of the chamber
stability.
Thrust
and Isp are the performance
analytically,
thus resorting
to test. Combustion
coupled
such
and
plane.
conversion
strength,
must
low-
turbomachinery
all the
seconds
on each
must pass a hot-fire
ground
for adequate
evaluation.
In additionto these engine
• Cold
flow (water
• Dynamic
• Proof
system tests, the following
tests are performed
on elements
and components:
and air)
(model
testing,
spin-pit
testing)
pressure
• Strength
• Fatigue
(low and high cycle)
• Qualification
• Vibration
and acceptance
• Thermal
• Material
characterization
-
Extreme
-
Environments
-
High
Key
hot and cold (near melting
mean
(hydrogen
loads.
also is the use of simulations
control,
valves,
process.
This allows
etc., are coupled
efficient
where
the engine
components
with a computer
simulation
of the other functions
verification
of sequencing,
Analysis
with
test
verified
models
such
as strength.
Many
other
margins
off-nominal
conditions,
to cryo)
embrittlement)
etc. There
analysis
are many
tasks
include
verifications
which
shutdown
sequences,
and purges.
Verification
of the propulsion
system
is, therefore,
very complex
achieved
leading
through
to the requirement
developmental
for safe engine
flight
shutdowns
system
structural
test and analysis.
start sequences,
crucial,
propulsion
are combined
and pressure
manned
such as the combustion
to flight
conditioning,
for high performance
as avionics/
extrapolation
engine
increased
to temperature
to establish
propellant
is greatly
that leads
in general
such
and software.
include
complexity
conditioning
is used
coupling,
and elements
usage.
requirements
and vehicle
on tanks
as touched
In this case,
aborts.
environments,
These
and lines,
on here briefly.
reliability
The
and safety
The final verification
is
is
testing.
121
AVIONICS
System
Aerodynamics
TrajectorylG&N
Control
Structures
Thermal
Propulsion
_,
Materials
Avionics
,_
_
Manufacturing
Other
4.3.9
Figure
61. Design
Design
Function
The connection
Avionics
process
technical
integration--avionics
design
between
the design
process
technical
and the avionics
the relationship
is delineated
in figure
61. The
illustration
depicts
and the other
subsystem
design
functions.
In addition,
supported
by key avionics
The
of all the above
details
complex
process
describe
the avionics
and interaction
in itself,
power
122
instrumentation,
system.
gates
that are required
in this section.
involving
numerous
process
in detail
the avionics
RF/communications,
controllers,
it shows
are delineated
with the total vehicle
In this report,
GN&C,
design
decision
subsystem
includes
data
to develop
subsystems
process.)
management
electrical
subsystem
the avionics
and assess
Design
and
(DMS)
support
design
function
the avionics
attributes.
document
does
is a
not
its relationship
systems,
computers
(EGSE),
that is
subsystem
to show
and electronic
including
equipment
function
flow process
This
overview
electrical
design
of the avionics
specialties.
a top-level
all vehicle
ground
between
the work/information
(Note:
but provides
design
software,
integration
function.
and
such as
engine
and the electrical
4.3.9.1
designing
Avionics
Design
the electrical
Function
and electronic
vehicle.
The
systems
and the ground
function.
Subsystems
software,
EGSE,
computer,
the engine controller(s),
receivers,
video
power
avionics
system
support
computers,
conditioners,
The avionics
design
hardware
and software
that comprise
is often considered
and checkout
of the avionics
cameras
Plane.
system
and electrical
power
systems
power. Typical
processor,
rate gyros,
includes
responsibility
the avionics
only. However,
here
multiplexers,
signal
and actuator
controls.
for the
as part of the avionics
include the vehicle
antennas,
conditioners,
The
design
instrumentation,
components
data storage,
sensors,
system
for
both the flight
DMS, RF/communications,
flight hardware
instrumentation,
distributors,
system
are included
include GN&C,
the telemetry
and processors,
to be the flight
function
transmitters,
batteries,
cabling,
design
function
avionics
plane is illustrated in figure 62. The avionics design function involves the synthesis
of the avionics system
to meet requirements
in two general categories:
(1) Performance
of the electrical /electronic
systems and
(2) resource
and interface
conditions.
The design
including
the systems
the avionics
Internal
system.
deriving
design
is responsible
the more detailed
trade studies
including
function
Reliability
system
discipline.
the requirements
for avionics
from the systems
plane and
requirements
disciplines
within
the avionics
design
systems
discipline
is responsible
(EEE)
requirements
Requirements
are considered
From these requirements,
Component
are involved
together
and redundancy
the avionics
with weight,
system
and
power, volume,
which
is a major
architecture
is defined.
definition,
but the avionics
will meet the overall
are derived
and analyses
management
in the architecture
that the architecture
and constraints
are allocated
and an electrical,
All
requirements
and
electronic,
and
parts plan is developed.
Avionics
D
Philosophy
Criteria and
Architecture
Definition
Avionics
Requirements
Constraints
and
Yes
No
Avionics
(Iterate)
Analysis and Trade
Studies
(Stop)
for
of requirements.
and integration
complexity.
electromagnetic
the requirements
categories
engineering
driver in avionics
constraints.
general
and thermal
in other design functions
system
level of redundancy
function
power use, volume,
plane is vital in determining
requirements.
for assuring
weight,
with disciplines
the aforementioned
is the avionics
for understanding
the appropriate
interactions
with the systems
plane establishes
avionics
are performed.
and cost to determine
cost, reliability,
system involves
plane. Interaction
The system
to the avionics
This discipline
requirements,
of the avionics
Informal
__.
i Integration_
Avionics
Approaches
Avionics
Performance and
Uncertainties
Avionics
Design
Attributes
Avionics
• Performance
° Power
• Cost
Component
Requirements
and Constraints
Factors
• Reliability
Factors
Resources
and
Interface
• Weight
• Volume
Accommodation
• Operability
Figure
62. Avionics
design
function
plane.
123
An important
factor
at the time of the architecture
extent
of verification
of the avionics
testbed
or hardware
simulation
are integrated
This testbed
avionics
system
software.
Flexibility
at all times.
or, in some
The
In some cases,
Within
is the determination
verification
the testbed,
vehicle
of the means
may begin
in an avionics
and engine
computer
and
systems
simulations
with the various hardware
elements
allowing
early system testing of the avionics system.
is also used for the important
function
of verification
and validation
of the vehicle flight
have to be present
software
system.
laboratory.
definition
cases,
defined
is built into the testbed
Those
simple
architecture
hardware
elements
electrical
simulations.
provides
the basis
so that all avionics
not present
hardware
are simulated
for preliminary
layouts
elements
do not
with computers
and
of the various
avionics
elements. The preliminary
layouts are determined
from the judgment
will best meet the requirements
and the proper division of hardware
of the designers
as to what hardware
and software functions.
Analysis and,
where
and uncertainties
appropriate,
breadboard
testing
determine
the performance
of the components.
Packaging
to accommodate
the environments
is designed,
and estimates
are made of the power, weight,
volume, and thermal characteristics.
The collected
attributes
of the preliminary
design are then compared
with the avionics
relief
from
requirements
requirements
individual
elements
the avionics
is sought
from
of the preliminary
subsystem.
representation
and constraints,
Testing
of the avionics
the
design.
as a system
systems
Project
and the design
is iterated
system
plane.
Make
These
elements
or buy
process
Vehicle
Integration,
decisions
are built and tested
may be done in a hardware
design
until satisfactory
and the interactions
Checkout,
are
before
simulation
convergence
made
is depicted
in figure
and Flight
63.
System
Perform
Vehicle
Avionics
System
Testing
Elements
Subsystem
or Buy
Elements and
System
Internal
Avionics
System
Engineering
and Integrtion
Test/Qualify
Design
Function
Avionics
System
Elements
;fine
Avionics
Avionics
System
Architecture
Design
System
Elements
and Development
;rmine
Thermal,
Avionics
Internal
System
Avionics
Manufacturing,
and Test Discipline. _
System Engineering
and Integration
Project
Requirements
Figure
63. Avionics
systems
design
process
into
An overall
Avionics
Management
124
on the
integrating
laboratory.
or
interactions.
Into
A listing
of inputs
ties and products
is shown
elements
that comprise
plane.
Table
chart
lists specific
outputs
tasks
nature.
I Requirements
Figure
activi-
design
considerations
for the
process
for a typical
subsystem,
avionics
in the task categories
of section
for the other subsystems,
17 are an adaptation
of the process
4.3.9.3
including
I_
I
I
I
GN&C,
Communications,
Electrical
Data
Power System,
I
Management
Software,
I
Subsystem,
• Component
• Make/Buy
Analysis
and
software,
be
would
and task WBS
• Flight Components
• Instrumentation
Evaluation
Program and
Component
List
• Design
Reviews
(IPCL)
• Verification
• Schematics
and
Specifications
and
Drawings
For:
• Ground Support
Software
Specification
• Project Design
• Parts List
• Manufacturing
• Vehicle
Configuration
and the inputs
• Flight Software
• GSE
EGSE
and
Environments
• Structural
• Materials
The WBS
Products
--i,.- I
• Aerodynamics
Induced
of the avionics
the DMS.
flow diagrams
Flow
I Con u,,a,,on
I O ,,on
I Zra Ie
I
Inputs
with discipline
with the flow diagram
The WBS
64 and table
addresses
along
and is consistent
Internal
_1
--.....
flow diagram
process
system
I
Oon ra,n I -'
• Concepts
__
process.
function
2.
k
Program/Project
for the design
design
design
64. This process
that are embedded
of the subsystem
of reference
in figure
for the avionics
the total avionics
17 is a WBS
of a similar
charts
and outputs
Reports
• Test Requirements
• Test Procedures
Structural
Design
• Performance
and
• Test Reports
Trajectories
• Interface
Control
• Mass Properties
• Thermal
• Hazard
Analysis
• FMEA
Inputs
• Guidance
Controls
• Software
Requirements
• Software
Development
• Propulsion
• Ground Operations
• Software
• Software
Design Specification
Test Procedures
• Flight Operations
• Systems
Simulation
• Safety
• Integration
and
Drawings
Inputs
and Test Plan
Testing
and Verification
Test Support
• Reliability
• Cost
_
I
Hazards
Benefits
I I Cost/Make
IiI or Buy
I
Resources
.Utilization
Figure
Reliability
I
Operability
I
Maintainability
I Requirements
I Test Req'ts/I
I Feedback
I Procedures
64. Avionics
process
S_V
I Algorithms
flow diagram.
125
Table
17. Data management
subsystem
Inputs
Tasks
Outpuls
• Avionics system requirements
• Avionics architecture
• IP&CL
• Natural and induced environments
- Thermal
- Vibration
- Radiation
- EMI
• Materials
3.10.3.1
• Weight
• Power
• Volume
• COSt
• Verification requirements
• Manufacturing
• Vehicle configuration
• Flight operations
• Ground operations
• Safety
• Reliability
3.10.3.3.1
Parts list
3.10.3,3.2
Schematics
Components
3.10.3.1.2
Avionics system inputs
3.10.3.2
Design
3.10.3.2.1
Trades and analysis
3,10.3.2.2
Subsystem design
3.10.3.2.3
Documentation
3,10.3.3.3
Released drawings
3,10.3.4
Test
3.10.3.4.1
Test requirements
3.10.3.4.2
Test procedures
3,10.3.4.3
Component tests
3.10.3.4.4
Subsystem tests
3.10.3.4.5
3.10.3.5
and development
design
interactions
of the other
examples
function
Test reports
Subsystem/component GSE
3.10,3.5,1
GSEtrades and analysis
3.10.3.5.2
GSEdesign
3,t0.3.5.3
GSEtest
of typical
functions
GSEdocumentation
Project/program reviews
of the avionics
from the onset.
design
- Data processors
- Remote data acquisition units
- Storage devices
• GSE specifications
- Subsystem design
- Components
• Released drawings
- Test specifications and
procedures
Components
3.10,3.3
3.10.3.6
the avionics
• Subsystem design specifications
• Flight components specifications
- Computer
- Command receivers
Requirements
3.10.3,1,1
3.10,3.5.4
The design
task description.
software
and the EGSE
The development
functions
through
relegated
to the software,
should
of the software
the systems
plane.
such
This is evident
as execution
be an integral
requirements
part of
requires
the
from consideration
of
of vehicle
and engine
control
algorithms,
receipt, interpretation,
and execution
initiation
of uplinked
commands,
acquisition
from on-board
instrumentation,
and compilation
and formatting
of instrumentation
and operations
of data
data for
telemetry
lag
downlink.
development
requirements.
requirements
to coincide
requirements
of the system
system
must
and analog
and monitor
for the completion
design
a process
similar
interfaces
and the telemetry
GSE requirements
ground
hardware
aforementioned
instrumentation
processing
simulation
functions.
laboratory,
for the vehicle
for ground
checkout
to the flight
for meeting
power
process.
system
particularly
systems
The design
design
requirements
data and the vehicle
computer must be developed.
In some
some software
design
commonality
hardware
may
it may be prudent
there may be requirements
and acquiring
requirements
of the preliminary
on the overall
the vehicle
software
For example,
and require
voltages
of the detailed
with the review
have numerous
system for the EGSE
desirable
to achieve
126
depend
plane. Typically,
to control
may be complex
system
the development
of the hardware
of the software
The EGSE
Typically,
process.
system.
is a responsibility
and a ground
of these
EGSE
The ground
for issuing
telemetry
and review
of the avionics
which
the
command
stream.
A user
computer
systems
computer
discrete
interface
cases, it may be cost effective and technically
in the EGSE computer
system
and the
in the user interface,
the command
handling,
4.3.9.2
Inputs
Avionics
to the process
Gates.
Decision
are the avionics
gates
for the avionics
philosophy
and approach,
design
process
the environments
performance
requirements
from the vehicle subsystems
that require avionics,
thermal, and structures.
Interactions
with these subsystem
design functions
design process.
which measure
gates which
measure
and (3) resource/operational
for the hardware,
conditioning
the ability
gates which
requirements,
of the avionics
measure
reliability,
attributes
hardware
to withstand
such as weight,
operability,
power
and cost. Functional
consumption,
performance
packaging
design
Avionics
program
requirements
and operability
manufactured,
and
its environments;
testing. Layout
are environmentally
the
65.
such as GN&C, propulsion,
are required
throughout
the
by analysis,
simulation,
and breadboard,
prototype,
and qualification
withstand
thermal and vibroacoustic
environments
lead to units which
gates,
in figure
Gates for the avionics
system fall into three general categories:
(1) Performance
gates
the functional
performance
of the various avionics subsystems
against their requirements;
(2) survivability
thermal
are shown
being
modified
and resources.
are measured
avionics
until
system
and avionics
survivability
The top-level
against
allocated
drawings
is demonstrated.
attributes
such as cost, weight,
requirements.
Once the design
and specifications
components
can be released,
and subsystems
and packaging
to
tested, with the
designers
power,
are guided
volume,
has converged
software
volume,
is determined
reliability,
to satisfy
produced,
by
all
hardware
tested.
Yes
)_
Reliability
I_
', No
Avionics
System
Drawings
and
Specifications
• Flight Hardware
• Flight Software
• EGSE
Performance
of System,
Yes
Components
_,
Subsystems,
Requirements
Avionics
Design,
Meet
Analysis,
and Test
and
• Breadboard
• Prototype
I
• Qualification
I
Withstand
I
, No
Components
Environment
• EMI/Radiation
• Packaging
• Thermal
"_--.
No
Ye,,_
:
Vibro-acoustics
, No
Avionics Requirements
and Constraints
I
I
Avionics
Philosophy/
I
Approach
Environments
Operability
Figure
65. Avionics
system
design
function
gates.
127
4.3.9.3
described
Avionics
below.
The
Tasks.
design
The
Table
include
128
18. Primary
both
tasks
design
activities
are summarized
and
ground
support
for avionics
design
function.
flight
in table
18 and
Tasks
1. Requirements
determination and
allocation
System
Internal system groups
Control
G&N
Propulsion
Thermal
Natural environments
1. Consult with system to aid in initial requirements allocation of
cost, reliability operability, maintainability, etc.
2. Consult with control, G&N, propulsion, and any internal system
group to obtain avionics hardware/software/EGSEperformance
requirements.
3. Obtain environmental requirements, both natural and induced.
4. Feedback attributes to system and to system groups. Provide
trade data and consultation for revised allocation, if required.
2. Avionics architecture
System
Internal system groups
Control
G&N
Propulsion
1. Obtain requirements from system and other system groups that
specify hardware/software requirements.
2. Identify candidate architectures and component options for flight
and ground.
3. Determine redundancy concept.
4. Identify initial make/buy approach.
5. Perform initial top-level assessment of attributes and compare
with requirements.
6. Modify architecture as required and iterate requirements if needed
to achieveconvergence of attributes and requirements.
'3. Avfonics subsystem
design
tntemalsystem groups
Control
G&N
Propulsion
Thermal
Structures
Environments
l. During detai{ed design, maintain close coordination with system
groups that specify hardware/software requirements.
2.For subsystems, including EGSE,and components that are to be
made versus bought, perform necessary design steps through
concept identification, analysis, breadboarding, component
testing, and integrated testing.
3. Developnecessary software from requirements through coding,
checkout,and verification and validation testing.
4. Iterate performance and requirements to obtain convergence.
5. Track cost, reliability, operability, and maintainability attributes,
iterating with system if not compliant with requirements.
4. Verification
Internal system groups 1. Establisha verification plan at early stage of design or
Control
procurement.
G&N
2. Perform functional verification incrementally as components are
Propulsion
developed.
Thermal
3. Perform qualification testing on flight components.
Structures
4. Perform integrated testing of hardware components on integrated
Environments
test beds.
5. Perform verification in applied environments--vibrations,
thermal, vacuum, EMI, radiation, etc.
Task
1--Requirements
system
design
where
avionics
all of the avionics
function
has
Determination
and the avionics
responsibility
subsystems
and other
for
and Allocation.
design
function,
hardware/software
appropriate
interacting
This
working
are
equipment.
interactions
the
subsystems
avionics
include
Activities
4.3.9.3.1
between
top-level
activities
activity
also
design
disciplines.
and
is a joint
with
responsibility
the design
functions/
implementation.
These
As the hardware/software
design
organization,
maintainability,
avionics
components
responsibility
accelerometers,
from
the avionics
power
usage,
the control
are derived
design
through
function
components
propulsion
design
in determining
the appropriate
Avionics
radiation,
consults
flow from the respective
vibroacoustics,
materials
selection.
the
system
organizations
with the interfacing
Avionics
directed
toward
meeting
with component
factor
in the architecture.
made,
comparing
requirements.
Significant
with the system
4.3.9.3.3
Task 3
is of an iterative
with the systems
design
functions
margins,
detail
iterating
their designs
from experience
Avionics
Subsystem
When
proceeds
ponent
testing,
Verification
test,
function
The software
design
detailed
design
may not reach
and scheduling
for functionality,
process
The
performance,
avionics
is maintained
groups
by detailed
is to make
a similar
detailed
process
primarily
specification
design
design,
com-
as the hardware.
during
as soon as the hardware
the avionics
design.
This
development.
and the inte_ated
with the environment
and EGSE
are also
a component,
are derived
of the vehicle
and compatibility
subsystem
of margins,
breadboarding,
maturity
is
iterations.
requirements
components
as the flight components
compliance
avionics
the systems
is replaced
goes through
in the planning
Task 4----Verification.
is an iterative
design,
is
on requirements
reasonable
Management
the decision
of the software
the software
Since
requirement
preliminary
assessment
subsystems.
refines.
When
some
as a factor
When
is a major
etc., with their
and detail. Close coordination
the design
testing.
process,
iterations
necessitate
may change.
and integrated
because
may
at this stage.
role in minimizing
analysis,
operability,
fidelity
requirements,
which
and a top-level
As with other parts of the vehicle,
requirements
and verification.
simulation,
options,
on the avionics
stated,
design
must be verified
fidelity,
philosophy
for redundancy
cost, reliability,
definition
is to buy a component,
concept,
must be recognized
4.3.9.3.4
Design.
steps of greater
an important
procurement,
As previously
hardware
to greater
the decision
through
entailing
begins
as the hardware/software
base, plays
development,
to make/buy
and disciplines
design
and
and component
and failure
requirements
iteration
architectures
reliability
in meeting
entails
to all parties.
and interaction
drive the requirement
difficulty
subsystem.
allocation
Vehicle
is given
which
requirements
the requirements.
of performance,
nature,
groups
usually
candidate
consideration
for cost,
requirements
acceptable
identifies
estimates,
requirements
performance
to a design
and
induced
with materials
for that particular
avionics
attributes
and other
interacts
and
responsibility
on initial
system
with satisfactory
Avionics
are derived
to the
the avionics
the natural
subsystems,
reliability
Initial
estimated
Based
rate gyros,
are obtained
instrumentation
between
of top-level
design
to converge
from
requirements
to converge
Architecture.
with the system groups for the avionics
in conjunction
groups
interaction
allocation
performance
with satisfactory
requirement
by avionics
Task 2
in the
and GN&C
obtained
for the
that have the system
for propulsion
and temperature.
allocation
the top-level
avionics
are
reliability,
system
sensors
(i.e.,
and noise requirements
after intensive
have system design
feedback
functions
requirements
which
Meeting
4.3.9.3.2
plane
Performance
for control
bandwidth,
requirements
Most component
for cost,
requirements
between
from propulsion
shock,
with
and maintainability.
of the requirements
plane.
with the design
performance
Environmental
_oups:
design
the system
interaction
Similarly,
are obtained
functions.
environments
achieved
is the keeper
from
interaction
after close
set of requirements.
and avionics
options
function
in their respective
areas. For example,
etc.), the sensor range, sensitivity, resolution,
most appropriate
reliability,
design
etc., as allocated
are developed
avionics
subsystem
it will experience.
or procured,
making
129
useof testbedsappropriateto the componentor subsystembeingtested.Functionand performanceare
checkedfor the hardwareelementsover the rangeof variability that is expectedto be encountered.
Verificationof thecapabilityof the hardwareto withstandits expectedenvironmentsis accomplishedby
determiningcorrect functioningbefore,during, and after testingin the pertinent environments EMI,
radiation,vibration, acoustics,thermal,andvacuum.Softwareis subjectedto development,verification,
andvalidationtesting,exercisingthesoftwarewith asmanycombinationsof inputsandoperatingconditions
aspossible.Dependingon factorssuchasreliability requirementsandcost,it maybe desirableto subject
the softwareto independentverification andvalidation testing;i.e., performedby thoseother than the
developingorganizationsandpersonnel.Integratedtestingof the avionicssubsystemis accomplishedon
testbedsthatcombineflight-typeavionicscomponents
with simulatedor realinterfacinghardwareelements.
Thesetestbedsmay bealsousedfor softwaretestingwith boththe simulatedandrealhardwareelements.
Finalvalidation for bothhardwareandsoftwareis accomplishedin flight testing.
4.3.9.4
Avionics
Implementation
Function.
The
specifications
and drawings
required
for fabricating
The avionics
implementation
function
produces
and drawings
are developed
in the design
function
based
Depending
on these
decisions,
the philosophy
which
The
and approach.
may need to be initiated
most
common
implementation
For each
tester
examples
of the long-lead
subsystems,
such
as the flight
a stand-alone
simulation
The
may be made
the subsystem.
decision
emulates the flight subsystem
in "form,
as well as for some other subsystems,
avionics
subsystems
components
may be used
of the simulation
may be built which contain
are used in the environmental
model
may
avionics
system
fabrication
the flight
design
In the
design
there
architecture
decisions,
may be long-lead
function
or, in some
cases,
reliability
class
a unit tester
an engineering
is designed
parts.
and built.
for some
In
in the laboratory.
to test the basic
model
items
prior to the end.
of EEE
may be built and tested
with the ability
as well as
procurement
The
unit
functionality
of
subsystems
which
fit, and function." The unit tester for the flight computer
subsystem,
is useful for early software
testing. Engineering
models of the
testing
of the design
that are used for avionics
but are also the primary
system
and software
testing.
avionics
Qualification
identical parts and packaging
as the flight system. The qualification
and vibroacoustic
testing phase. For one-time flights, the qualification
unit which
to be flown
of the flight
the software.
specifications
system
to build
the
The hardware
on the overall
subsystem,
provides
and generating
are the highest
of all interfaces
function
hardware
items
computer
design
and software.
a breadboard
for subsystem
laboratory
models
models
become
the avionics
the hardware
soon after the end of the design
of the electronic
subsystem,
provides
avionics
is commonly
multiple
times,
called
protoflight
the qualification
hardware.
model
becomes
For a flight
vehicle
the basis
for the
systems.
function
phase
of the software,
design
specifications
are produced.
The
design
specifications
contain
of the architecture
information such as the overall architecture
and design of the software,
a breakdown
into individual
software
modules,
the detailed
software-to-software
and
software-to-hardware
interface
definition
of the methodology
implementation
Appropriate
phase,
groups
definitions,
the individual
of modules
the structure
for implementation
software
modules
are coded
are integrated
and tested.
Timing
implementation
of the design
requirements
are met in the software
implementation
is complete,
the
are integrated
begin.
130
software
of the telemetry
of the real-time
will
modules
meet
the
performance
interfaces,
and the
requirements
of the software.
In the
and subjected
to development
testing.
analyses
and command
are conducted
requirements.
is of critical
Ensuring
importance.
and the verification
and
to ensure
that
that the
the real-time
Once
development
validation
testing
testing
phase
can
4.3.10
Materials
and Manufacturing
The design
properties
of a material
both in the primary
production
and secondary
shaping
have been
historically
of materials
been
and manufacturing
magnified
by the rapid expansion
Composite
of advanced
require
materials,
structural
material
the development
most metal
available
Functions
system
linked.
in the development
systems
that challenge
properties
the design
on the manufacturing
and assembly
metallic,
where
Overview
are contingent
including
of design
alloy systems
etc.) are readily
structural
Design
Their
and apply, independent
to individual
necessary
to develop
with
the component
desig-n.
The
is a "best
fit" compromise
cost,
and schedule.
Assembly
special
processes,
attention
forms
thereof,
shapes.
such systems
This differs
plate,
working
the manufacturing
between
are examples
Many
(i.e., sheet,
shape. When
era has
and new processes.
methodology.
component
of final component
it is often
also require
functions
in the modem
for basic product
systems,
material,
the design
interdependence
design
material
result
phase. Accordingly,
and combinations
traditional
specific
employed,
of both new materials
nonmetallic,
properties
processes
with advanced
processes
concurrent
part configuration,
such
as welding
and bonding
which
and clearly
delineate
the synergistic
relationship
alter
from
extrusions
weight,
the properties
of a
between
materials
process
in itself,
and manufacturing.
Note:
Executing
the materials
involving
numerous
disciplines
provides
a top-level
overview
and manufacturing
and specialties.
to show
design
This document
its relationship
functions
is a complex
does not describe
and interaction
the process
with the total vehicle
in detail
design
but
process.
131
Materials
System
Aerodynamics
Trajectory/G&N
Control
Structures
Thermal
Propulsion
Avionics
Materials
Manufacturing
Other
Figure
4.3.11
Materials
Design
Materials
is considered
discipline
functions
structures,
throughout
through
the
information
132
evolving
across
function
and
process
technical
integration--materials
design
function.
Function
are
propulsion,
analysts
design
66. Design
a unique
less
rigid
in the
and
avionics.
function.
However,
the distinctions
materials
plane
in the more
between
functions
design
planes
and
such
interact
directly
with
hardware
test,
and
verification
phases.
This
interaction
is enhanced
integrated
engineering
environment
which
facilitates
the
immediate
exchange
The relationship
between
planes
and
other
design
functions
between
discipline
is shown
specialists.
in figure
66.
designers
as
development,
design
specialists
design
traditional
design,
the
Materials
than
and
the materials
of
4.3.11.1
figure
67. The
element,
Materials
output
Design
Function
of this plane
subsystem,
Plane.
is the materials
The
design
materials
with
design
all its inherent
function
plane
characteristics
is depicted
in
for a component,
or system.
: Informal -_!ntegratio_
atera
H
Requirements
and Constraints
H
Material
Candidates
Philosophy, Criteria,
Material,
and Approaches
_
Material Parameter Matrix
and Uncertainties
and Analysis
I Material
Testing
Yes
No
(Sto___(._rate)
Material
Selection
l
!
!
Failure
Analysis
Material Attributes
• Mechanical Properties
• Physical Properties
• Processing Complexity
• Failure Modes
• Cost & Schedule
• Environmental Effects
•TRL
t
Control
Material
Figure
The
material
materials
selection,
compliment
with
retirement
Unlike
not directly
The
computer
design
conventional
is being
developed.
aerospace
accessed
required,
parts
function
viewed
the
function
plane.
simplistically
as having
performance.
materials
are
visualization
This
exposed,
of a design
Rather
that
becomes
overall
responsibility
responsibility
starting
is associated
with
Data
bases,
incorporating
along
with
and analytical
the evolving
and approve
structural,
the material
function,
it provides
a part
materials
by the design
to review
be
material
configuration.
piece
desi_
function
data where
to which
materials
all conventional
and
design
Suppliers
Certified
with
their
for
extends
to the
full
receipt
and
ending
function
does
service.
a component
commercial
Materials
can
control,
from
the more
define
and
(hardware)
function
material
of environments
their
materials
design
67.
_ Fabricators
Certified [_____
I__
iJ
V
of the
all other
acceptance
the materials
data
release
documentation.
design
and
design
design
functions
specifications
in which
the mechanical
and physical
criteria
use,
for their
regarding
a physical
properties
are maintained
product
of virtually
and
can be
specialists.
Additionally,
it is the responsibility
of the materials
thermal,
propulsion,
and
develop
selections
and specifications
avionics
designs,
contained
in the release
further
drawings.
133
Material
specialists
the producibility
with their projected
design
features
The
materials
costs and development
specialists
assessing
WBS
also participate
elements
function.
of the associated
inputs
with process
and manufacturing
long lead procurements
schedules.
with resource
material
design
and table
directly
They also identify
can be reconciled
Material
and systems,
interact
of the design.
This becomes
and schedule
in acceptance
performance,
engineers
to collectively
assess
and enabling
technologies,
along
input to the other design
allocations
at the systems
and verification
and providing
structural
testing
failure
of component
analysis
2.9, and tasks
of reference
2 provide
The NxN diagram
of reference
2 (app. A) is representative
and
outputs.
The
materials
WBS
listings
elements
planes
when
of inputs
of further
herein
for the
delineation
as figure
68
19.
I Requirements
• Program/Project
• Concepts
• Design
Internal Row
I
I
Consultation
"_1
• Constraints
I
--
I
Options
Trades
Analysis
I
Cost
i
Materials and Process Design
• Compare Materials to MIL-HDBK-5
• Evaluate Materials for
I Inputs (One Way)
• Flight Operation S]l
I_
Outputs (One Way)
k
I
• Communications
and Data Handling
• Electrical Power
|
I
- Toughness, Compatibility, Life Age, Corrosion,
Toxicity, Flammability, Reactivity, Etc.
• Fabrication/Jointing Effect
• NDE Techniques
• Static and Fatigue Test/Requirements
• Contamination Analysis
• Cleanliness Evaluation
• Critical Processes Evaluation
I
'
• Storage and Shelf Life Evaluation
• Select Materials and Processes
• Ground Operations
_
II,I!
• Quality of Weld/Braze Process
• Development Contamination/Cleanliness
• Natural Environments_._pJ
I
I
I
Analysis Data
• Material Usage
Agreements
(MUA's)
• Material
Identification
and Usage List
(MIU)
• Process
Specifications
• Repair
Techniques
• NDE Plan/Data
Control Plans
I
Inputs/Outputs
(Two Way)
• Aerodynamics
and Induced
Environments
• Structural
Products
Fracture
Mechanics
Evaluation
Material
Selection
Options
• Establish/
Select Fab
Techniques
• Structural
I
for Drawing Input
• Contamination/
Cleanliness
Plans
Analysis
• Vehicle
Hazards
Benefits
Reliability
Operability
Cost/Make
Design
• Thermal
or buy
Resources
Utilization
Requirements]
Feedback
Test
Requirements
• Propulsion
• Mass Properties
• Manufacturing
• Safety
• Cost
Materials/
Parts List
Technical
Descriptions
Configuration
and Structural
Sizing/
Configurations
Maintainability
S/W
Algorithms
Server
Needs
Conceptual
Sketches/Layouts
• Reliability
Figure
134
hardware
required.
and outputs
are reproduced
where
level.
68. WBS
2.9_materials
and processes
design
process
flow diagram.
2
Table
19. WBS
2.9--Materials
design
task description.
Tasks
Inputs
• Drawings
• Componentfunction
• Load/life requirements
• Environment
- Temperature
- Humidity
- Pressure
• Accessibility
• Designengineering
and strength
requirements
• Specialmaterial
requirements
•MIUL
• Assemblyoperations
• Environmentrestrictions
3.8.1
Comparecandidatematerialsto
MIL-HDBK-5 data
3.8.2
Evaluatematerialsper MSFCSTD-506and NHB8060
requirements:
Including but not limited to:
- Toughness
- Compatibilitywith intendeduse
environments
- Life and aging
- Corrosion,stresscorrosion
- Toxicity
- Flammability
- Reactivity
- Flawenvironmentaland cyclic
growth rates
3.8.3
Evaluatefabricationand joining effects
3.8.4
DevelopNDEtechniques
3.8.5
Conductstatic and fatigue tests to
obtainmissing and neededdata
3.8.6
Contaminationanalysis
3.8.7
Cleanlinessevaluation
3.8.8
Criticalprocessesevaluation
3.8.9
Storageand shelf life evaluation
3.8.10 Selectmaterialsand processes
3.8.11 Qualificationof weld and braze
specimens
DevelopNDEtechniques
Developcontaminationand cleanliness
control plans
2
Outputs
• Fracturemechanics
evaluation
• Materialselectionoptions
• Establishmentand selection
of fabricationtechniques
• Datafor structural
analysis
• MUA
• Materialsselectionand
control plan
• MIUL- final
• Processspecifications
• NDEinspectionand
implementation
• Procedures
• Repairtechniques
• Hazardousoperations
evaluation
• Processschedules
• Personnelcertification
requirements
• NDEplan and datafor
drawinginput
• Contaminationand
cleanlinessplans
Tools:
• NASAand MIL databases
Key:
•
ELY,RLV,and RBCC
RLVand RBCC
RBCConly
135
shown
4.3.11.2
Materials
Design
Function
in figure
69. They are (I) performance,
Gates.
Decision
gates
(2) environmental
for the materials
compliance,
design
function
are
(3) producibility/availability,
and (4) cost/schedule.
'_i
Performance
I:
: NO
X
..................
.-._N I Selection
andControlPlan
.
__
"'___
J.._._
_
,___"
" I Analysi._
Failure
/
-
y
Availability
I
I
',No
...................
/
/
I
I
I
"\
__
s
--
\
7
i
DesignData
[
/
N__
• Environments
Y;_
_
/
\
..
Xl_rop;rties
_'_
DesLignd_equirements
I
I_
/
\.
_k
X
As_;_! snt
./
Environmental_
I
I Compliance
/ '
, , Compat_ity
_._'"
y
/'_F-.
"
_
....... NO,....
/
"s;.n
• ServiceLife
ProgramRequirements-- _
................
I
_J
_
..
_
",No
"'"
• Cost
• Schedule
ICost and Schedule
Figure
Functional
and service/cycle
performance
69. Materials
is determined
life. Environmental
compliance
design
function
gates.
by test, considering
applied
requires
researching
a thorough
loads,
service
environments,
of applicable
Occupational
Safety and Health Administration
(OSHA)/Environmental
Protection
Agency (EPA) regulations
regarding
the control of hazardous
materials.
This extends to the production
and use of a material or component
and
the operation
of a device
that produces
potential
suppliers
to determine
provided.
Special
purpose
certification.
consistent
for example,
However,
overall
136
This assures
properties.
hazardous
that all materials
materials
not readily
that the production
Certification
in most aerospace
applications,
and, generally,
products.
or elements
available
processes
is also required
that can effect the properties
cost of the system
waste
of component
are adequately
structure.
material
do not influence
controlled
secondary
costs
involves
design
on the commercial
for critical
of the assembled
the basic
Producibility
are available
market
may require
to provide
processes,
welding
Cost and schedule
are relatively
the design.
interaction
minor
with
or can be
vendor
a product
with
and bonding
are self-explanatory.
contributors
to the
4.3.11.3
consist
Material
of (1) requirements
development,
(4) materials
Tasks.
The
top-level
determination
and
testing
Table
Activities
tasks
allocation,
and analysis,
20.
Primary
Interactions
of the
and
tasks
materials
plane
are shown
(2) material
selection
and
(5) failure
for materials
in table
control,
20.
They
(3) material
analysis.
design
function.
Tasks
1. Requirements
determination
andallocation
System
Structures
Thermal
Propulsion
Manufacturing
1. Meetwith system anddesignfunctions to identify
initial requirementsfor materialselectionor development.
2. Consult with system anddesignfunctions to establish
safetyfactors andacceptablelevelsof risk to be reflected
in the materialsphilosophyand criteria.
3. Consult with manufacturingto confirm the adequacyof
existing methods of fabrication or to determinethe need
for additionalprocess development.
4. Work with systemand designfunctions to establish cost
and scheduleresource allocations.
5. Work with systemand designfunctions to reconcile
nonconforming materialissues,conduct tradestudies,
and, where necessary,reviserequirementand/or
resourceallocations.
2. Materialselection
andcontrol
Structures
Thermal
Propulsion
Manufacturing
Procurement
Quality
1. Consultwith designersregardingacceptablematerial
usage.
2. Reviewand approvematerialspecifications contained
in design documentation.
3. Developand maintainmaterialdata bases.
4. Consult with manufacturingto resolve primary and
secondarymaterial processingissues.
5. Coordinatematerialsupply issueswith procurement
and quality.
6. Maintainmaterialcontrol recordsfor critical hardware.
3. Materials
development
System
Structures
Thermal
1. Consultwith design to obtain requirementsfor new
materials.
2. Consult with manufacturingregardingapplicable
Propulsion
Manufacturing
Qualify
processes.
3. Work with quality to certify new materialsand processes.
4. Materialstesting
and analysis
Structures
Thermal
Propulsion
Manufacturing
1. Consult with designers regardingadequacyof available
materialsdata.
2. Perform testing to developsupplementalor "design
specific" data.
3. Coordinatespecimenfabrication with manufacturing.
5. Failureanalysis
Structures
Thermal
Propulsion
Manufacturing
Qualify
1. Consultwith design andquality to develop failure
analysisplan.
2. Coordinatespecimenrequirementsfor simulating service
failures with design and manufacturing.
3. Work across disciplinesto implement failure analysis
plan, developfault trees, andcoordinatesupporting tests
and documentationreviews.
137
4.3.11.3.1
requirements
design
Task
1--Requirements
is determined
functions
user design
to identify
Typical requirements
service environments,
among
formal
fed back
design
imposed
requirements
function,
consults
functions
to the systems
allocations
from
gates.
and disciplines
function
4.3.11.3.2
Task 2--Materials
cannot
range
involves
an assessment
of the manufacturing
of loads
and, in some
resolve
The materials
design
design
function
an element
and their pedi_ee
quality escapes,
materials.
accessed
Materials
in concert
Development.
with the manufacturing
associated
with research
However,
it can also
be the
is not apparent.
the materials
to which
material
are determined
and informal
allocation.
based
commercial
activities
on their ability
Selection
result
Traditional
of unique
suppliers
to upgrade
unique
design
ranges
over
138
Task 4--Materials
selections
for materials
made
and supplement
applications
the full
further
by the other
control,
for all critical
data. It maintains
This data base is continually
updated
is also a primary
flight
and
a current
data
as new information
computer-equipped
location.
responsibility
of the materials
control is imposed
on all critical flight
of all materials used in these applications
Materials
development
and hardware
design
the present
aerospace
often cannot
Testing
is undertaken
functions.
Materials
for which
investing
a broader
their resources
or assist
complement
in analyzing
of standard
Materials
data base. Testing
service
assessment
or other
testing
and analysis
hardware
techniques
service
by the materials
development
state of the art for aerospace
requirements
justify
and Analysis.
the design
to
life cycle
hardware.
commercial
to produce
materials without government
subsidy and/or indemnification.
Interestingly,
in many cases, broader
evolve once these materials
are developed
and their properties
characterized.
performed
As the
is achieved.
availability,
are generally
are
in a variety of databases.
Material
specialists
or where indepth assessment
of viable material
repository
to extend
and
iteration
and sensitivities
they will be exposed.
selections
allocation.
and criteria
until convergence
are selected
from any appropriately
of configuration
Task 3--Materials
4.3.11.3.4
and the
or development.
verifiable.
Issues such as cycle-life
limits, out of specification
and fraudulent
parts drive the requirement
for material control.
is normally
market
and other
function
function,
of the requirements
iteratively
also review the final material
documentation.
aerospace
design
the attributes
to be employed,
cost. Initial
is the principal
and can be readily
control,
function
selection
revision
and Control.
processes
instances,
all-conventional
4.3.11.3.3
design
for material
the problem,
design function
with support from quality assurance.
Material
hardware and associated test facilities. It requires that the location
be traceable
environments,
function,
for the requirements
to be updated
and environments
options is warranted.
Material specialists
test hardware
and concur in the released
Material
of materials
and identifying
an appropriate
selection and control philosophy
Metrics
appropriate
design functions
using information
contained
assist in the selection when available
data is insufficient,
available
design
do not meet the requirements
and possible
Selection
in the overall
of the component,
level.
for the requirements
function
becomes
allocation
with the system
by the system
requirements
the materials
attributes
for trades
it is common
are made
the system
If the material
progresses,
base on virtually
The
the system
the initial requirements
role in defining
function defines
formally
in the decision
the design
design
Materials
and flowdown
design function
has a central
Likewise,
the materials design
included
and Allocation.
include mechanical
and physical properties,
compatibility
with other materials
and
failure-mode
constraints,
environmental-compliance
constraints,
and cost and schedule
While
that are then
by the materials
that are users of the materials.
functions
constraints.
jointly
Determination
and materials
these
markets
analysis
are
are also done to support
failures.
for determining
Testing
and analysis
the physical
and
mechanicalpropertiesof materials.It alsoincludessimulatedservicetestingin theenvironmentsuniqueto
spaceflight, suchasvariousformsof oxygenandhydrogencombinedwith highpressuresandtemperatures,
testingcorrosivemedia,andspaceradiationtesting.
Certainmaterialsarebatchsensitive;i.e.,vagariesin theproductionprocessresultin materialsthat
differ in serviceperformancefrom batch to batch. Somenonmetallic materialsused in oxygen-rich
environments,for example,mustbetestedfor impactsensitivityandindividual batchesacceptedfor use
basedon thetestresult.
Data from all testsareultimately reviewedby materialspecialistsfor significanceandaccuracy.
If it passesthesescreens,it is thensubmittedfor inclusionin the materialsdatabase.
4.3.11.3.5Task5--Failure Analysis.Assessment
of materialfailuresis performedby thematerials
designfunction.It is oftenconductedin concertwith otherdesign,analytical,andquality disciplinesthat
interactto definetheroot causeof acomponent,system,or test-facilityfailure.The actualanalysisof the
failed hardwareis precededby a plan that assuresevidenceis not lost in the handlingof the part or the
sequenceof dissection.Failure analysisemploysa wide rangeof sophisticateddiagnostictechniques. In
many instances
it requires simulating
the failure in specifically
designed
test specimens
under precisely
controlled
conditions.
A fault tree is also a common
tool used in exploring
significant
failure events. The
fault tree starts
with the resultant
are less probable
to arrive at the most probable
testing,
and detailed
documentation
and explores
all possible
cause.
contributors,
weighing
Fault trees are characteristically
and rejecting
those
that
supported
by analysis,
reviews.
139
Manufacturing
4
System
#.
Aerodynamics
Trajectory/G&N
Control
Structures
!
4
Thermal
Propulsion
4t
Avionics
Materials
_4
Manufacturing
il
Other
Figure
70. Design
process
technical
integration--manufacturing
design
function.
p
4.3.12
Manufacturing
The
Design
manufacturing
Function
design
function
includes
implementation
of the manufacturing
process.
The relationship
and other
functions
in figure
70.
design
4.3.12.1
depicted
inspection,
They
certification,
Function
of this plane
and test. Residing
activity.
and certification;
Design
71. The main output
are requirements
fabrication
140
Manufacturing
in figure
manufacturing
is shown
The
significant
determination
tool design
and assembly.
all activities
Plane.
between
The
is planning
on the manufacturing
subelements
and allocation;
and development;
with
manufacturing
plane
design
definition
function
function
plane
to specify
detail
is
fabrication,
involved
in section
and cost; process
selection
and
design
are the subelements
in limited
scheduling,
subcontractor/vendor
the
the manufacturing
and documentation
are described
planning,
associated
in the
4.3.12.3.
development
and control;
and
parts
_ Informal
_:
_- Integration
Manufacturing,
Manufacturing
Requirements
and
Constraints
Yes
l
Manufacturing
Options
Manufacturing
Parameter Matrix
and
Uncertainties
Philosophy,
Criteria, and
Approaches
Planning
and
Scheduling
No
,L
(Sto_rate)
T
Process
Development
and Certification
Manufacturing Attributes
• System Performance
-Dimensions and Tolerances
-Effects of Manufacturing on
Materials Properties
• Process Robustness
and Efficiency
• Cost
• Schedule
• Environmental Effects
• TRL
Figure
Manufacturing
requirements
of the released
design
documentation.
hardware
designers,
analysts,
the
process
material
engineers,
specialists,
interactions
project
are necessary
hardware,
and
The
react
WBS
engineers,
elements
design
delineation
of the associated
table
function
in compliance
Manufacturing
and
and contractors
with program
engineers
safety
personnel,
throughout
schedules,
determine
the
problems
that
impact
and
tasks
of reference
2 provide
listings
The
NxN
diagram
reference
2 (app.
manufacturing
WBS
outputs.
The
of
may
of
A)
cost
of discrepant
and
are
These
or schedule.
outputs
is representative
elements
interact
personnel,
cycle.
disposition
inputs
demands
planners
the manufacturing
adjust
and
and
contracting
or unforeseen
inputs
changes,
plane.
hardware
quality
Tool Design
and
Certification
redirection
2.14
function.
for producing
vendors,
to coordinate
to program
manufacturing
72 and
responsibility
design
has overall
with
as figure
71.
Manufacturing
and
Subcontractor
and Supplier
Selection F
Control
Parts
Fabrication
and Assembly
reproduced
for
of
the
further
herein
21.
141
I Requirements
h
[
• Program/Project
• Concepts
• Design
!
I.
|
I
• Constraints
I
I
Internal
Consu,to,,on
I O0,ioos
I ro0es
I Ano',sis
I Oos'
I
Manufacturing
and Assembly
Analysis
• Fabrication/Joining Techniques
• Fabrication Practices:
I¢
...........
Inputs
(One Way)
• Ground
Operations
Outputs
(One-Way)
• Communications
Flow
r
I
_
II
-Forging
-Casting
-Weldment
I
-Composite
-Adhesive
b
I
-Joining
• Material
!
I
Products
I
• Input for
Drawings,
Specifications,
Etc.
• Hardware
Control
• Manufacturing
and Control
Plan
I!
I!
I!
I!
II
II
II
II
II
• Assembly and
Verification
Plan
• Make or Buy
II
II
li
Form and Selection
and Data Handling
Inputs/Outputs
(Two-Way)
• Vehicle
Configuration
and Structural
Benefits
Reliability
Operability
Cost/Make
Resources
Utilization
Requirements
Feedback
Test
SNV
Server
Requirements
Algorithms
Needs
or Buy
Design
• Materials
I
I
• Propulsion
• Reliability
• Cost
I
Technical
Materials /
Parts List
Descriptions
Sizing/
Configurations
72. WBS
2.14--manufacturing
Table 21. WBS
Inputs
2.14--manufacturing
• Qualityplan
process
process
ELV,RLV,and RBCC
RLVand RBCC
RBCConly
flow diagram.
task description.
Developfabrication and joining techniques
Evaluatefabrication practice:
- Forging
- Casting
- Weldment
- Composite
- Adhesive
- Joining
- Etc.
Evaluatematerialform and selectionfor
best manufacturing practice
Tools:
• NASAand MIL databases
•
design
Tasks
3.14.1
• Drawings
3.14.2
• Componentfunction
• Assembly operations
• Schedules
• Inspectionand assurance
requirements
• Costrestrictions
• NDEplan
• Cleanlinessplan
3.14.3
• Contaminationplan
142
Conceptual
Sketches/Layouts
I
Figure
Key:
Maintainability
Hazards
2
2
Outputs
• Input for drawings, notes,
specifications,etc.
• Hardwarecontrol
• Manufacturing control plan
• Assemblyand verification plan
• Make or buy plan input
4.3.12.2
function
Manufacturing
are shown
(4) logistics,
Design
in figure
73. They
(5) environmental
Decision
gates for the manufacturing
(2) robustness,
(3) system
performance,
• Fabrication
i HardwareDocumentation
• Inspection
• Certification
__'°°_.
• Test
Environmental_
Compliance No :
Costand
Schedule
..No.
................
....T
Requirements
• Program
• Engineering
Performance
System
Facilities
Oesign
"
,.No...,
73. Manufacturing
early in the design
the design
process.
Manufacturing
specialists
to assure
that the component
engineers
requirements
are incorporated
within
or simplify
the manufacturing
process.
proposed
facilities,
material
times
for procurement
along
with projected
input
to the other
allocations
is generally
developed
a new process
processes.
and/or
modem
They
also reduce
allowed
systems
the need
where
inherent
These
is placed
control
and parts vendors
design
throughout
with designers,
analysts,
and material
and that appropriate
also address
to support
schedules.
level.
and continues
manufacturing
these take the form of modifications
reviews
and development
planes
Before
Often
Producibility
directly
gates.
or assembly
can be produced
for their production
design
newly
participate
the design.
function
of a component
processes
at the systems
Robustness
interaction
costs
design
or assembly
suppliers,
or new
No _,
Logistics
Figure
is addressed
',,
...........................
Yes
Producibility
design
and (6) cost and schedule.
_
"-,,
__>"_"-I
Gates.
are (1) producibility,
compliance,
ProcessRobustness
and Efficiency
_...No...............
_4--_
Function
features
the project.
are identified
The output
the availability
Items
frequently
rely heavily
into production,
formal
operating
on operator
long lead
reviews,
processes
These
promote
consistency
in the process
for highly
skilled
operators
by limiting
and controlling
becomes
and schedule
but is often lacking
a satisfactory
are developed
added.
reviews
to resource
skill to produce
procedures
of
that require
of the producibility
manufacturing
cost
in the producibility
can then be conformed
in well established
to reduce
and adequacy
in
product.
and rigid tooling
and add to its robustness.
the degree
of operator
in the process.
143
System
the
performance
requirements
tolerances,
established
material
attribute
logistics
gate
assure
safe packaging
requires
thorough
inspection
extends
of workers
on program
to its release.
of applicable
Typical
involved
with designers,
of large
and/or
in these
It is advisable
made
to allocate
of launch
Tasks.
primary
tasks
and
system
function
and other
and constraints
are then allocated
manufacturing
activities.
design
typically
and development;
and Allocation.
functions
with manufacturing.
that interact
via the system
The system
design
plane controls
function,
however,
has a central
formal
constraints,
facility
function
also identifies
which
are then formally
gates. When
discussions
between
the attributes
and sensitivities
the requirements
Task
2--Planning,
of the producibility
control
often
require
Development
and mature
them
in
and cost;
identification,
and
process
with
the
requirements
initiates
the
and constraints.
and identifying
appropriate
process
constraints,
verification,
and
cost
and
the manufacturing
philosophy
are determined
Metrics
for the requirements
support
the imposed
If the problem
cannot
design
function
for trades
and Cost.
Planning
into the detailed
instructions
are generally
adequate
that the manufacturing
of this plan parallels
any procurement
effort
tooling
and manufacturing
concepts
Scheduling,
process
organization
144
process
These
cannot
are initiated.
reviews
the quality
be developed
shown
of manufacturing
function.
attributes
Written
effort.
plan.
functions
are
in conjunction
of requirements
role in defining
critical
are fed back to the system
the manufacturing
projects
by the design
the manufacturing
the design
plane
requirements,
be resolved
and
informal
in this manner,
and possible
revision
of
allocation.
4.3.12.3.2
stages
imposed
negative
scheduling,
and this flowdown
allocation
compliance
design
function
plane
environmental
for the decision
heavy
the design
greater
The determination
include
criteria
and
(5) subcontractor/supplier
design
to manufacturing
The manufacturing
a much
by the manufacturing
and constraints
constraints.
have
(2) planning,
requirements
training,
places
to optimize
manufacturing
allocations.
schedule
development
of the
design
operator
process
is self explanatory.
and allocation;
The manufacturing
Typical
materials.
and assembly.
Determination
is achieved
vehicle
compliance
of hazardous
gate
to
in the project.
(4) tool design
and (6) parts fabrication
Task l--Requirements
design
The
determination
certification;
Environmental
time and resources
after its release
4.3.12.3
of (1) requirements
assemblies.
in the manufacturing
earlier
and constraints
and
is a key
specialists
employed
to the design
Manufacturing
and transportation
The cost and schedule
adequate
requirements
dimensions
of toxic materials
processes.
phase
development
to achieve
performance
the control
to note that the manufacturing
Changes
4.3.12.3.1
analysts,
assets.
and control;
System
regarding
made
selection
include
criteria.
delicate
than changes
(3) process
activities
regulations
on both cost and schedule
table 22. They consist
requirements
and maintenance
OSHA/EPA
to the use and disposal
It is important
impact
interaction
and transportation
the protection
functions.
criteria,
of manufacturing
function.
involves
research
This research
demands
the ability of the full complement
by the design
properties,
of the manufacturing
The
prior
reflects
having
and certified.
a major
production
also contain
to manage
philosophy
of the design
manufacturing
component.
vendor
to be employed
and supplier
control
begin
in the early
documents
that govern
the inspection
small projects.
be defined
development
processes
It describes
which
and scheduling
requirements
However,
in a comprehensive
and is normally
The manufacturing
of
large, complex
manufacturing
a data requirement
of
plan outlines
the
and identifies
any new processes
requirements,
inspection
that must
requirements,
and
Table
22.
Primary
tasks
for manufacturing
design
function.
Activities
Interactions
Tasks
1. Requirements
determination and
allocation
System
Structures
Thermal
Propulsion
Manufacturing
1. Meet with system and design functions to identify initial
requirements and constraints.
2. Consult with materials regarding unique material
processing requirements.
3. Work with system and design functions to conduct trade
studies and establish cost and schedule resource allocations.
2. Planning, scheduling
and cost
Project
System
Structures
Thermal
Propulsion
Materials
Procurement
Quality
1. Work with design, materials, quality, and procurement
to define the manufacturing approach or develop the
manufacturing plan.
2. Work with project, system and design to identify new
facility requirements.
3. Consult with project, system and design to reconcile priority,
cost, and schedule issues.
3. Process
development and
certification
Structures
Thermal
Propulsion
Materials
Procurement
Quality
1. Meet with design and materialsto establish requirements
for new manufacturing processes.
2. Work with process and material engineers to develop new
manufacturing methods.
3. Work with procurement and/or quality to certify new
manufacturing methods.
4. Tool design and
development
Project
System
Structures
Thermal
Propulsion
Procurement
Materials
Quality
1. Coordinate tooling requirements and approach with
design and materials.
2. Reconcile cost and schedule issues with project and system.
3. Work with procurement and/or design to acquire tool
documentation and hardware.
4. Coordinate tool certification with design, materials, and quality.
5. Subcontractor/
supplier selection
and control
Project
System
Design
Materials
Procurement
Quality
1. Meet with project, system, design, and materials to
reconcile unique or sole source supplier issues.
2. Work with procurement and quality to identify and certify
viable suppliers and contractors.
6. Parts fabrication
and assembly
Project
System
Structures
Thermal
Propulsion
Materials
Quality
Procurement
1. Createdetailed process specifications and work planning
documents in concert with design, materials, and quality.
2. Work with quality to train and certify technicians to perform
critical process operations.
3. Fabricateand assemble parts and coordinate changes
with design.
4. Meet with interacting disciplines to disposition discrepant
hardware, resolve problems, or react to program redirection.
145
any new facilities
needed.
The
through
flow of parts
factory
floor
selecting
layouts.
a prime
The major
tools and processes
the subassembly
The
manufacturing
contractor
for launch
unique
and inspection
plan
and
vehicle
to the project
stations
are displayed
to final
its implementation
cost
vendor
in
are major
discriminators
in
of other manufacturing
facility
determined,
and a start and
date negotiated.
Critical path scheduling
within and across projects
and aids in meeting major project milestones.
However,
changing
supplied
Controlling
results
is diagrammed
production.
Scheduling
a new manufacturing
effort cannot be done independent
commitments.
Priorities
must be established,
milestone
accomplishments
completion
of resources
items,
manufacturing
these factors
are achieved
4.3.12.3.3
requires
mistakes,
a systems
by appropriately
when manufacturing
established
standards
and
approach
scheduling
Task 3--Process
in illustrations.
assembly
design
that cuts across
reviews
Development
changes
all contribute
functions
and establishing
and Certification.
the majority
of components
for a launch
and controls. However,
achieving
higher
optimizes
priorities,
the application
late delivery of
to schedule
and disciplines.
delays.
Successful
clear lines of communication.
Traditional
processes
will be employed
vehicle. These processes
have thoroughly
performance
in a new launch vehicle may
not be possible using only traditional
occurs in select areas of the design.
processes.
Invariably,
the introduction
of new materials
or shapes
These often require that established
processes
be modified
or that
entirely
new
new material
processes
be developed
and certified.
or process
is an inexact
science
Occasionally
program
proceed
concurrent
other. An excellent
introduced
constituent
and
demands
Projecting
the time and resources
and is best accomplished
force
the development
resolution
Many
achieving
were
a coordinated
MSFC,
manufacturing
a consistent
necessary.
These
effort between
and contributing
changes
discipline
extended
specialists
contain
process
on combinations
within
them
a number
development
employs
of these critical
parameters
process is optimized,
it must be certified.
This certification
These studies establish the limits to be placed on each critical
properties
manufacturing
processes
to
area affecting
the
lithium alloy was
over
many
months
and
successful
from the material
supplier,
the external
of parameters
considered
critical
statistical
methods
for process
to
to limit the number
optimization.
Once
the
is supported
by process sensitivity
studies.
process parameter
to assure material
design
are not compromised.
4.3.12.3.4
as jigs,
Task 4--Tool
work platforms,
to hold,
manipulate,
Design
handling
or move
and Development.
slings,
parts
Tooling
transportation
throughout
tooling may support several projects,
the major
tools must be considered
during the early stages
is generally
dollies,
the various
assembly
stages
understood
fixtures,
to include
and other
of manufacturing.
such
similar
While
some
tools for a new program
are configuration
unique. These
of the program
since long lead times are required for their
and construction.
Tooling
production
146
of secondary
a
consultants.
processes
result. Modem
of tests that are required
design
specialists.
with development
of the new material
itself, with changes
in one
example of this is in the space shuttle external tank. A new aluminum
processes
required
tank contractor,
devices
to perfect
to improve performance.
Attempts
to weld this new alloy identified
an extreme
sensitivity
to
levels and other parameters
employed
in its production.
Major modifications
to both the alloy
the welding
items
required
by a team of discipline
represents
schedules
a major program
and product
quality.
cost
A careful
element
balance
and can be a significant
factor
must
the use of "hard"
be struck
between
affecting
both
and
"soft" tooling in the moredemandingphasesof production.Hardtooling strivesto maximizerigidity and
maintainthedesiredspatialrelationshipbetweenpart andprocessequipmentthroughouteachoperation.
Hard tooling is more expensiveto employ and takeslongerto designandfabricate.However,its more
precisefeaturesreducethe risk of failure andwork aroundsduring startup.Also, the useof hardtooling
generallyresultsin fewer processdefectsandfasterturn aroundtimes.Soft tooling strivesto achievethe
sameresultashardtooling but is generallylessrigid, with fewer automatedfeaturesor assemblyaids.
Advancementsin multipurposeprocesssystemsemployingrobots, sensors,andpart positioners
linked by a computerare reducingthe performancegapbetweenhardandsoft tooling. However,most
largemanufacturingeffortsstill employa mix of hardandsoft tooling, with theselectionfor eachprocess
drivenby controlrequirements,
schedules,
andotherbudgetedresources.
Designengineers,analysts,process
engineers,andmanufacturingspecialistsmustwork collectivelyto definetheappropriatetoolingapproach
bestsuitedto the programconstraintsof costandschedule.
4.3.12.3.5 Task 5--Subcontractor/Supplier Selection and Control. Small projects often are
accomplishedat onelocation without subcontractsupportandwith supplierparticipationlimited to the
provisioningof rawmaterialsor commercialpieceparts.Asprojectsgrowin scopeandcomplexity,reliance
on subcontractorsand outsidesuppliersincreases.Four commonfactorsinfluencethe decisionto use
outsidecontractors.Theseare(1) the capacityof the principalfabricatorto absorbthework involvedin the
newproject,(2) the relativecostof doing thework in-houseversusby contract,(3) thecapabilityof the
principalfabricatorto performarequiredfunction,and(4) governmentregulationsrequiringthatportions
of thework becontractedout.
Subcontractorandsupplierselectionsarecritical toprogramsuccess.
Their performanceaffectsthe
cost,schedule,andquality of thedelivereditems.Specialistsin manufacturing,materials,quality control,
andprocurementmustwork togetherto certify thateachnewsubcontractoror materialsupplierhasthe
capabilityandcontrolsto producean acceptableproduct.The processof certification hasbeengreatly
enhancedin recentyearsby the wide spreadacceptanceof criteriaemanatingfrom the ISO.Contractors
with ISO certificationhavedemonstratedthattheyhavein-placea documentedsetof proceduresthatare
adequateto control all facetsof the work they perform, aswell as satisfactorytraining of the personnel
employing theseprocedures.Maintaining certification requiresregular audit and approvalby trained
representatives
of ISO.
Specialattentionmustbegivento solesourcesuppliers.Everyeffort shouldbemadein thedesign
andmaterialselectionphaseof theprojectto circumventtheiruse.Solesourcesuppliersproducea product
thatis uniqueor of suchlimitedmarketabilitythatcompetitiveinterestin thefield issuppressed.
Occasionally,
thecommercialoutletfor a solesourcesupplier'sproductis reducedto thepointthatcontinuedproduction
is no longereconomicallyviable.Whenthis occurs,programsthatrely onsuchmaterialsmayberequired
to subsidizethe supplierto maintainproduction,fund the acquisitionof alternatesources,or developand
qualify a replacementmaterial.Any of theseoptionscanhaveseriouscostandscheduleimpacts.
4.3.12.3.6Task6--Parts FabricationandAssembly.Thedesignof acomponentor assemblyassures
its final form in the manufacturingprocess.Manufacturingengineersandproductioncontrol specialists
definethe processes
to beusedandthe sequence
in which theyareto beperformed.Skilled tradesmenare
thenrequiredto implementeachactivity.Critical processesrequirethatoperatorsaretrainedandcertified
147
in their
use. Certifications
are time limited
critical
processes
noncritical
each
workstation
flow
of parts through
each
points
and requisite
approval
operations
computer
and many
or contained
and operators
processes
in the "shop
travelers." These
step of manufacturing.
stamps
must
These
certifying
Manufacturing
results in planning
and documenting
produces
the hardware.
definition
and hardware
flowdown
of requirements
until the final design
activities
documents
design
The
process
However,
it is customary
is repeated
until
in programs
to improve
vehicle
the life-cycle
flow process.
4.3.13
Design
having
Program
performance
paper
the manufacturing
design
implementation
flow for a new vehicle.
is generally
however,
manufacturing.
iteration
function
begins
Should
of the design
function
Requirements
production,
follows
inspection
and that the
is frequently
function
with the
not initiated
the verification
with manufacturing
between
design
requirements
step in the life-cycle
flow
for a new
of operation
exigencies
or reduce
the
used
of the manufacturing
very long periods
form.
that direct
were
is achieved
the last
at
the specified
the manufacturing
further
convergence
documents
and/or
operational
for the life-cycle
evolving
All
resident
also contain
While
Hardware
requirements,
intervals.
instructions
and materials
in the life-cycle
Verification
is considered
in abbreviated
opportunities
Other
design
Operations
albeit
plane.
is released.
all hardware
performance.
midway
at prescribed
process
as documents,
the planning
at each process station.
process,
it. Implementation
from the system
documentation
hardware
to be repeated,
resides
precede
parts
Function.
the manufacturing
Manufacturing
fail to confirm
is conducted.
Implementation
by detailed
are the planning
that the right
were performed
correctly. Although
described
generated
and displayed
on interactive
monitors
4.3.12.4
be recertified
are supported
flow process
technologies
cost are the catalysts
and
vehicle.
which
offer
for reinitiating
Functions
The design functions
delineated
in the previous sections are primary
of the launch vehicle. Through the activity of subsystem
compartmentalization,
to the design and development
all hardware
and software
products
are determined.
are defined.
There
They
are hardware
are denoted
flight
the major
and software
as auxiliary
to the successful
disciplines
Subsequently,
subsystems.
of the vehicle.
then that of the major
systems,
landing
gear,
payload
conditioning,
pyrotechnics,
auxiliary
subsystems,
the design
Functions"
plane.
Reintegration
environmental
function
the subsystems
into design
functions,
On the upper
148
left
subsystems
26. Typical
control
require
fewer
of the auxiliary
design
is critical
functions
a specific
of these auxiliary
system
design
subsystem
is represented
items.
plane
but are
subsystems
(ECLSS),
a subsystem
and
may be less, there
is influenced
crew
include
interface,
by one of these
by the "Other
Design
System
three types
and the design
to reconstitute
is an example
are not allocated
examples
and life support
GSE, etc. Whenever
2.1 illustrated
process.
of those
in figure
9 in section
reintegration
may
subsystems
or they are specialty/unique
Figure
requires
activities
auxiliary
integration,
Into the Complete
talizations
design
of these
subsystems.
could be less technical
functions
recovery
the function
vehicle
of interactions
the design
Functions"
to any of the major
the number
As a consequence,
Design
functions
In addition,
there
4.3.14
However,
Their
iterations,
as "Other
design
items that do not belong
subsystems.
may be fewer design
grouped
subsystem
of compartmentalization:
functions
into disciplines.
the total system.
subsystem
the system
tree which
Figure
Each of these compartmen-
27 provides
illustrates
into subsytems,
another
compartmentalization
view
of this
of the
vehiclehardwareandsoftwareinto smallerandsmallerentities.Eachof these
has an associated
plane contains
represent
design
function
stack,
discipline
activities.
So, the tree represents
design
function
On the lower
and discipline
left, there
subsystem
tree interfaces.
flow among
the design
the reintegration
eling
provides
process
that are inherent
and sensitivity
effects
and to assess
provide
the necessary
level of confidence
As stated,
integrating
subsystem
designs,
This finally
provided
the NxN
as discussed
flight
design
function
and the stacks
information
diagram
on the design
The models
to desensitize
adequate
of the reintegrated
which
associated
represents
An important
nonlinearities,
process.
flow
function
information
feature
that aids in
planes.
The mod-
incompatibility,
enable
and uncertainties
the analysts
to perform
any of the aforementioned
margins.
Models
hardware/software
applied
systems
with the
trade
undesirable
in this manner
along
with
a high
safety.
compartmentalizations
into
then integrating
Each
compartmentalization,
previously.
by the disciplines
in order to provide
of the three
completes
is shown
for interactions,
understanding
the disciplines
represents
that can be applied
effects
regarding
each
right
the reintegration
analyses
their
right of the figure.
subsystem
which
and disciplines,
is modeling
throughout
studies
with
On the lower
for accounting
on the upper
entities
compartmentalization.
is an IxI diagram,
functions
a means
as shown
hardware/software
the design
the subsystems
the process
functions,
requires
then
reintegration.
integrating
into the complete
of reintegrating
Reintegration
the design
begins
functions
into
system.
the subsystems
into a total system
design.
149
4.4 Design
The elements
and connections
of the design
along
with specific
tasks that are accomplished
section
will address
the time sequence
two parts:
Section
4.4.1
describes
design
and detail
design
stages.
4.4.1
Conceptual
The
Design
conceptual
hypothesizing
design
candidate
selection
ordinarily
occurs
are carried
through
preliminary
design,
manufacturing,
4.4.1.1
Importance
this is that choices
(although
essential)
a flawed
concept
starting
preliminary
design,
in the previous
design
function
of the design
4.4.2
planes.
process.
describes
section,
This
There
are
the preliminary
of the vehicle
mission
selection
design
statement
process
and
typically
is the downselection
design;
however,
and in the case of a "fly-off,"
in some
multiple
which
begins
extends
with
to the
to one concept.
Concept
cases,
multiple
concepts
are carried
through
concepts
and verification.
life-cycle
Design
and the resulting
cost is locked
made during
can have no more
design
the stages
stage and section
the given
Concept
process
of saying
part
stage.
of Conceptual
of a vehicle's
engineering
design
described
the various
that comprise
is the early
to fulfill
design
of the total design
design
stage
before
80 percent
detail
have been
on and between
of activities
the conceptual
concepts
of the preliminary
success
process
Stage
beginning
detail
Sequence
preliminary
than
a minority
concept,
1.0
The conceptual
vehicle
system.
in by the concept
can mess up a good
and selection.
Stage.
design,
effect
It has been
that is chosen
detail design,
selection
stage
estimated
life-cycle
design
is crucial
engineering
to the
that at least
(see fig. 74). Another
manufacturing,
on determining
the best detailed
The right concept
design
way
and operations
cost. While
poor
will not correct
is critical.
--
0.95
Percentof
Life-Cycle
CostDetermined
,
I
;D(1)I pD(2)I
DD(3)
M & SI/V(4)
1. ConceptualDesign
2. Preliminary
Design
3. DetailedDesign
4. Manufacturingand SystemIntegration/Verification
Figure
150
74. Representative
percentage
of system
life-cycle
cost determined
as a function
of design
stage.
A significantelementof thelife cycle cost occurs
& B activity
is known
of conceptual
to result in program
and preliminary
design
Illustrated
in this figure
in phases
A and B as percent
when
programs
expected.
underfunded
Thus, insufficient
is anecdotal
of development
efforts
cost overruns.
evidence
200.
aspect
up-front
E
_ 7 "i
E
E
.
Empirical
design
efforts
evidence
in figure
effort),
program
phase A
of the influence
75 from reference
as a function
programs.
design
will impact
of the life cycle
Inadequate
C commitment
of NASA
up-front
process
development.
is shown
over the initial phase
cost for a number
in the early design
that inadequate
costs
(i.e., not enough
Another
vehicle
cost overruns.
on final program
is the final cost as excess
are initially
in developmental
developmental
efforts
during
of cost
It can be seen
cost
overruns
life cycle
4.
that
can be
costs resulting
cost is flight
and ground
operations.
There
will also result
in increased
operations
costs.
Source: Presentation by Werner Gruhl,
Office of the Comptroller, NASAHO, 1985
_
PO
_
_----100
o
I
O
x
ul
•
--
Q
0
c
o--
u.. -20
!
m
I
--
u
15
0
i
i
30
Costsin PhasesA andB asPercentofDevelopment
Cost
The
aforementioned
conceptual
design.
Here
conceptual
design
decisions
a 10:1 leverage;
1:10. Make
detail
Figure
75. Cost overruns
implies
that we must
put sufficient
quality
is at work
the familiar
lever
have a 100:1 leverage
design
use of the leverage,
drops
in NASA
effort
and put the necessary
quality
the operations
effort
into front-end
engineering
(see fig. 76). The quality
on end-product
to 1" 1; and, during
programs.
at the front
lever
and cost; preliminary
stage,
the leverage
during
idea is that
design
has
may reverse
to
end.
151
Conceptual
Design
Preliminary
Design
Detailed
Design
Product
Attributes
100:1
10:1
1:1
Figure
4.4.1.2
Convergence
by a mission
follows
statement,
a series
discarding
of Process.
Conceptual
concluding
with
that include
generating
and
of iterations
unfavorable
76. Quality
concepts.
design
a selected
This was illustrated
describing
and evaluating
the remaining
iteration.
Thus,
an iterative
downselection
is accomplished
change
in requirements
necessitates
The process
is completed
some cases,
multiple
if no clear-cut
fly-off
4.4.1.3
illustrated
initial
is apparent
without
is used (for which
Conceptual
in figure
requirements
Design
Sequence.
77. The activity
sequence
begins
that specify
objectives
and
schedule,
and indicate
philosophy
are
identified.
Typically,
concept
iterations
proceed.
are rudimentary
guide
these
vehicle
the idea
creative
process.
Sketches
of architectural
are selected.
corresponding
as a function
At this point,
152
strategies,
generation
sensitivity
in any doubt,
program-level
meet
etc.,
margin
etc. In addition,
that may
criteria
leave
an informal
the concept
Concept
a mission
program
of dry weight
screening
designers
the requirements.
evaluation
to top-level
criteria
options
may be included
in!). The remaining
concepts
and
and
safety,
strategy
and
and
refined
as the
which
initially
generators
decomposition
to these
the attributes
Other
statement
is
mature.
idea
put form
or if a
process
reliability,
and philosophy
Functional
will include
requirements.
may eliminate
are expanded
as the concepts
or in
forward
design
design
any TRL constraints,
and expanded
A
resources).
of the conceptual
strategy
design,
concepts
in preliminary
development
requirements
iteration.
in light of the revision.
cost,
program
penetration
into preliminary
providing
and
successive
at each
to carry multiple
entailed
with the program
options
reliability,
concepts
to carry forward
An overview
system
evaluation
with increased
may be refined
for performance,
the initial
and
concepts,
might choose
This is even more true of the program
requirements
13. Each
It
than for the previous
constraints
and high level and are modified
Given
candidate
detail
must have sufficient
Activity
and
in figure
to the level of detail
the program
operability,
section
discarded
initiated
design.
the concepts,
in greater
to fewer
A program
going
evaluating
and requirements
of a single concept
to carry forward.
process,
into preliminary
concepts,
concepts
a look at new and previously
upon selection
concepts
winner
philosophy
may be introduced
are a converging
to proceed
in a previous
entails
New concepts
and selection
concept
hypothesized
iteration
on each iteration.
lever.
measures
ideas,
conceive
to
and concept
of performance,
such
of
is used
cost,
as dry
weight
not competitive
(but if
as appropriate.
concepts
that are clearly
are then subjected
to quantitative
evaluation.
Inputs
Mission
Requirements
Concept
and Design
Initial
-._
Aerodynamics
I
Initial
Philosophy
Subsystem
Concept
Propulsion
i._............ _
-._
Ideas
_
/
_
Characteristics i
" - Structures
Assessment
ip_
- Propulsion
- Thermal
Outputs
Weight
l/
-GN&C
- Avionics
Sized
Configuration
Estimates
I"
- Operations
- Other
Concept Layout
and Attributes
m
j,
/
I
,%
Margins
Iterations
Technology
Maturation
Trajectory
I Performance/
Assessment
Configuration
Layout
Requirements
c°nc
I '
Propellan
Volume
Risk
Assessment
Potential Iterated
Requirements and
CbncePfidea_s....
Sizing
..........
| ......
I
!
Figure
Each
competing
In this
report,
the
level
system
variables
subsystem
at the
basic
aerodynamics
used
in
an
initial
adjusted
the
propulsion
cally
each
consists
experienced
of
the
detailed
analyses
preliminary
level
sizing
an
design
idea-sketch
level
set
the
of
characteristics
to
of
estimates.
weight
the
sequence.
is set
free
be
started
(thrust,
Isp),
and
weights.
which
then
feeds
configuration
set
vehicle/
change,
or
may
initial
estimates
initial
of
sizing
subsystems
in the
continues
be
estimates
volume
includes
to updates
process
top-
of
These
that
program.
manipulate
a propellant
leads
iterative
to
with
layout
subsystems
that
a consistent
is
This
in a sizing
to
may
adjusted
up
programs
converge
process
in a concept
and
and
program
sizing
assessment,
assessment
flow
interconnected
sizing
iterative
programs
are
approximate
is required
by
design
overview
of
These
detail
and
functional
until
aerody-
the
sizing
converged.
concept
of
in
propulsion
An
and
descriptors
The
is represented
volume.
specialists.
beyond
to the
Variables
characteristics,
current
of
applies
discretion.
volume
have
Since
assessment
lift),
at the
performance/trajectory
adjusted
performance
stage--sizing
subsystem
performance.
designer's
The
reflecting
program"
"rubberized"
(drag,
namics,
and
and
design
is characterized
"sizing
and
concept
adjustment.
Conceptual
concept
term
weights
fixed
are
77.
the
program
specialists
included
assessments
stage,
sizing
need
sizing
by
additional
for
fidelity
with
discipline
the
inputs,
subsystem
program.
discipline
has
significant
exceeded
simplifying
specialists.
assumptions,
provide
in the
tools
and
The
specialists.
the
this
assessment
outputs
by
a small
in
figure
and
assessment
fidelity
capability
shown
then
By
assumptions,
Initially,
may
be
the
time
of
current
augmented
the
design
sizing
an
typi-
group
77,
carried
with
reaches
programs,
of
more
the
and
153
the design
functions
are performed
tions
being
performed
latter
part of the conceptual
The
concept
outputs
layout,
priate
design
to the uncertainties
or in generation
Technologies
plan.
All
including
competing
among
the
system
concepts
concepts.
introduction
(these
ordinarily
func-
occurs
in the
concepts
may
be modified
is typical
for
concept
evaluation
Those
concepts
that remain
needed
and
in a need to iterate
readiness
The primary
levels
attributes
are determined,
of cost, operability,
and a risk assessment
for each concept
risk,
and schedule
risk,
and a potential
reflect
evaluation
cost
in a matrix
risk,
of attributes
reduces
number
the
criteria
ideas
concepts
have
by the analysis
the need
that
are used to evaluate
of competing
if additional
indicated
to reveal
results
to
appro-
are identified,
evaluation
in a direction
in addition
of margins
of technologies
frequently
technology
The concept
at this point,
Concepts
cost and -ility attributes
(5) identification
is scoped.
modes
are assessed
(2) an updated
78), (4) identification
The process
are identified,
performance
Downselection
include
configuration,
ideas.
to maturity
failure
(1) the sized
of figure
of the concept,
requirements.
of additional
include
attributes
of new concept
assessing
top-level
process
in the flow cycle
the technologies
includes
refined
design
for each concept
Top-level
by specialists
from the design
stage.
and (6) a risk assessment.
required
to bring
mitigation
performed
and sensitivities
the requirements
This
to being
of the concept
requirements,
performed.
program
represented
their maturation
etc., are estimated.
in each area. The transition
of the conceptual
attributes
and the effort
specialists
by the sizing
(3) estimates
the performance
by design
been
to modify
or refine
and
criteria
allows
for the
by the process.
process.
the
risk
and downselect
generated
and evaluation
is
system
In addition,
it
requirements
or
philosophy.
analysis
is performed,
concepts
are carried
concept
design
repeating
through
and selection
the cycle
process,
appropriate
to the fidelity
correct
for all projects,
because
simpler
vehicles
or more
performance
margin
significant
technology
using
should
for More
of the sizing
4.4.1.4
Process
interactions
For concepts
There
is not a single
technology
design
stage.
should
vehicle
More
program
as augmented
by a small number
sensitivities
and uncertainties,
is required
to achieve
are needed
are
Highly
than
their
or those
50 percent,
requiring
depending
in figure 77 represents
of discipline
and design
the
func-
close to the experience
base and have relatively
low sensi-
on the figure
is adequate
for conceptual
If there
is highly
unconventional,
or if the
the correct
which
at least 20 percent
vehicles
indicated
the
to carry
margins
have
The process
high
and
of the project.
use higher
complex
Throughout
set of margins
should
detailed
competing
sensitivity
Assessment.
represented
programs,
depend on the characteristics
advanced
and more
is made.
and
Indepth
assessment
154
selection
uncertainty
to 30 or even
very
specialists
In some
margin--up
and uncertainty,
function
final
detail,
have greater
tivity
discipline
before
to consider
definition.
in greater
is selected.
A well characterized
that are relatively
the process
testing
margins
more
counterparts.
development
situation.
tion specialists.
of the system
at the end of the conceptual
on the specific
internal
and
it is crucial
the appropriate
and those
conventional
are defined
until a final concept
manufacturing
margins
interconnected
after downselection
concept
conceptual
to provide
design.
In this case,
the increased
penetration.
a larger
design.
a more
group
are
indepth
of design
and
Figure78 illustratesthemoreindepthassessment
from a structures/thermal/flightmechanicsperspective.Therewould be similar processesfor moreindepthassessments
of the propulsionandavionics
systems.The processstartswith the conceptdefinition and outputsfrom figure 77, and proceedsas
indicatedto put more realisminto the conceptdesign.That is, iterationsaremadethroughthe indicated
disciplinesto bring the conceptto a morerefineddefinition that is consistentwith the physicalrealities
represented
by thedisciplines.
Start Process for
Configuration "n"
Initial Concept
Design
(From Figure 77)
\
'_
I-Natural
A
I Envir°nments
I
[
_.....___ced
interactions.
mined
78. Conceptual
design
pline-specific
sequence
in figure
78 is detailed
The individual
design
functions
comprising
activities
is beyond
that will be addressed
Major
a.
steps
Concept
[
]
] _-
stage--process
shown
by the persons
-_ I
Design
iterati0ns
(Structures/thermal/flight
The process
]
i I
_----1,
Figure
I Ivlal_"m
for more
indepth
mechanics
perspective.)
and complex,
involving
and disciplines
those
design
functions
the
scope
of this report;
execute
and disciplines.
however,
assessment.
many
concurrent
their respective
Detailing
there
tasks
these
activities
as best deter-
design
is an overall
and
and discipattern
and
below.
in the process
for each competing
concept
include
the following:
Put form to the concept.
• Make initial sketches
• Estimate
initial configuration
b.
Estimate
primary
propulsion
C°
Estimate
primary
aerodynamics.
parameters
system
(elements,
size, mass,
etc.)
characteristics.
• Total forces and moments
for trajectories
• Distribute
forces and moments
for loads
and control
155
d. Performbasictrajectory/performance
analysis,iteratingamongstructures(weight),propulsion,
andaerodynamicsto sizethe vehiclefor the requiredpayload.
e. Generatebaselinetrajectory and designreferencetrajectories.Include trajectory shaping
constraintsbasedon abortor recoveryrequirements.
f. Determinethecontrol systemphilosophy,logic, andarchitecture,basedon experience.
g. Determinecontrol authority, and analyzerigid body control responseto variations in key
parameters.
• Variationsin aerodynamics,
propulsion,massproperties,etc.
• Useload indicators
h. Assesskey stabilityissuesif they appearto besignificantdesigndrivers.
• Aeroelasticity,propellantsloshing,Pogo
Determine
• Lift-off
i.
bounding
vehicle
loads
for each flight
event.
• Ascent
• Reentry
• Landing
j.
and recovery
Conduct an overall
• Use fundamental
k. Iterate
,
stress analysis to assess top-level
versus finite element analysis
with structural
designers
to converge
structures
Select TPS and thermal control system concepts
• Determine
thermal environments
from thermal
• Obtain
surface
• Develop
• Select
m. Develop
weight/density
design.
configuration.
(concurrent).
reference
trajectory
allowance
options
TPS and thermal
conceptual
control
propulsion
system
system
concepts
definition
(concurrent).
• Propellants
• Components
n.
• Weight
and performance
Develop
conceptual
avionics
• Components
• Redundancy
• Power,
156
weight,
cost
system
definition
(concurrent).
and natural
environments
Develop
O.
conceptual
and effects
on major
• Separation
systems
• Landing,
recovery
• Pyrotechnics,
p. Identity
of auxiliary
systems,
sufficient
for estimating
weights,
size, cost,
subsystems.
systems
etc.
initial production
Refine
q.
definition
design
content
and operations
plan.
of concept.
• Material, mass distribution,
• Induced environments
type and size of element,
etc.
• Sensitivities
• Margins
r.
Iterate
at each level to arrive
s.
Assess
attributes,
4.4.1.5
Overall
at a converged
technologies,
Integration.
configuration.
and risks in view of system
During
discipline
are heavily
involved
in all major
developing
concepts
the conceptual
activities
and project
requirements,
constraints,
to be mutually
compatible.
During
areas
operations.
reliability,
safety,
Consideration
schedule,
is achieved
by the leader
on the system plane,
and working
groups.
satisfy
Their
the requirements,
As shown
predominates
shown
function.
supported
focus,
in figure
integration.
77. This
The informal
modes,
The
integration
functional
plane
philosophies,
as an integrated
is required
At this stage
activities,
as shown
since
subsystems
as the design
progresses.
After
system.
If there
the conflict.
criteria,
and guidelines
of the design
process,
in the figure.
they represent
process
can significantly
should
be made to achieve
impact
balance
However,
engineers.
GN&C,
that these
into the conceptual
design
is conflict
This can result
in an overall
the informal
the informal
the core technical
the downstream
and convergence
design
stage,
Their
avionics,
initial activi-
operations,
or a variation
the subsystem
process.
is
design
and
eventually
assessments
Then
the entire
and balance
cannot
be achieved,
in changing
the requirements,
are
conceptual
then the
constraints,
sense
or rebalancing
them
among
activities
are at a lower
level
than the formal
input
from the design
assessment.
preliminary
that
integration
It is noted
to resolve
procedures,
systems.
very important
functions
managers,
attributes
system
thermal,
integrated
functional
with balanced
the initial
and discipline
design
mutual
is accomplished
with formal
propulsion,
are formally
The necessary
associated
by design
the vehicle-level
cost,
and represents
is accomplished
impact.
is reevaluated
sequence
integration
a significant
system
flow
all technical
and, in the conceptual
by the leader
could
design
is horizontal
and guidelines
from
integration
of
and guidelines.
is orchestrated
others
they
criteria,
consist
of performance,
engineers,
concepts
activity
for structures,
completed
discipline
procedures,
assessments
become
Formal
engineers,
of subsystem
have
constraints.
is developing
criteria,
attributes
the TRL
and the systems
activities
are received
integration.
above,
ties consist
that
and
leader
These
procedures,
inputs
on the concept(s)
and informal
philosophies,
79, the formal
philosophies,
by system
as stated
constraints,
informal
in figure
failure
with the aid of formal
the project
decisions.
this process,
is focused
operability,
compatibility
stage,
and associated
that are required
including
design
requirements.
These
inputs
and detailed
at this stage
and discipline
and avoid
the sub-
engineers
is
at this stage of the design
design
delaying
processes.
Every
the balance
effort
to a later
157
design
phase.
developed
In some
to achieve
programs
the balance
program
success.
In other
cases,
balance
in the conceptual
design
stage.
These
not be achieved
early
process
in subsequent
resulted
operational
program
has been delayed
delays
and rework
when new technologies
was delayed
shortcomings
were required
to be
mass
fraction
could
the conceptual
design
because
during
and in operational
complexity
which
increased
cost.
NotActive
/-----7
Conceptual
Design
! Preliminary ! !
Detail
I
Design I I
Design
l L ....
t
Tt
Manufacturing
! n
] Integration ]
I
land VerificationJ
l
Tt
Operations
it
FormalTechnicalIntegration
"_
_--" --
w inf--'ormation
Technicalintegration
4.4.1.6
of possible
Ideas
options
and
as a concept
to be evaluated
considered
in developing
included
as reminders
79. Conceptual
Options.
to satisfy
During
the mission
misses
of major
design
concepts.
options
should
Design
Stage
Products.
is the concept
or concepts
that have
been
downselected
will have
been
screened
should have appropriate
and assessments
In addition
other
outputs
process.
158
performance
margins.
with higher-fidelity
to the primary
that are carried
A listing
of these
products
Figure
An option
80 indicates
example
design,
the full range
that is not brought
subsystem
on this list are not nearly
The primary
product
to proceed
The preliminary
(the concept),
with the concept
is given
product
forth
options
exhaustive
in table 23.
of the conceptual
to the next stage,
for feasibility
system/subsystem
forward
stage of conceptual
to be
but are
that may be chosen.
Conceptual
concept
-'_
integration.
be explored.
The options
4.4.1.7
The downselected
stage---overall
the idea-generation
statement
the cut by default.
candidate
_
• Inlotmal
- DesignFunctionand DisciplineEngineers
- FunctionalManagers
- Panels
• Formal
- ChiefEngineer
- SystemEngineeringManager
- SystemEngineers
- FunctionalManagers
- WorkingGroups
Figure
"_" --
at a relatively
design
preliminary
low level
stage will entail
design
indepth
stage
design.
of detail
and
trade studies
definition.
activities
of the conceptual
or are retained
as a record
design
stage
produce
of the downselection
Top-Level SubsyslemCategoriesfor Trade Options
• Propulsion System
• Control System
• Materials System
PropulsionSystem
• Liquid
RP-L02
LH2-L02
RP-Air Breathing
• Solid
• Hybrid
• Aerodynamics System
• Structural System
• Avionics System
• Thermal System
• Flight Mechanics/Trajectory Constraints
• Pressure Augmented
• Engine Cycle
AerodynamicSystem
• Lifting Body
• Control Augmentation
Flight Mechanics/TrajectoryConstrainls
• Flight Mechanics
- Staging
• Single
• Multistaged
• Parallel Burn
• Air Assist
• Air Launch
• Guidance loop Closure
- Early
- Deferred
-Open
StructuralSystem
• Main Frame
Composite
Metallics
Hybrid
• Casting
• Disturbance Accommodation Approach
- Wind Biasing
• Generic
• Short Term
Propulsion Performance
Anomaly Accommodation
• Welding
• Fastener
• Tankage
Integral/Conformal
Nonintegral
Lines
• Internal
• External
• Shape Size L/D
• Bulkhead Configuration
AvionicsSystem
• Distributed/Centralized
• Redundancy Level
• Degreeof Autonomy/Self Check
Thermal System
•• Active
Passive
Metallic
Ablative
• Integral with Airframes
• Nonload Path
Reflective
Heat Sink
Insulation
J
Material Systems
• Metallic
- Steels
ALs
Tis
• Composites
_
_
_
_
Figure
• Trajectory Constraints
G Maximum Acceleration
Q Maximum Dynamic Pressure
o_ 13Pitch and Yaw Angle of Attack
Separation Attitude and Orientation
Thermal
Atmospheric Winds
Azimuths
Orbit
Mixture Ratio
Launching Sites
Special
• Dynamic Pressure/Mach number
• Thermal
• Manufacturing Options
- Casting
- Extrusions
- Welding
- Fasteners
- Milled
• Chemical
• Machined
80. Conceptual
design
stage---options
and
ideas.
159
Table
23. Conceptual
design
stage
products.
EstablishProgramSlralegy/Philosophy
• List of constraints
(mandatoryrequirements)
• List of preferences,
criteria,andweightings
• Uncertaintylevels;e.g.,3c, for systemand combination
approachfor survivablefailuremodes
• Failuretolerancerequirements;e.g.,FS/FS/FO;
engine(s)out
• Verificationphilosophy;e.g.,prototype/protoflight
GeneraleSystemsConcepts(Ideas)
• Systemsketches;includesvehicleconfiguration,
manufacturingprocess,and operations
• Top-leveldiscriminators
- Performancecriteria/constraintsand margins
- Derivedcriteriaand margins
-Weighting factors
EvaluationofAlternativeConcepts
• Foreachconcept
- Pointdesign
- Sensitivities
- Uncertainties
- Margins
• Conceptvalidationprovidedby functionaldisciplines
• Performanceparametersfor eachconcept
• List of nonmaturedtechnologies
- DefineTRL's,cost, andtime to maturity
• Riskdefinitionandmitigation
-Estimate of risk levelsandtheir consequences,
includesfailuremodesdefinition
• Attributematrixfor eachconcept
4.4.1.8
Managing
To Ensure
Proper
having
the right skills, the right tools, excellent
desired
synthesis
guidance
which
while
avoiding
is reiterated
selection
Put sufficient
• Ensure
concepts
design
effort
that options
is critical.
and process
the process.
selection
leadership
which
depends
on
enables
the
Experience
has led to the following
of life-cycle
cost is locked in by the
section:
The large
will not correct
into front-end
majority
a flawed
engineering
are fully explored,
only after appropriate
eureka
the concept.
• In early
phases,
discipline
specialists
depend
on sizing
program
alone.
•
concept
concept
(quality
selection.
lever).
converging
with successive
refinement
(greater
convergence,
considering
all the concepts;
detail)
and requirements.
• Pick a concept
160
learned
Proper
that is selected.
• The best detailed
•
Selection.
communication,
that can delay
in the lessons
• The right concept
concept
pitfalls
Concept
Avoid concepts
having
too many
must assess
technologies
validity
of sizing
at low TRL's.
program
i.e., do not
results.
Do not
of
4.4.2
Preliminary
and Detail
Preliminary
design
defines
Design
Stages
takes the concept(s)
that was downselected
more
trade
it in significantly
detail.
Major
subsystems.
System
attributes
of performance,
detail
design
stage
continues
the refinement
design,
and producing
Preliminary
definition
series
the drawings
design
as better
and
detail
data are obtained
design
having
a typical
4.4.2.1
Design
Cycles.
A design
propulsion,
trajectory,
cycles
(sometimes
special
cycles
a consistent
etc. work
called
loads
(sometimes
and cost
are determined
the
necessary
to go into manufacturing.
much
the
cycle
together
Both stages
proceed
definitions;
Space
to study
design
entail
increased
operational
is the Space
Shuttle
however,
these
usually
good
fidelity.
The
and
the
design
in a
and
had five design
special
problems.
revealed
are another
complexity
functions
of the structures,
Shuttle
is not initially
in operations
component
convergence
the designs
The
Changes
the
toward
cycles
arise when a phenomenon
specify
paragraphs.
and are not contradictory.
changes.
and
in refining
and three or four abbreviated
minicycles)
and
among the design
i.e., where
or test and must be dealt with by design
shortfalls;
with
process
of activities
stage
subsystem,
in the following
is a sequence
set of subsystem
system,
same
discussed
design
to balance
detailing
follow
basic pattern
cycles)
called
are conducted
from tests and analyses.
cycles
that produces
weight,
process,
and specifications
of design
disciplines
studies
by the conceptual
means
The
by analysis
of dealing
with
or constraints
on launch
coupled
with lift-off
availability.
An example
ignition
of a special
overpressure.
with (roads
minicycle
Not only did the complex
too high if not considered),
accommodated
by design
system).
external
Many
changes
multipoint
lift-off
dynamics
dynamic
constraint
problem
have
but also the high overpressure
energ3'
at SRM
ignition
to the vehicle
tank protuberances,
hardware
and the launch
etc., had to be redesigned
facilities
(water
to be dealt
had to be
suppression
and qualified.
Many design cycles must deal with a critical issue in a short period of time. The question
How do we know when a cycle or cycles are complete?
Generally,
there are two types of criteria:
°
The first criterion
is task completion.
design
It will take
changes.
making
use
accomplished.
of parallel
is not complete
been
solved.
Where
other
problems
design
cycle,
amount
of time
where
possible.
The
until all gates
it is clear
requiring
including
a design
sensitivity
cycle
each
task
until
all the
are met; in other words,
has
a new baseline
is developed
to quantify
top-level
number
is around
three: one each for PDR,
verified
models,
a gate for this cycle only. The Space
for the next
study results.
how many
design
cycles
will be required.
The
requirements
have
an effect
on the cycles
required.
The
cycle
include
Vehicle
CDR,
and DCR. At DCR,
Configuration
Shuttle
the design
had five design
(IBVC)
are
or if
have surfaced,
discipline
tasks
the problem
remains
data and special
sequentially,
to be done,
of the design
and the
Baseline
is not over
and make appropriate
refinement
It is not possible
were called Integrated
performed
for--
in the process,
to accomplish
cycle
and criteria
that further
system
evolving
all the tasks
a given
efforts
2. The cycle
Complete
arises:
cycles
complexity
must
during
I, II, III, etc. In addition,
of the
minimum
Phase
minicycles
all the
C which
were
161
•
Overpressure
(STS-1)
• Aerodynamic
problems
(STS-1)
• ET protuberances
•
-
Minicycles
Two-duct
-
Wide
•
throat
Advanced
Space
development
had three
cycles
and several
minicycles,
techniques
the design
can be accomplished
Node gusset
-
Common berthing
Meteoroid/debris
that is desirable,
will occur,
that with modem
but even with the most efficient
design
creating
nature.
allocation
major
approach
4.4.2.2
Activity
process,
which
Experience
systems,
has
problems
the schedule
and raising
cost. The design
the
compartmentalization/
with
current
cannot
iteration.
Sequence.
The previous
sections
This section
activities
sequencing.
the design
sequence
will be addressed
trajectory,
G&N,
control,
propulsion
and avionics
structures,
thermal
at a summary
developing
a minimum.
design
consistent
indicating
without
appear
effort on high performance
Certainly
and
In this document,
shown
two cycles
design
in one cycle.
end up extending
a realizable
requires
approach,
from the mainstream
minicycles
Ensuring
such as:
mechanism
shields.
that if you cut too much
violate
chamber
turbomachinery
Station
think
design
combustion
-
Some
shown
in engine
manifold
of those
in detail
similar
summarizes
primarily
functions,
level only. Also,
the specifics
manufacturing
can be expanded
of this document.
design
have dealt with various
key elements
from the perspective
and system
interfaces
design
aspects
design
to the above design
Propulsion,
functions,
of the
of this sequence.
of the aerodynamics,
function.
with materials
functions.
and tasks
It will include
and manufacturing
avionics,
are
materials,
but this is beyond
and
the scope
A design cycle in either preliminary
design or detail design follows the same basic sequence
but
with differing
levels of detail and fidelity of input data. The activity sequence
of the interacting
design
functions and disciplines
is similar to that of the conceptual
design stage which was illustrated
in figure 77.
The starting point, however,
is the baseline
design of the previous
cycle, along with its sensitivities
and
supporting
data. The first cycle
conceptual
design
activities
the output
of the
A number of activities
can proceed
in parallel and should do so where possible.
However,
require as input the results from other activities and so must be accomplished
sequentially.
some
The
illustrated
a,
design
stage
has as its starting
point
stage.
following
on figure
of the preliminary
are the
81, which
major
steps
in the
will be discussed
activity
sequence
for a design
cycle.
The
steps
are
at the end of this section.
From the previous
cycle, collect and review the requirements
and constraints;
the philosophy,
procedures,
and criteria; the baseline
design, including
sensitivities
and supporting
data; and
any identified
problems
or design shortfalls.
Determine
the direction
of modification
for the
upcoming
design
cycle. The systems plane, in consultation
with the other design functions,
allocates requirements
and constraints to the design functions, reflecting the desired modifications.
162
b. Propulsionprovidespropulsionsystemcharacteristics,basedon its designcycle and on the
aboveallocations.
c. Structuresdesignmodifies
previous
cycle's
baseline
the vehicle
or expanding
d. Aerodynamics
provides
updated
on updated
configuration,
wind
specify
stiffness
e. Ascent
requirements
aerodynamic
tunnel
forces,
tests,
analysis
margins,
reserves,
under constraints
developed
at both the systems
•
in order to have a tractable
Targeting
points
• Abort/failure
•
Dynamic
• Axial
•
•
for staging
targets
pressure
and pressure
Aeroelastic
on dynamic
to determine
of the
distributions
based
design
include
and payload
limits
stability
the payload
is assessed
to
performance
of the
the flight path of the vehicle
level and the discipline
and reasonable
problems
pressure.
and fuel bias, and to determine
level. Typical
constraints
at least the following:
and insertion
for engine
out
for aeroelasticity
acceleration
resolving
of its definition.
and analyses.
is conducted
toward
moments,
constraints
including
levied
directed
the level of detail
or trajectory
trajectory/performance
vehicle,
configuration,
for human
and loads
passenger
Angles of attack for loads
Thermal constraints.
The trajectories
f. Reentry
can be modified
and recovery
and variations
g. Design
trajectories
design
are chosen
parameters
variable
is determined
control
variations
flight
to represent
response
to determine
and the transition
analysis
response
the control
logic for stabilizing
additional
constraints
i. Loads
indicator
trajectories,
locations.
choice,
operational
missions,
during
in initial
to winds
reentry.
and controlling
while
dispersed
reference
and other
This basic simulation
the vehicle.
like q-alpha
logic
control
responses
with other information
flight
events
to produce
estimates
of structural
trajectory,
control
indicator
models
estimates
of heating
use
at critical
locations
response,
and
runs.
plus parameter
high-q
loads
is adjusted
authority
the control
produce
trajectory
during
combine
j. Thermal
a physically
ascent
is also used to determine
The control
and q-beta,
the
of the desired
trajectories
forces
These
to envelop
maintaining
models
and
conditions
analyses.
maximization
by numerous
for the design
thermal
attempting
for a reasonable
guided
response
of load indicators
and
such as a load indicator,
is performed
the vehicle's
dispersions
loads,
combination
by a judgment
considering
for control,
potential
a variable
The parameter
limits.
parameters.
are generated
to maximize
trajectory.
within
are determined,
and vehicle
trajectories
realizable
h. Basic
trajectories
in environmental
reference
for operations,
limits,
about
etc.
the vehicle,
at pertinent
configuration
to meet
vehicle
information
to
on the vehicle.
163
k. Approximationsof designcapabilitycorrespondingto the loads andthermal indicatorsare
determinedfrom theexistingdesigndescription.
The loadsand thermalindicatorsare usedto provideestimatesof the structuralandthermal
systemdemandthat are comparedwith the approximatedesign capabilities to determine
adequacyor impact.This informationguidesdecisionson potentialfurtherdesignchanges.
m.
In addition
to these
activities
that
are focused
operability, safety, and other attributes
and allocations.
Also
fed by the design
that constitute
items
the indepth
i, j, and k above.
n. G&N
These
systems
off-nominal
sensors
trajectory
phase
the cost,
and compared
are detailed
analysis
and are the basis
are synthesized
performance
reliability,
with requirements
and
design
activities
of the approximations
discipline
and loads
analysis.
Control
systems
are synthesized
and actuator
and analyzed,
loss with
balancing
used
in
the magnitude
the
accuracy
(cost,
Abort
and contingency
targeting
are a major
generates
dynamic
requirements.
control
Sensor
performance,
the following:
and
dynamics
outputs
of the design,
for each flight
and software
and effects.
avionics.
q.
include
dispersions
o. The structural
p.
reference
determination
on system
of the design are assessed
models
and analyzed
in detail,
requirements
are identified
complexity)
of the elastic
including
consideration.
structure
all pertinent
and updated
of
of the
for use in
nonlinearities
in coordination
Making use of the dispersed
response data and the chosen method of combining
consistent
vehicle loads are determined
for each major loading event:
with
uncertainties,
• Transportation
• Lift-off
• Ascent
max q
• Ascent
max g
• Docking
• Reentry
• Landing
Iterations
through changing
E
and recovery.
with other disciplines
may be necessary
to bring
the aerodynamics,
trajectory, control, parameter
Acoustics/overpressure
elements
where
determined
s.
164
for components
Aerothermodynamic
updated
environments
this high-frequency
design
and
reference
are determined
the loads
variation
and
to within an acceptable
range,
approach,
criteria, etc.
applied
as loads
loading
is significant.
The vibroacoustic
and is converted
to component
design
plume
trajectories
heating
environments
and configuration.
to the structural
environment
is
and test criteria.
are determined
consistent
with
the
Thermal
analysis and design can be done
are determined
from aerothermodynamics,
t.
and
other
on-board
environments,
system
designs
TCS
for components
design
functions
with temperature
of materials
and components.
Based
on the
systems
thermal
and thermal
systems,
Stress
and
Designing
the analysis
life
thermal
data
specified
criteria.
Stress
Deflection
to obtain
critical
design
cycle
and
and buckling
analyzed.
design
and
insulation,
activities
and time
If criteria
interact
and
with
systems
other
is crucial
provides
the basis
for
TCS likewise
requires
selection
and
temperatures
and
gradients
are
design
are determined.
process.
Outputs
of the thermal
deflections
strongly
natural
systems,
and compartments
iterative
the
to other
design
design.
configuration,
are
As in
using
determined
stability
are analyzed.
to failure
and to develop
detail
is set to be appropriate
and
Fracture
the loads
compared
and fatigue
fracture
with
analysis
control
plans
for the maturity
are not met, either the environments
and
must
for
of the
be reduced
or
must be changed.
Structural
design works
modifications
to correct
closely with the stress and durability
structural
strength
or life shortfalls.
disciplines
Meanwhile,
receives
inputs
sion, avionics,
from and interacts
with the other design functions,
and auxiliary
subsystems.
The structural
design
accommodate
these
other subsystems
as their designs
a primary packaging
and integrating
function.
baseline
for the next cycle. If modifications
indicated
propellant
and insulation
structural
for the baseline
fields
cycles
cryogenic
and passive
after convergence
parts. The level of modeling
being
the structural
of the
and
of the vehicle
of components
is part
environments
for TPS
above,
are performed
provided.
fracture
designed
are made
analyses
active
induced
design
selection
requirements
environments
and disciplines
are performed
W.
These
Material
the TPS and insulation.
functions
W.
and compartments.
sizing
other
on these
for TPS's,
sizing
calculated,
Based
are accomplished
and disciplines.
and, in conjunction
U.
inputs.
in parallel with loads analysis. Induced environments
plume heating, propulsion
system inputs, avionics,
by successfully
meeting
criteria
evolve.
to identify
structural
including
thermal, propulis modified
as required
to
In this role, structural
The structural
are complete
design
design
design as modified
or are essentially
design
has
becomes
complete
the
(as
and
interfaces),
drawings
and
specifications
detailed
discipline
analyses
and
design
are
finalized.
In parallel
with
the
summary-level
described
above,
there
are special
analyses
but which
are handled
separately
from
and
of specific
the primary
phenomena
such
as flexible
mode
transients,
docking
transients,
etc. Provision
loop, including
appropriate
x. Control
margins.
stability
analyses
models.
These
elastic
and slosh
algorithms
produce
are
stability,
satisfactory
stability,
typically
using
activities
and designed
for,
are stability
or transient
stability,
separation
aeroeleastic
is made for these effects
requirements
analyses
that must be assessed
loop. These
pogo
are shown
conducted
baffle
Confirming
to confirrn
design
or "headroom"
Examples
slosh
modes.
simulated
control
phenomena
in the primary
design
in the next four items.
elastic
body
dynamics
and algorithm
and
requirements
are run with the baffle
models
slosh
dynamics
for stabilizing
and stabilizing
margins.
165
y.
Aeroelasticstability is assessed
by structures,aerodynamics,and(if pertinent)control. The
designis movedawayfrom anyaeroelasticstabilitylimits, allowing adequatemargins.
z.
Pogostabilityanalysesarerun to determinethe requirementfor a pogosuppressionsystem.
aa.
Special
transient
response,
landing
ments
events
are
on the vehicle
design
Completing
the design
cycle
bb.
Concurrent
with the above
CC.
involves
enced
by the primary
recovery
systems,
applicable),
ing design
the following
activities
design
which
separation
clearance,
docking
produce
require-
assessments
systems.
activities:
design
but are less
systems,
and analysis
coupled
compartment
activities
to it. These
venting
design,
that are influ-
include
landing
and
life support
systems
(if
analysis.
with the above
activities
and
of these
ground
are related
cycle
liftoff
etc. Results
and its interfacing
pyrotechnic
of this document).
including
response,
and breakup/disposal
Also concurrent
scope
assessed,
or recovery
are the major
propulsion,
can be described
in similar
detail
to the items
the other
parts
of the system
They
interact
with
avionics,
materials,
and manufacturabove
(beyond
design
the
to ensure
compatibility.
dd.
All subsystems
of analysis
design
ee.
models
verification
and development
The end of the cycle produces
The
plans,
production
testing
produces
hardware
process
of the designs
the baseline
the drawings
and
software
Verification
an important
part of the
to begin
and specifications
for entering
the production
are produced
and
verified,
involving
the next cycle
many
or, if
stage.
components
and
steps.
while
not violating
safety
constraints.
activity
sequence
discussed
above
has
design sequence
can be illustrated
delineated
in section 3.5. Recall,
from the above activities,
that the vehicle
a multiplicity
of facets.
maximizes
A clear
drawing
heavily
its operational
visualization
of the
with the application
of the various categories
of activities and/or models
these models consist of a generalized
model, specialized
models,
and
discipline
specific models. Shown in figure 81 are the design process
and their association
with the three models. This illustration
indicates
166
constitute
plans.
and sensitivities
capability
to the models,
and operations
design
procedures
and constraints
are developed
gg. Operational
on the analysis and verification
program
to ensure
The
plans,
maturation.
complete,
ft.
develop
as well as how the models
are applied
activities (i.e., activities a through gg)
where the various activities fit relative
after the initiation
of a design
or a design
change.
Specialized
Models
General] Model
/] \
IVehicle
Design
I Initiationor
DesignApproved
I
,c ano
Discipline SpecificModels
II
__
r_]
L.J
7
L
_[_'_
_ _
iI
/
I
_---_"J
'ndicat°rM°d_l I I
I
/
'l
=I k.Capability
L_
_
4
ee.Drawingand _,_ Drawings/Spec ff. Production
I SpecificationsI I
Released J J andVerification H
_
}
Procedures I
gg.Operational
|
i
._
Figure
Subsequent
model.
Iterateif Required_-i
Paralleldesignof propulsionsystem,
avionics,materials,
manufacturing,
andothersystems
to initiation,
81. Design
the characteristics
It can be seen that properties
The major
activities
of the trajectory
are determined
using
(i.e., g) drive
the specialized
models
of the trajectory
capability,
and indicator models. The indicator
models are included in the generalized
model to
the loads and thermal demand versus the capability
of the design. In a parallel fashion, results (e.g.,
the specialized
models
demand is within
the capability
and has acceptable
into the production,
verification,
and operational
For every
subsystems
iteration
are coupled
of the design,
to the vehicle
tions is required
to be evaluated.
that of the vehicle
activity
developed
to illustrate
that describes
While
sequence.
the subsystem
figure
system
attributes,
margins,
When
the
the total
and the hardware
goes
(see bb and cc). Since
many
activity
of their interac-
an activity
sequence
similar
to
a figure
parallel
or similar
to figure
81 could
be
sequence.
It would
specialized
include
a generalized
models
and discipline
vehicle
design,
a similar
is selected,
similar
vehicle
to illustrate launch
a payload
etc.), the impact
through
for operations.
For instance,
after
applied
to assess the impact
of the payload
on the vehicle
model
to assess the operational
is applied
is approved
avionics,
developed
capability, the generalized
wind limits.
to the capability.
are assessed
is accomplished
and the associated
81 has been developed
the design
subsystems
subsystems,
cycle
are drawings/specifications,
are also compared
(e.g., propulsion,
For those
design
activities
stages.
all primary
This evaluation
their specific
the discipline
and the disci-
design
assess
from
from
the generalized
specific
determination)
outputs
interactions.
pline
stability
models.
process
and vice versa. Assuming
constraints
model
models.
illustration
generalized
that the demand
could be
model
is
meets the
for flight; e.g., day-of-launch
167
5. PROCESS
The major focus of this document
characterization
can then serve as a baseline
As discussed
NASA
order
in section
and the aerospace
to meet
There
second
are two categories
attain
of technologies
process
significant
advances
applicable
technologies.
propulsion
concepts,
technologies
be advanced,
and major
the conduct
of the design
recognizes
that
more capable
5.1
This category
by Rick Fleeter
was just sufficient
energy
Vehicle
transfer
and
that address
and cheaper
process
system
technologies
in
gravity
propulsion
concepts
the effects
to new
In addition
to essential
itself must be improved.
the experience-based
process
It should
are just
ideas
design
process.
5.2.1
Design
itself must
be improved.
that
Shortcomings
of the current
of the process
This is the subject
are intended
design
in section
is fragmented
be
of the problem
as
presented
materials
and
the molecules
range
alternative
in cost, reliability,
from
avionics
and performance.
need to be identified.
technologies,
the design
by application
of
7. In addition,
the technology
of
of the section.
and
action
all inclusive.
toward
They
improving
for Improvement
and its history
and not well organized,
process
can be improved
here are by no means
thought
Approaches
process
in splitting
indicates
areas
inferior
designs.
at least the following:
The process
must
in this category
of the remainder
to stimulate
and Potential
that
Technologies
identified
that the ideas and suggestions
suggestions
An examination
learned
The
of the physics
new technologies
hardware/software
and effectiveness
and lessons
Process
Process
in vehicle
principles
be noted
and
advances
The efficiency
and matured;
Design
It is
a technology
available
structural
explored
5.2
systems.
this objective.
of launch
toward
to get to orbit. Technologies
such technologies
are being
of
Technologies
he said that the energy
to overcome
technologies
systems.
Several
•
systems.
(1) hardware/software
aspects
is itself
to achieve the needed major advances
168
launch
the obvious
are underway
ways of optimizing
12 when
includes
These areas must be pursued
including
reliable
this objective:
systems.
the design
design
process.
This
on the current process.
in launch
the physical
efforts
Hardware/Software
deals with the different
was so well expressed
(propellant)
etc.,
toward
The first category
new
in order to achieve
advanced
must
for low cost, high performance,
that these
category
advanced
is a clear need
community
and (2) design
materials,
essential
is to characterize
the launch vehicle
to identify and evaluate improvements
this need.
technologies,
new
1.1, there
IMPROVEMENT
producing
of shortcomings,
the
• There are deficienciesin the ability to predict(model) designperformance,especiallycost,
reliability, andoperability.
• Synthesisis anidea-drivenprocessthatmaymisspromisingconceptsif thedesignerstayswithin
his experience"box."
• Thereis low confidencein the conceptualdesignstagewherea high percentageof the costis
lockedin.
• The designprocesshasdifficulty in handlingthevastquantityof requireddataandinformation
andin providingnecessaryvisibility to all involved.
Newdesignprocesstechnologiesshouldbe soughtto addresstheabovedeficiencies.Approaches
for high leverageimprovementinclude-Reductionof processfragmentation;moreseamlessdesignin
- Subsystem,designfunction,anddisciplinefunctioncompartmentalization
- Designfor all missioneventsanddesignstages
• Improvedmodelingandknowledgebase,especiallyfor cost,reliability, and operability
More
direct
-
Conversion
-
Ideation
of requirements
to concepts
and visualization
of design
conceptual
design
-
Better
synthesis
and higher
-
Scaleable
There
and designs
space
process
representations
for efficiently
Evolutionary
following
approaches
Improved
• Means
5.2.2
synthesis
fidelity
models
that mature
conveying
into subsequent
and displaying
necessary
are many
options
for fine
tuning
the present
design
Requirements
and Criteria.
and criteria.
information
process.
Several
detailed
criteria
that many
times
they dictate
the design
documentation,
procedures,
etc., are often very excessive.
on excessive
test, etc. No use or very
requirements.
A key
the system
limited
of understanding
in aerospace
forms.
stated
is insisting
instead
The tendency
This takes many
various
making
design
to all participants.
are discussed
in the
paragraphs.
5.2.2.1
NASA
stages
Improvements
into the form of requirements
Required
design
documentation
use is being
task for fine tuning
efficient
and allowing
and preventing
failures.
and leave
little
very
and traceability
made
the
of electronic
system
of failure
for innovation
work
of creativity
all our lessons
is replaced
by
are so
and creativity.
in the Space Station
of not only hardware
databases,
modes
The requirements/criteria
room
Currently
is to strongly
for the interjection
has been to place
Analysis
program,
but also all analysis,
etc., to meet the documentation
the requirements
and criteria,
and innovation.
169
5.2.2.2
to designing
Design
for Simplicity.
for simplicity.
There
The "Experienced
are many
Practitioner"
measures
of simplicity
in Total
Design 3 and
survey (section
that can be used
7.1 ) has many references
as guidelines:
• Simple load paths
• Number of functions
• Number
of parts
• Complexity
• Number
of turnings
• Number
• Etc.
of steps/offsets
This
structures
very
is only
a partial
by load lines/paths.
complex.
Future
of incorporating
systems
list. Pugh
Others
illustrate
require
simplicity.
the approach
other
publications
in different
Improved
to essential
Modeling
aspects
Tools. Initiatives
of the design
• High
fidelity
simulations
• More
granular
operability
process.
for virtual
are in progress
These
Present
simplicity
designing
launch
systems
and implement
are
ways
more probabilistic
• Bottoms-up
cost modeling
to improve
methods
modeling
into the design
process
for smoother
interface
with current
modeling
using
geometry
as basis
• Rapid
modeling
techniques
to enable
5.2.2.4
Integrating
Various
design is for the dynamic
and durability
of sequential
analysis,
CAD
Discipline
specialists
analyses.
a greater
Analyses
of sensitivity
Into Single
to first run a load analysis
would be multidisciplinary
multidisciplinary
analyses
take different
form.
increases,
putting
any discipline
out of business.
without
number
top-down
• Load
transformation
matrices
• Stress
transformation
matrices
This process
(allow
Tasks.
The process
today for
and then pass the loads to stress analysts
analysis.
is more
cost models
analyses.
or System
These results are then passed to the designer
a better method
and simulations
flight
• Multidisciplinary
for strength
modeling
include:
and maintainability
• Embedding
structural
ways.
The key task is to study
emphasize
it into design.
5.2.2.3
related
of functions
At various
efficient,
Activities
directed
time consistent
stresses)
for design changes,
stages
of the design,
and confidence
toward
etc. Instead
the
in the results
this end are--
• Integrated
trajectory,
control, and loads
• Thermal
transformation
matrices
• Improved
• Combining
sizing programs
multidisciplinary
equations
into a single
system
• Applying
170
design
of experiments
for analysis
and test.
set and developing
codes
for the integrated
5.2.3
Revolutionary
As noted
as an immediate
1.1,
Advances
in the previous
means
revolutionary
section,
of increasing
changes
evolutionary
process
are
improvements
efficiency
required
in the design
and effectiveness.
to achieve
major
to stimulate
thinking
process
However,
advances
should be pursued
as discussed
in launch
in section
vehicle
cost
and
capability.
The following
advances.
current
discussion
is intended
changes
in design
(1) The
current
Revolutionary
design
process:
process
technology
process
does
not arrive
compartmentalization/reintegrations,
its ad hoc experienced-based
of limited
is too long and costly.
fidelity;
The
and (2) the process
ideal design
mal design
process
would
in a single step. Achieving
be an automated
such an approach
in the interim.
Until the ideal one-step
in the multistep
process
analysis,
and reintegration.
5.2.3.1.
We can consider
advances
in each
technology
but also to design
currently
functions,
update
Synthesis
and
Design
depends
on the designer's
ideas
technology
in this
area
knowledge-based
leaps
systems
to convert
for visualization
of the design
engineering,
using,
include
Technology.
several
fronts,
including
combining
metrics,
and full probabilistic
Interactive
approaches;
multidisciplinary
Potential
discipline
design
Information
analyses,
synthesis,
compartmentalization,
performance,
any design
on an ad hoc basis.
shape
use
cost,
synthesis
Possible
of artificial
and automated
intelligence
computerized
and Communication
and electronic
tools could
improve
from
locations,
multidisciplinary
computerized
tools would
consist
and
techniques
synthesis
or inverse
might
in fidelity,
be pursued
inclusion
along
of life cycle
enablement.
and software
remote
to
optimization.
technology
advances
approaches
System
As a design proceeds
through the various stages from the concept stage to the operational
there is a need for an interactive
information
and communication
system (I2CS). The system would
of various
etc.),
or design
into algorithms;
and topology
in analysis
major
we will need to seek
compartmentalization/
(i.e.,
optimization;
advances
be the guiding
Generically
and rules of thumb
like structural
but should
areas.
Currently,
idea
judgments
analysis
and stages of the program.
Technology
areas as possible into a seamless whole.
base
stimulus
of its many
into an opti-
system/subsystem
and experience
approaches
Analysis
Technology.
designer's
space;
for example,
5.2.3.3
5.2.4
Update
with
requirements
is achieved,
accommodation
operational
events (lift-off,
atmospheric
flight, reentry, etc.),
advances are needed to unify as many of these compartmentalized
5.2.3.2
because
by compartmentalization,
of these
not only to vehicle
requirements
revolutionary
problems
and its fragmented
future
approach
Technology.
is applied,
disciplines,
design
that converts
that is characterized
Compartmentalization/Reintegration
reintegration
synthesis,
lies in the distant
revolutionary
needed
the two general
at the best
process
star target for our efforts
advances
and ideas toward
can address
tools to facilitate
the information
model
all aspects
flow, interactive
implementation,
of the design
process.
team communications
etc.
Specific
These
hardware
including
examples
stage,
consist
those
of various
of the following:
171
•
A residenceand/orplaceholderfor the design descriptionand specifications, associated
attributes,ICD's, and supportingdata (this tool could be basedupon the design process
characterizationmodelalongwith theNxN andIxI diagrams)
A realtime interactivecommunicationssystem
A management
relatedinformationsystem(this tool would includethe WBS, costspending
profiles,allocations,reserves,schedule,etc.)
•
•
•
An electronic
•
A flight performance
•
performance
An advanced
indicators
versus flight time
interactive
multidisciplinary
architectures
per given
•
A virtual
•
reality
with fidelity
simulation
with fidelity
requirements
design
system
tool
In addition
to the above
examples
there
examples
of these
features
by all participants
and communications
and constraints
reintegration
with
are certain
interactively;
residence
users
and/or
tracking;
trade
tracking;
scalable
placeholders
hypertext
insensitive.
Other
manufacturing
and testing
real time video
acquisition.
tools are needed
to improve
will provide
much
I2CS design
needed
improvement
The potential
improvements
of the correct
ingredients
concept.
in meeting
design
unique
the mandate
currently,
in the design
listed
above
particular
for major
to enable
tools.
these
permits
controlled,
simultaneous
compartmentalization
and
includes
prompts,
etc.;
action
items
searchable
the best
and interrogatable;
video
efficiency
conferencing,
and
and effectiveness.
This
real-time
It is imperative
and
within
the
that the requirements
design
for
in collaboration
with the tool developers.
implementation
of the system
would
While
stage.
the high leverage
provide
process.
can apply
attention
and developing
cost,
data
telephone,
process
to achieve
and constraints.
by the STS designers
stage,
Discovering
the design
capability
for I2CS exists
revolutionary
effect of the conceptual
172
the
e-mail,
in real time
graphics,
file transfer;
also include
etc., requirements
tools be developed
of the technology
potential
the designer
cost, reliability,
would
related
or
performance,
configuration
implements
for data,
seamless
and platform
The I2CS design
framework
subsystem,
decisions
system
for
algorithm
element,
include
be secure,
for all design
for growth;
features
that
key
that can search
by optimization
system,
counterparts;
characteristics
system
that are required
must
industry
stage that displays
of their design
models
tools
by multiple
etc.;
the
but driven
features
with
traceability,
study
"design-to"
are as follows:
assessment,
performance,
systhesis
on the vehicle
and compatible
impact
system
optimization
can assess the realization
synthesis
stage
with the design
with
interactive
etc.
viewing
consistent
An
operations,
accessible
with the design
that can focus
safety,
Typical
consistent
part where the design participants
reliability,
and
mock-up
to any design
Noting
should be given to technologies
revolutionary
improvements
design
in launch
process
cost,
that enable
technologies
capability,
selection
are essential
and schedule.
a
6. ILLUSTRATIONS
This chapter
Space
Shuttle
section
6.1. Section
illustrates
conceptual
6.2 illustrates
ics with a loads modeling
Saturn/Apollo
6.1
When
configuration
of Space
design
Shuttle
modifications
process
as political,
Political
Activities
considerations
itself. These
economic
environment,
frame (see table 24).
and headed
directions
in space
Mars exploration,
examples.
An overview
of the
C configuration
cycles
the design
for flight mechan-
process
Shuttle
history
with some
Phase
A Through
is given
in
comparisons
of the Shuttle
Phase
the
etc. Much
the National
C) which
design
to
of the Shuttle
program
and constraints
government
formed
They
agency
a Space
Agnew.
Task
roles
Group
This group
recommended
option
resulted
being
three
composed
ambitious
expendable
and series
orbiter/expendable
versus
In 1970, NASA
of Defense
(without
trade
stages,
categories
parallel
burn.
boosters;
(TSTO).
Shuttle
Class
(DOD)
of engines,
a Space
Paine
options
(SSTG)
of
and priorities,
the
1969-1971
time
the
NASA
including
and Air Force
the Nation's
a lunar
for both an Earth
in the economic
led by Leroy
broad
cross-range
II--stage-and-a-half
next
station
Space
and
Station
environment
Day which
of
defined
vehicle
characteristics
such as
capability,
payload
launch
size,
three classes
of vehicles:
Class 1--reusable
expendable
tanks;
Class
Seamans
established
Ill--reusable
first choice.
and Secretary
STS Committee.
of senior
unaffordable
among
The SSTG defined
Class HI was the SSTG's
Administrator
studies
during
book
but also the form
needs
with identifying
a $5B per year program
Task Group
versus
and interests
was charged
a Space
and recommended
from national
of its
by external
the excellent
not only the existence
formed
reusable
determined
from
of
and major
the magnitude
was
comes
the history
selection
directions
as being
NASA
concept
shaped
all three options
missions
material
C
to consider
illustrates
selection
of the
rejected
of Shuttle
program
an overview
Nixon
Meanwhile,
it is instructive
System.13
Nixon
classes
two-stage-to-orbit
vehicles,
Phase
Transportation
the least ambitious
Shuttle.
From
Space
by Vice President
exploration.
provides
budgetary,
and multiple
In 1969 President
personnel
for launch
to which
6.1.1
design
History
A through
such
Shuttle
historical
Phase
by describing
extent
The Histm T of Developing
Department
using
from Space
(Phase
and the
Shuttle,
Political
Design
This section
Space
orientation,
primarily
process
considerations,
and a Space
the time.
process
subsequent
integration
drawn
the design
design.
design
the vehicle
and
technical
example
examining
vehicle
conceptual
of the design
process
and X-33.
Overview
past launch
aspects
design
OF PROCESS
of the Air Force
The White
House
rejected
the resulting
a NASA/
proposal
for a
Station).
173
Table 24. Space
Shuttle
history--political
activities.
CONCEPTUAL DESIGN STAGE PRODUCTS
February 1969
• Space task group formed by Nixon
• Team:
- Spiro Agnew
- Senior NASA and Air Force personnel
• Recommendations:
- $8-10 B/yr Lunar Space Station,
50 person Earth Space Station
Mars Exploration
- $8 B/yr 50 person Earth Space Station
Mars Exploration
- $5 B/yr Earth Space Station
and Space Shuttle
• Result:
- Nixon rejected all three proposals
- NASA had to propose
• Space Shuttle first step
to Space Station
February 1969
• SSTG
• Team results:
- Leroy Day (Leader)
- Six missions defined
• Logistical support for
for Space Station
• Service low Earth orbit (LEO) satellites
• Propellant delivery to LEO
• Satellite service
and maintenance (LEO)
• Delivery of LEO payloads
• Short manned missions
- Trade studies recommended
• Reusable vehicle
January 1970
• MSC started inhouse
STS Design
- Concerned over _B RFP
requirements
- 8 x 30 ft payload bay
- Payload t0 K to 15 K
- Class 111
- Cross range 200 mi
- Orbit 310 mi 55°
- 30 flights/yr
- Cost $58 B
• Pilot fly back versus expendable
booster
• Off st_eifversus new engine
• 230 miles versus 1265 cross
range capability
• 15 K versus 50 K payload
• Vertical versus horizontal launch
• Sequential staging versus parallel burn
Defined classes of vehicles
I Reusable orbiter/expendable
boosters
II Stageandhalf expendable
tanks
III Reusable TSTO
(SSTG choice)
September 1970
• NASA administrator (Paine)/
Secretary of Air Force (Seamans)
Established NASNDOD STS committee
• Shuttle project rejected by White House
February 1971
• NASAAdministrator (Fletcher)
- Significantly reduced cost
- DOD committed to use it
for all launches
• Must meet all DOD requirements
- STSwas first program subject to
formal economic analysis
and requirements by OMB
- STS must be the only launch vehicle
during the 1980's and later
- Space TaskGroup (STG), DOD,
Presidential Scientific Advisory
Committee NASA American
Institute of Aeronauticsand
Astronautics (AIAA)--all support
STS development
- DOD requirements
• Payload bay 15 x 60 ft
• Payload 40000 polar orbit
60,000 due east
• Cross range 1,100---1500 miles
(issue: reentry heating)
- DOD CIA, NASA, etc supported
Shuttle as the only launch vehicle
174
Septem ber 1971
• D0D did not provide dollars
but- Contributed facilities for
orbiter construction at
Palmdale
- Presented united front with
NASA to Congress
New NASA Administrator
program
were
Government
to significantly
agencies
Shuttle
Management
orbiter
requirements.
was made
program
6.1.2
in reusable
Martin
Marietta,
enabling
vehicle
the
of a Shuttle
from
all involved
for all of its launches
from the numerous
vehicle
developed
economic
funds
agencies
with
a united
and
1980's.
The
by the Office
of
Palmdale
front
provided
agencies,
in the
requirements
but contributed
presented
facilities
with
NASA
for
to the
of the program.
work
plus in-house
contractors
study
with
aerodynamic,
and delta wing
(proceeded
to Phase
groups
of these working
groups
Figure
Center
discussed
the history
(MSC)
of spaceflight
(JSC predecessor)
and had
(see figure
82 and
issued
a joint
request
were
made:
studies.
Five
(MAC-DAC),
Lockheed,
Martin
Marietta
led to NASA
continuing
funding
for all of the four except
funding.
The
Air Force
concepts
on Class III vehicles
(fully
materials,
structural
variable
wing
and
awards
by Flight
reusable)
Dynamics
testing.
to these concept
studies
by industry
were chartered
to develop
the key technologies
and significant
history---example
(proceeded
Phase
by the
Laboratory
200 man-years
Categories
B). In addition
and North
oversight
and spent
wing
activities
(MM),
provided
straight
Shuttle
activities,
concept
internal
vehicle
political
(rejected),
had extensive
82. Space
during
work on stage-and-a-half
focused
body (rejected),
working
the previously
reentry
Douglas
were lifting
series of technology
Space
and
A 4-month
extensive
before
undertaken
launch
continued
Corporation,
began
configurations
Each
did not provide
and the Manned
(NAR).
who
along
was obtained
to formal
to acceptance
for the program
be the only launch
the acceptance
studies
(GD), McDonnell
The five NASA
of effort,
The DOD
agreements,
support
keys
to use the Shuttle
support
would
these
for integral
Rockwell
Aerospace
(FDL).
(RFP)
Dynamics
American
broad
that
A
table 25). In 1968, MSFC
General
obtain
The necessary
A of the Shuttle program
its foundation
determined
DOD committed
(OMB).
With
and Congress,
STS Phase
for proposal
cost and
that the Shuttle
and Budget
Phase
in 1971
was the first of its kind to be subjected
construction.
Administration
reduce
and organizations.
that it meet all DOD
a commitment
Fletcher
of orbiter
to Phase
B),
and government,
a
required
(see fig. 83).
expenditures.
A configurations.
175
Table25. SpaceShuttlehistory--PhaseA.
m
Year
October 1968
Integral launchand reentry
vehicle Joint RFP (MSFC
and MSC)
Requirements
• Focus
• PId (K#)
• Orbit (miles)
- Baseline
• Cross range (miles',
• Engine
October-December 1969
February 1969
NASA concept
study
_A results:
Effod
• 200 man years
• Extensiveaerodynamic,
materials, and structural
testing
Cost and safety
5-50
115-345
3OO
45O
MSFC
Four baselines
• Straight wing (Phase B)
• Deltawing (Phase 13)
• Variable wing (rejected:
complexity, etc.)
• Lifting body (rejected:
packaging, etc.)
Contractors
GD
MAC-DAC
Lockheed
MM
NAR
Configurations
• Ill (2)
• Ill (12); $5.9B; 21 months $67/#
• III + II (4); $5.5 B; $25/#
• ttt (25)
• III (1 + Opt); 52 months
GD (MSFC)
MAC-DAC (LARC)
Lockheed (MSFC)
MM In-house ($)
NAR (MSC)
Air Force Space Division
• Aerospace oversight
of NASA
• FDL (stage + t/2)
I
I
I
Headquade_
I
I
Concept Studies
Technology Working Groups
I
,,c I LM,FcL
I
Structures
I
Aeroelasticity
Propulsion
• Parallel Concept Studies
- Government and Contractors
J
TPS
• Identified Key Technologies
• Uncertainties
- Winds
- Thrust Vector Misalignment
- Rigid Body Aerodynamic Coefficients
- Thrust
Others
- Isp
- Weight
• Develop Key Technologies
- Fuel Residuals
Figure
176
83. Space
Shuttle
history--Phase
A concept
studies
and groups.
6.1.3
STS Phase
B
The convergence
of concepts
during
Phase
A led to the issuance
of a Phase
B RFP in 1970 for a
fully reusable
two-stage
vehicle (see fig. 84). Major requirements
of the RFP are listed in table 26. Two
orbiters were to be developed:
one capable of 230 miles cross range and the other capable of 1,726 miles
cross
range.
Go-around
air-breathing
engines
NAR/GD.
Two months
capability
on both
was required
vehicles.
Two
later, requirements
for both
teams
were revised
orbiter
were
and booster,
awarded
to increase
which
contracts:
payload
implied
the use of
MAC-DAC/MM
from
15,000
to 25,000
and
pounds
and to specify JP--4 fuel for the air-breathing
engines (safety issue). During the Phase B activities,
both
teams matured
their designs
through
trade studies,
arriving
at low and high cross-range
orbiter
configurations
with a common
booster.
engines
provided
best
performance
configuration
to better
provide
Two
shown
in figure
The orbiters
and
abort capability
had hot-structure
lowest
but
later
and two main
gave
out. The baseline
engines
way
to the
Phase
B configurations
each.
three-engine
are
85.
Year
July 1970
RFP
September 1970
Requirements
See Table 26
• Revised Requirements
December 1970
Biotechnology
Integrated Electronics
Operations and Maintenance
Results
Cost in ($):
3,715,000
5,740,000
18,130,000
51,745,000
1,960,000
8,355,000
2,215,000
_. A-1
A. *MSC-Responsible
1.MAC-DAC and MM
2NAR and GD
A-2
15 x 30 Payload Bay
15 K
15 x 60 payload bay
LCR-46 K
HCR-20 K
2 Engines + Turbofans
2 Configurations
MAC-DAC--Orbiter
MM--Booster
2 Engines and Turbofans
2 Configurations
NAR--Orbiter
GD--Booster
B. MSFC--Alternate Space
Shuttle Concepts (ASSC)
1.Chrysler
2.Lockheed
3.Grumman/Boeing
May 1971
Results
- Payload 15-25 K
- Fuel (JP-4)
- Pressurized Payload Bay
• Technology Assessment
General Area of Concern:
Aerothermodynamics
Dynamics and Aeroelasticity
Propulsion
Structures/TPS and Materials
Contractors
cost
with engine
TPS's
• 1. SSTO
2. Stage and a Half
3. Stage and a Half
- External LH2 Tank
- 3 SSME's
- $6.7 Billion
(MSC)
* Lead Center Concept Developed
• MSC Integration of Shuttle Activities
• MSFC Responsible for Propulsion
Figure
84. Space
Shuttle
history--Phase
B.
177
Table
26.
Space
Shuttle
history--Phase
Phase B Program Requirements
B.
Requirements Leviedby Various NASACenters
Each element (orbiter and booster) shall have a two-man
flight crew and be flyable under emergency conditions
by a single crewman
The shuttle shall be a fully reusable two-stage vehicle
The integrated vehicle shall be launched vertically
and landed horizontally
The initial operational capacity shall be in late 1977
The stages shall be capable of positive separation without
the use of special separation rocket systems of the type
employed on Saturn
The reference mission shall be a 310-mile 55° inclination
circular orbit from a launch site located at 28.5 ° north
latitude (Kennedy Space Center)
In-flight refueling (subsonic or supersonic) shall not be
used to meet design mission requirements
The booster and orbiter shall be capable of pilotcontrolled landings under FAAcategory-2 conditions
The payloadbay shall have clear volume 15 ft in
diameter by 60 ft in length, with a reference mission
capacity of 15,000 Ib
Two orbiters shall be developed: one capable of 230 miles
and the other of 1,726 miles crossrange
The vehicle shall incorporate on-board provisions to
quickly and easily place the vehicle in a safe condition
following landing to permit crew and passenger egress
The mission duration (from lift-off to landing) shall be
7 days
There shall be no propellant cross-feed between elements
(booster and orbiter)
The booster and orbiter shall have a go-around capability
during landing operations (basically implying the use of
air-breathing engines)
The vehicle elements (booster and orbiter) shall be
capable of landing on runways no longer than 10,000 ft.
Launch rates will vary from 25 to 75 per yr
Total turn around time from landing to launch shall be
less than 2 weeks
Both elements shall provide a shirt sleeve environment
with trajectory load factors of less that 3G
A 43-hr turn-around capability shall be provided for
rescue missions
All subsystems, except primary structure and pressure
vessels, shall be designed to fail-operational after failure
of the most critical component, and to fail-safe for crew
survival after failure of the two most critical components.
While
a fully
reusable
two-stage
it became
apparent
that
expensive.
Peak-year
development
Shuttle
Chrysler,
external
178
concept
(ASSC)
Lockheed,
fuel-tank
concurrent
studies
and
concepts.
concept
funding
were
was
initiated
Grumman/Boeing
These
was
development
studies
the clear
choice
of
an
becoming
to look
studied
provided
both
for lowest
orbiter
a concern.
at alternatives
single-stage-to-orbit
the groundwork
operational
and
a booster
Addressing
this
to fully
issue,
reusable
(SSTO),
for future
cost
vehicle
would
alternate
two-stage
stage-and-a-half,
program
per flight,
decisions.
be
Space
concepts.
and
PH x_: LI
<
__LTiL<-'C.L_/
:'3
Orbiter:
Two 415K Engines
Four 18K Turbofans
Booster:
Two 415K Engines
Ten 18K Turbofans
in Canards
Orbiter:
Two 415K Engines
Four JTF22B-2
Booster:
Two 415K Engines
Four Turbofans
-.- u.-\X\
__. _-2..,:_--_L
:_:-::.:-::_"
\-\.. I_2
%.
- -'
_
._.
//
! ]_-
..............
.--_
......
f-
T--;
..............
""
Figure
6.1.4
STS Phase
The Phase
Shuttle
history--Phase
B baseline
configurations.
B'
In 1971, OMB
total NASA
85. Space
budget
informed
NASA
was $3.2B,
B fully reusable
no budget
increase
in the next 5 years.
with no more than $1B per year being
two-stage
of $2B in some
to expect
configurations
years.
The
allocated
a development
for ways to deal with the budget
limitations
Sacrificing
to obtain
lower
development
cost,
NASA
endorsed
tanks
outside
the orbiter
and also
used
expendable
B teams
by the addition
which
boosters.
The contractor
and Grumman/Boeing
requirements
groups
for using
B' configurations
6.1.5
STS Phase
"040"
are shown
in figure
(see table
recoverable
liquid
28). An extension
cost projections
was
provided
boosters
and solid boosters.
or in series
with the booster.
were added.
Total
development
boosters
would
unknowns.
In March
1972, NASA
entering
tanks,
and
three
main
their
of Lockheed
proposals
with
engines.
Examples
of
reduced
significantly
but were
still
booster
configurations,
86.
B', development
use of solid
orbiter,
external
were told to reevaluate
a
B"
too high
SRM's
and the teams
orbiter,
B, designated
(see table 27).
from the two Phase
studies,
the MSC
At the end of Phase
in parallel
the fuel
were expanded
from the ASSC
Phase
burn
cost in order
moved
of Phase
at an
cost
operational
an extension
peaking
B', to search
lowest
forced
development.
annual
of stage-and-a-half
constraints
to Shuttle
cost of S10B,
Phase
variation
budget
required
At that time, the
Phase
save
costs
$700M
to further
A major
were
C with a configuration
solid
study
issue was whether
In December
1971,
now estimated
in development
adopted
had been
although
boosters
basically
the orbiter
parallel
burn
at $5.8B.
NASA
carrying
more
to go with the external
similar
to today's
Shuttle,
including
main engines
was
adopted,
further
would
and abort
estimated
operational
costs
that
and
tank and three-engine
as shown
in figure
87.
179
Table
27.
Space
May/June 1971
Shuttle
history--Phase
Seplember 1971
• OMB informs NASA no budget
increase for 5 years
TSTO (_B) Shuttle development
cost $10B with peak of $2B
some years
Proposed total NASA budget
was $3.2B for 1972
Only $1 B/yr for srs
MSC considered external tanks
first time in their in-house studies
- 15 × 30 payload bay
- 20 K payload
- 4 engines
- Internal Ioxtank
Contractor teams expanded
to four:
- MAC-DACand MM
- NAR and GD
- Lockheed
- Grumman and Boeing
Requirement:
Reevaluateproposals
- MSC--040 Orbiter
- Externaltank
- Three high-pressure
chamber main engines
NASA endorses variation of stage
and a half (called semi-reusable)
- Some configurations developed
in 1965-1968 by Air Force
- Decreasein DDT&E cost
- Increase in OPScost
MSC studied 53 Orbiter
configurations during 1971-1973
Rebalancefor New Budget Constraints l::_
180
B'.
October1971
B'ended
_),_
PHASEB PRIME
NORTHAMERICANROCKWELL
Rear_ ew _'_
' .......
--
_
_
TopView
f_[---_-r_
_
PHASEB PRIME
MARTIN MARIETrA
\ ,"_---....
SideView
{
"/"/J';SingleTankeoncept'
_%RearView J
_
_lModified grurnman H-35
"_
I Orbiter and Bee,n0 e-2
....Top'op
ViewView
_b__.__..r..r._
I--- "_----_.
_:'_
-Front
""" >ew
Vt"
]L--
SideView
....
SolidRocketMotor_;(4}
*'"
_--
I_ Coaster
Derivative _\
,
\,_
I _
,¢RearView
Solid Rocket //'i-7-- ....
Motors(4) _
_
\\_
SideView
SideView
PHASEB PRIME
McDONNELLDOUGLAS
PHASEB PRIME
DualTankNotIllustrated
_lr-__
<._-_ %...._-_-_
LDC
si°e ;w
SideView _--_
RearView
Figure
86. Space
Table
Shuttle
history----example
28. Space
November 1971
Shuttle
December 1971
Phase 13' costs still too high
• $2.8M contracts to continue
- Grumman/Boeing
- Lockheed
Phase
history---Phase
B' configurations.
B'.
March 1972
Adopted parallel burn
Adopted solids
Added abort SRM's
- Cheaper development
- Faster
May-October
1973
MM and others TPS study
- Ablative versus reusable
- Tile technology
- But higher OPS cost
- More unknowns
- MAC-DAC/MM
- NAR
• New Ground Rule:
Stage below 4,100 mph
• Technical issues
- Booster configuration
• Fully recoverable, new liquid
engine, pressure fed
• Fully recoverable, based on
SIC stage
• Solid boosters
- Series burn/parallel
burn
• Separation dynamics
(favored series)
• Ground handling
(favored parallel}
• Main engine start on pad
(parallel)
• Cost analysis (favored parallel)
I
Desig,SignificantlY.!rn!_ac!ecl
!Y Budge!..,_
181
r-_
126.7 ft -.---_
[_"--L
_/'
I
t _ID
,_
I
'1_--'_--
b'l
OMS Engines (2)_
Auxiliary Liquid
Rocket Motor
Diameter
.Diameter
1
OMS Engines (2)_._.
,,o_s,./,,
-_._.
3=_8.1,
Ic&3%_11
\
_
Diameter._[-_
32 8 ft_
'*q_--'_--_
1-6°8.ft -I
_°-°"1
_'_'
--'------------,l_k
F --84"9ft-_1
T__L_
I I -_
[_,
[
--
182.3""
143ft
181,6ft
---.___
_
_
I"'-_!
L.j
I
__ 130,1823"
I
J
210.1 ft
McDONNELL
DOUGLAS/MARTIN
NORTH
MARIETTA
AMERICAN/ROCKWELL
LOCKHEED
GRUMMAN/BOEING
--
I-_
IS6-in. Diam_tRe;/_
128.1 ft _/Z
i
I
=
L__
I
/-
"r
_
!_f
92.5ft
_"_
13.5° Precant
/_
Abort SRM (2)
163ft
182
87. Space
OMS
_/-
Engines (2)
Abort
SRM(2/
j/,.J
Shuttle
62.1 ft 7
-50 4 ft 7
'_.
....
.q--z-r"
_
L,°,.,,
7::,S--J
_
138.2 ft
Figure
oPrecant
OMS Engines (2)
__.__1
, 1
Diameter SRB
r 60.8n 7 _q'CT___--Q---__C_Z_
_,
I_
128.1 ft --
[
,.. -1
history--example
Phase
B" configurations.
6.1.6
STS Phase
Table
29 shows
signed
for the development
design
phase,
Phase
workable
C
C, detail design,
the Shuttle
system
configurations
began
and
configuration
attain
involving
geometrical
and subsystem
functions
and
requirements/attributes
released.
Even
after the point
performance,
The following
elements
and for systems
integration.
a number
of design
performance.
structural
changes,
adding
the design
and operational
until
the
final
was frozen,
During
deleting
air-breathing
a
overall
engines
subsystems/design
vehicle
and balancing
detail
to achieve
six major
act between
production
tradeoffs
were
B'.
were
the 2-year
in order
There
and
of Phase
1973, contracts
modifications
(see fig. 88). The balancing
continued
at the end
In 1972 and
of system
and
observations
established
changes.
balance
evolution
where
configuration
configuration
underwent
the desired
SRM's,
a baseline
and major
of the Shuttle
and abort
requirements,
with
the main contractors
configuration
were
done
was
between
constraints.
are among the many
which
can be made
concerning
the development
history:
•
Political
decisions
the design
•
heavily
influenced
itself. This is common
Requirements
underwent
the development
for programs
major
changes
process.
Budgetary
constraints
drove
of this magnitude.
during
the process,
significantly
driven
by the above
considerations.
- The concept
of Phase C.
•
-
DOD
-
The continuous
started
requirements
The development
as fully reusable,
also drove
requirements
effort
but cost drove
configuration
the configuration.
flux demanded
was extensive,
and had large expenditures.
of variations
of vehicles were
-
contractors
participated
a continuous
spanned
community,
- Hundreds
Seventeen
to the stage-and-a-half
several
design
years,
balancing
involved
most
act
of the space
studied.
in 29 major
study
contracts
worth
$127M
issued
from
and large
in-house
activities
by
and interactivity
provided
design
1969 to 1973.
- There also was significant
NASA and the Air Force.
•
The complexity
challenges
which
funding
of the configuration
carried
for technology
groups
and its resulting
sensitivity
over into operational
complexities
and flight
constraints.
183
Table
Contractawards
Space
Shuttle
history--Phase
C.
Major ConfigurationChanges
Orbiter structural weight trades
(-1,000 Ibs)
August 1971
• SSME to Rocketdyne
(Contract signed
August 1972 after protest)
July 1972
• Orbiter to Rockwell, system
integration to Rockwell
August 1973
• Externaltank (ET) to Martin
• Solid rocket boosters
(SRB's) to USBI
• SRM'sto Thiokol
Requirements
• 65,000 Ibs due east
• 15' x 60' payload
• 1,265 mi cross range
29.
• Thrust structure, wing spar, drag
attachments, separate crew module,
composite bay doors, composite
OMS pods
See 1994 AIAA Propulsion Conference
Short Course on How Phase
B"/C Requirements Impacted SSME
Design16
Scenario of vehicle modifications
(see fig. 88)
"Vehicle r' (authority to proceed (ATP))
"Vehicle 2" (program readiness review
(PAR))
• Moved OMS Pods
• Forebody shape
• Orbiter/ET incidence
• Abort SRM's deleted
• Air-breathing engines deleted
• ETOgive nose
• SRB's shortened, moved aft
• SRBTVC added
"Vehicle 2A" (150K orbiter)
• Orbiter resized smaller
• Wing planform change
• Body reshape
• Air-breathing engines returned (ferry)
• Abort SRM provisions returned
• SRB's further shortened and moved aft
• ET shortened
"Vehicles 3 and 4" (mid-1973)
• Minor geometry adjustments for
aerodynamics and aerothermo
• ETshortened
• ETretrorocket (spike) removed
• SRM thrust termination dropped
"Vehicle 5" (early 1974)
• Modified OMS pods
• Abort SRM provisions dropped
• Added orbiter braking chute
"Vehicle 6" (production, mid-1974)
• Exposed RCS
• ETand SRBlengths changed slightly
• Umbilical door modifications
• Thermal glass on windows
IBalancing Act Continues Requirements/Design and System
184
_rc_----q
r["--1
e3
I.L
\
¢_
E
__8
1
77-
<i
l
!
-1
L
r
.----i
i_,
c 1L____I
J--/
/
J
=,t
or-,-
-_
_=0_
ivt
E_e-
Lr_
(1)
"0
'F
--
i'_-]
--
_.-, i i
/_
r_
I.!I
i
It1
N
8®,-_
._
.CI
..i_
I
_}
I
I_
'-1
_.
[--_'°__
t
z::_-
o
,1
,_
__ _._
O
I"
j
i
C
¢-
X
i y__2_l
I..
o._
[_..__,
1
J
Figure
88. Space
Shuttle
history---Phase
C configurations.
185
6.2
Design
In this section,
Process
for Flight
Mechanics
With
Loads
the complex
technical
integration
process
for flight
has been
accomplished
is illustrated
by describing
6.2.1
Space
Shuttle
The
Space
Table
30 shows
how this process
Flight
Shuttle
Mechanics
is used
a set of initial
simplify
the design
process.
bounded
by reentry
loads.
Technical
These
Some
example
developed
assumptions
of these
mechanics
and loads
modeling
for past programs.
for technical
during
cover
integration
the preliminary
topics
such
assumptions
proved
to be wrong,
ascent
crosswinds
would
not impact
design.
In order
to achieve
formed
initially
to handle
such topics
as aerodynamics,
loads,
Table 30. Space
Example
Integration
as the primary
assumptions
Modeling
Shuttle
design
as assuming
proper
of flight
mechanics.
phase
in order
that the ascent
such
integration,
loads
to
are
as the assumption
that
discipline
were
panels
etc.
preliminary
design.
PreliminaryDesign
Allocations
andassumptions
implemented
tosimplifythedesignprocess:
• Ascentloadsrequiredto bewithin re-entrythermaland aeroloads
• SRBnotdesignedbywaterimpactbutassessedby attrition
• Weightallocation:
- Elementdry weightandgeometry
- Vehicle"glow"
• S_BTI¥C
- FullTVC
- TrimTVCwith activeailerons
• Ascentcrosswindswouldnot impactdesign
- Consequences: 1. Highwingloads;wingfailed
2. Elementinterfaceloadssensitiveto
combinedaeroloadsascentaccelerations
Panelstermedtoenabletechnicalpenetrations
andcommunications:
• Panels:Aero,FlightMechanics,Loads,etc.
Going
groups
into the detail
were formed
ing Group
(AFSIG)
and sounding
design
phase,
problems
to aid the integration
groups
process
in integration
(table
and Propulsion
System
for the panels,
with recommending
The first major
tasks
Working
Program
defining
appropriate
parameter
various
disciplines
for each flight
tency
of the parameter
uncertainty
matrix,
assuring
design
but not overly
conservative.
Figure
90 is an excerpt
detail
of the parameter
uncertainty
matrix
is given
uncertainties
event
were
Group
authority
Shuttle
186
Manager.
Integration
started
to occur, and two major
31). The Ascent
Flight
(PSIG)
(fig. 89). AFSIG's
These
and methodologies
role was to assure
that the uncertainty
from
in the appendix.
Integration
uncertainties
levels
the parameter
were
were
uncertainty
Work-
as integrating
Manager
and
as well as
identified
completeness
chosen
working
Integration
were formed
to the System
to set up procedures
to use in design.
System
by the
and consissufficient
matrix.
for
More
Table
31.
Space
Shuttle
detail
design.
Detail Design
• Formed working groups
- AFSIG and PSIG
- Expandednumber of panels; integrated by AFSlGand PSIG
• First major task
- Set up procedures and methodologies
- Set up parameter uncertainty matrix by flight events
• Outputs of technical integration activities
- Impacts on vehicle design and sequence
• Parametercombinations for engine out; detuned wind gust and
engine-out by 6 seconds and all other uncertainties were 1_.
• Baselined lift-off dynamic analysis using 2c worst-on-worst approach.
• "A" factor andsquatcheloid approach baselinedfor max Q.
• 95% wind speedand 1/2 magnitude of shear and gust applied
deterministically; other half of the shear and gust used as uncertainty
with other parameters for max Q.
• Monthly meanwind biasing for design reference trajectory.
- Impacts on procedures and models
• DelayedSRB ignition
• SRB separation motor orientation, location, fuel combination, timing, and
number of motors.
• Necessaryload relief control increased thermal environments, increased
TPS, and reduced payload.
• Three axis load relief baselinedfor max Q.
CENTER
NAME
AFSIG REVIEW
DATE
MARSHALL
ORGANIZATIO_
SPACE
FLIGHT
SYSTEMS
DYNAMICS
LABORATORY
CHART
R.
NO.:
RYAN
APRIL
15
Parameter
1986
Matrix
Event
Discipline
Trajectory Performance
Pogo
Flutter
Control
Thermal
Liftoff Clearance (Drift)
Separation
Loads
Environments
Overpressure
Acoustic
Shock
Winds
IP
<¢
Prelaunch
Launch
Max Q
Max G
Pre-SRB Separation
Post-SRB Separation
SRB Separation
Second Stage Ascent
ET Pre-Separation
ET Separation
Total Ascent
Propulsion
Dynamics
Criteria
Failure Modes
Figure 89. Space Shuttle AFSIG---example
parameter
matrix event.
187
MARSHALL
ORGANIZATION
SYSTEMS
SPACE
FLIGHT
NAME
CENTER
DYNAMICS
R.
RYAN
LABORATORY
BASIC
CHART
PARAMETERS
DATE
NO.:
APRIL
16
Analysis Tolerance
SRM Propulsion
• TC227A-75
1986
Thrust Versus Time Curve Per SE-019-083-2H
(SRB System Data Book) for Bulk Grain Temperatures
(TC227H Is Proposed as Update)
ETR
WTR -- 81
52 °F
°F (Mean)/83.4
(Mean)/44.5 °F
°F(Max)
(Max)
• Flight-to-Flight Propellant Burning Rate
+ 5.3% (Two
_+4.7%
(One SRM's)
SRM)
• Thrust Level Development Uncertainty
+ 3%
• Thrust Oscillation (Dynamic Factor Assumed for
Loads Analysis)
+ 5%
• Steady-State Thrust Mismatch Between Motors
85,000 Ib (Ref. vol. X,
fig. 3.3.2.2e)
• Thrust Misalignment
+ 0.75 ° Per SRB
• Flight-to-Flight Thrust Level Dispersion
+
4.9%Single
Both Motor
Motors
_+5%
Aerodynamics
• Pressure Distribution Test Data Match with Aerodynamic
Coefficient Test Data
+ 3%
• Elevon Deflection Schedule #6 (Hinge Moment Limiting
Feedback) Per Rockwell Internal Letters ACDA/FSA/76-527
and 531
_e O= f (ACHM = 0.02) Aero
Data Adjusted to New
(SeO+ _Seo)
° SD72-SH-O060-2
None
(Mated Vehicle Aero Design Data Book)
• Include Aerodynamic Tolerance Effects on Coefficients: Wind
Tunnel Deviations Plus Power-on Deviations Plus Reynolds
Number Effects
Figure 90. Space
188
Shuttle
AFSIG--example
Values Per PRCB Briefing on
8/18/'76 MCR 3378 "5.3 Ascent Load
Adjustments"
parameter
variations.
Many
Impacts
impacts
that were
to the design
too severe
used in the design
process.
characteristics
of a vehicle
changes
made
by AFSIG
Vehicle
operational
SRM ignition
tion,
were resolved
by changing
31 lists
of uncertainties
to reduce
impacts
were made
ignition
in order
dynamic
Three-axis
load
Table
32 delineates
other
the safety
on the external
100 to 109 percent,
design
factor
introducing
risk mitigation
SSME
improvements.
and maintain
procedural
a highly
on loads,
to capture
a minimum
relief
another
was
application
were
and criteria
reliable
system.
etc. For example,
stored
addition.
energy
These
the
condichanges
in a loss of performance.
problems
Certain
of these
of uncertainties
5 sec after SSME
loads.
was too severe
a number
the effect
but resulted
particular
for the high performance
on worst
Table
loads
(i.e., reducing
and their
of worst
Shuttle.
were implemented.
how the uncertainties
like Space
changes
lift-off
due to how the parameters/uncertainties
The prior approach
to minimize
was delayed
thus reducing
reduced
occurred
changes
the high
that
were
Table
made
tank from
SRM,
Tile Team,
performed
32. Space
to reduce
weight/increase
1.4 to 1.25, increasing
performance
such as the Orbiter
activities
were
such
etc.).
SSME
as the mated
Shuttle
change
the SSME
Special
Design
performance
teams
Team,
vehicle
thrust level from
were
formed
to solve
and SRB Recovery
ground-vibration
Team.
test and
examples.
DetailDesign
• Other tasks
-ET 1.25 ES.
- All welded SSME
- HPM/SRM
- Orbiter improvements
- 109% SSME
Planned performance evolution
nhancements after first flight
• Special teams
- Orbiter tile team
- SSME team
- SRB recovery team
• Risk mitigation activities
- Mated vertical ground vibration tests
- Engine improvements
Even
wing
with all these
special
activities,
and on the interface
members
between
and the SRB's.
The program
(see table 33). In order
to launch
(LSEAT)
was formed
system
evolved,
day-of-launch
to launch.
Many
flight
test program
such
added
performance,
etc.
safely
I-load
as water
such as loss of load margins
and external
test phase,
margins,
day-of-launch
wind
updates
changes
troughs
were
were
employed
implemented
for overpressure
tank and between
so operational
with these lower
to perform
design
occurred
the orbiter
was now in the flight
Team
2 hr prior
problems
which
reduction,
System
utilize
super
uncovered
light weight
tank
sought
Advisory
constraints.
the measured
problems
were
Evaluation
with specific
to reduce
the external
work-arounds
the Launch
monitoring
on the orbiter
As the
wind
profile
early
in the
tank (SLWT)
for
189
Table
33.
Space
Shuttle
change
examples--test
and
operations.
FlightTestand Operations
• Changesrequired*
- Organized LSEAT
- Day of launch monitoring/launch constraints
I Balloon flight day of launch/realtime flight assessment
- Day of launch I-loads update
- Special instrumentation for SRBAFT skirt
- ETTPS (Ice team)
- Engine operations procedures; engine redesigns
- RedesignedAFTskirt due to water impact
- Two changes in SRB parachutes
- Changedhow orbiter tiles were attached
- Debris/tile team
- SSME 104% versus 109%
- SRM overpressure accommodations
- Changesto meet EPA regulations
-- ETTPS
- RSRM
- SLW-r
Two Duct HGM
Damping seals
Single crystal turbine blades
Large throat nozzle
Silicon nitride bearings
P and W high pressure turbo pumps
* This list is representative; not all inclusive.
6.2.2
Loads
The
natural
Modeling
basic
Example
process,
environments
figure
with
91,
their
models
the
uncertainties.
vehicle)
with
its uncertainties
these
together
produces
probabilistic
level
What
is needed
margins.
Achieving
this
approach,
and
the
design.
The
produces
the
basic
ideal
performance.
variations,
in order
to secure
analysis
efficiency,
specialized
reference
trajectories
become
the basis
for analyses
using
the
responses
outputs
perturbation
of
are
the
from
used
requires
process
that
the nominal
to have
considerable
as inputs
responses
response
(the
Combining
variations.
These
is for the
plant
work
trajectory
with
the
input
starts
with
the
generation
Since
the
ideal
cannot
to generate
become
an assured
loads
acting
for
loads.
the
trajectory,
because
to determine
as well
as the
dynamic
The
(see
sketch
elastic-body
Plant
Characteristics
andUncertainties
9 I. Overall
concept
for flight
with
the uncertainty
reached
on the vehicle
inputs
as the
to produce
trajectories
uncertainties
Natural
Environments
andUncertainties
190
of
be
reference
the
Parameter
Matrix and
Uncertainties
Figure
variables,
as well
a response
are
combination
figure
92,
of
effects
93).
shows
The
this
response.
Response
Variations
_. /
I
mechanics.
the
generated.
perturbated
fig.
adequate
*Assured on a
_
ProbabilisUcLevel
which
of
These
responses.
figure
shows
wind-induced
StepI
Ideal Optimized
Trajectory
(Response)
Step 2
Reference
Trajectory/
Trajectories
Step 3
NonIdeal
Perturbed
Response
(Uncertainties)
- Ideal OptimizedTrajecloryand
PotenlialPayloadMargins
- Inputto Slep 2
- SpecializedTrajectoriesGeneraledto
AchieveAnalysisEfficiency
- ReferenceTrajectoryInputto Step3
- 3c Response
Note: Steps2 and 3 Performedfor andTailoredto EachMission Phase
as Well as for Special Situations
Figure
92. Method
to achieve
J_3/
//.,,"T'_/,_
"/"//_
• Rotational Acceleration
_.,.7.,- _,v_-/.-L_'_-,_
• TranslationalAcceleration
//V._//
Gimbal Angle and Rates
,, _ .f"/_".,_"_
.. _
CG offset
o_'_,'_-"_._ J/_/
_
Thrust
<_'/
/
//
Aero Loads,
_
f//
/
Moments, and
9\ f''-'-'''_
/
/
Distribution
/'
_"'__
_
performance
goal.
_
."
-_='
_
_
/
/ _
/
/2_
" /
/
/
I
_/
Reference
Trajectory To
Orbit
:
:
_
Target
/ /" _
"_ \ " Location
[ I { • ) ) ] "Payload
t\ _\ "v///
/;
ano\ _
J
/
.
•
_
Margin
Natural Environment
,
_
_
._ t:_: y and Directi°n
JData Requirements for Load Analysis k
i
Figure
93. Illustration
i in
n,,,
of design
...........
,,,
,
process:
,:
.....
structural
loads.
191
To achievethe mostconservativedesign,ideally one would want to designfor the comersof
parameteruncertaintiesspace,asshownin figure 94; however,this is generallynot practicalbecauseof
performanceimpacts.The next mostdesiredapproachis to accomplisha purestatisticalanalysissuchas
Monte Carlo of the vehicleparametersand the naturalenvironments.This hasnot beenpractical until
recent years and is still costly. Therefore, the synthetic wind model was developed along with a
root-sum-square(RSS) and A-Factor approachfor uncertainties(see table 34). The approachis a
conditional probability approachwhich says that given the 95 percent wind speedcombinedwith
99 percentshearand gust effectsRSS'd,the load mustbe maintainedwithin the 3-sigmabound.This
approachwasvery efficientfor SaturnApollo andhasbeenvalidatedby a Monte Carlo analysis.
IiParamee
ii [,,ems
Mean and
Uncerlainties
>
Model
(Plant)
Parameter
Design
Outputs
I
t
I "a'"r"'
I
Environments
-- Ideally the desire is to design for the corners of the box such thatthe inputparameters and the
plant are good for the extremes. This results in overly conservative loads.
Figure
loads
illustration.
approach
during
design
(see table 34). Other than the wind model
change,
the same conditional
The Space
wind model
was
used.
Figure
approach
192
saved
followed
model
change
how the approach
and q-beta
number
squatcheloid,
used
wind
95 shows
q-alpha
Mach
The
Shuttle
plots as a function
produces
time
a loads
consistent
significant
only 2-sigma
variations
94. Structural
a similar
was
introduced
was applied
of Mach
envelope
instead
to different
number.
velocities,
conservatism
load parameters
Combining
tube as a function
accelerations,
amounts
to remove
with some
and
of 3-sigma
(table
35).
trajectory
positions
time. The X-33
called
patterned
changes
probabilistic
without
the squatcheloids
of ascent
of computer
significant
in the
approach
impacting
squatcheloids
safety.
that are
as a time function
of
time. At each point on the
are used
for load
their approach
analysis.
This
after Shuttle
but
Table34. Structuralloadsillustration.
• The desire is an all up Monte Carlo of the vehicle parameters and the natural environment parameters.
In the past and to some extent in the present, this was not possible or, if possible, not design analysis
efficient. As a result alternate procedures were developed.
• Saturn Apollo/Skylab
Saturn used a conditional probabilistic approach, where a synthetic deterministic wind profile is the
condition. The vehicle's response is determined to this profile using the mean and the 3G parameter
uncertainties (individually) producing a set of responses which can be root sum squared then multiplied
by a factor of three producing: 3,_ response against the condition (winds).
-Wind model (deterministic) (the synthetic wind profile model was generated for each critical
altitude/match number)
• 95% worst month scalar wind speed
• 99% worst month wind shear and gust (due to the conservatism, the shear and gust
were RSS'd)
- Plant models (Two)
• Rigid body with and without propellant sloshing dynamics
• Rigid plus elastic body with propellant sloshing dynamics
- Parameter uncertainties
• 3,_ about mean
• Normal distribution assumed
- Analysis approach
• Run response to synthetic wind profile (one altitude) using mean of parameters
• Run response to synthetic wind profile (same altitude) using mean of all parameters but one,
which is the +1_ level
• Repeatfor-l_ level of parameter
• Repeat process for + and - of each individual parameter
• RSSfor each response, develop a single time response run which produces a time consistent
response that produces the same 3c peak. (Time consistent set of response data required
for balanced load set.)
• Repeat process for each critical altitude/Mach Number
• Produce conditional probability set of design data
• Engine out phased with wind gust
- Operations
• Bias trajectory to monthly meanwind to obtain margins.
- Validation of synthetic wind approach was made using individual measured wind profiles (50m
wave length, 150 profiles per month) in conjunction with Monte Carlo approach. (Winds only,
vehicle parameters nominal.) Good correlation with synthetic profile.
• Space Shuttle
- Space Shuttle used the conditional probabilistic approach; however,the wind profile model was
changed. (Remove conservatism)
- Winds model (synthetic profile; looked at using directional speed change).
• Trajectory biased to monthly mean wind (design)
• Synthetic profile directional
- 95% worst month wind speed
- 50% of 99% shear and gust magnitude RSS'd.
• 50% of 99% shear and gust treated as uncertainties along with all other vehicle parameters.
- Winds model (Individual profiles)
• Monthly detailed wind profile (50m wave length) 150 per month (special studies)
- Analysis approach
• Same conditional probability approach aswas used for Saturn except using squatcheloid
as output. (See fig. 95)
• Simultaneous pitch and yaw synthetic wind profiles required
• Engine out delayed 6 seconds past gust peak. 1_ vehicle parameter uncertainties, used with
engine out
• Bending dynamics response accounted for by multiplying rigid body loads by 10% (conservative
based on special studies). Liftoff and landing analysis made using bending dynamic models.
• Liftoff used 2c worst-on-worst parameter uncertainty method
193
qO_
Nominal vehicle parameters, synthetic
profile 95% speed, 50% shear, and gust
RSS'd, one specific Mach Number,*
mean wind, and reference trajectory.
3_ vehicle parameters, 50% shear and
gust synthetic wind profile, mean wind,
and reference trajectory
X
Example
Range
A-Factor approach used to generate time
consistent accelerations, gimbal angle, and
angle-of-attack data for loads.
of
qc_
* Process repeated for each Mach number
Range
Mean
0.6
of
qP
Trajectory
_nd
I
!
!
I
1.0
1.4
1.8
2.2
Machnumber.
Flightenvelopeby useof squatcheloid
Figure
95.
Structural
Table
loads
35.
illustration--squatcheloid
Structural
loads
approach
illustration--X-33.
• X-33
- X-33 usedthe conditional probability approach for max "Q";same as Shuttle for lift off
- Monthly mean wind biasing
- 2c parameter variations
- Wind model
• Synthetic profile
- Analysis approach
• Squatcheloid approach as was used for shuttle
194
for loads.
Table
process
required,
36 is a summary
was provided,
the lessons
and this analysis
to establishing
accurate,
of lessons
are applicable
complicates
efficient
Table
learned
to all the various
the design
approaches
36. Structural
this example.
process.
design
Creativity
for the specific
loads
Although
vehicle
only
activities.
a snapshot
of the loads
Uncertainty
analysis
and innovation
being
of engineers
is
are keys
designed.
illustration--summary.
DesignProcessfor FlightMechanics
withLoadsModelingExample
• Uncertaintyanalysiskeyto a reliabledesign
• Uncertaintysignificantlycomplicatesthe designprocess;loadanalysisusedasexample;
establishedandverified
• Similaruncertaintyanalyseswerealsousedfor all otherdesignfunctions
• Creativityand innovationof engineerskeyto establishingaccurate,efficientdesignprocess.
195
7. EXPERIENCE-BASED
7.1
A survey
essence
was conducted
of engineering
clear and succinct
The
statements
7.1.1
James
Survey
design
lessons.
of Experienced
of experienced
based
practitioners
without
(Retired
NASA,
"In a vehicle
system,
all parts are connected;
organization
organization,
presently
acknowledges
and especially
in Aerospace
in aerospace
have been collected
and provided
Blair
design
Practitioners
using the question,
on your many years of experience.'?" Many have
Their responses
are unaltered
KNOWLEDGE
the individual
is the
with very
by their individual
names.
comment.
at University
this
and are included
"What
responded
of Alabama
a change
system
in Huntsville)
in one affects
connectivity,
engineers'
the others. The more fully the
by means
perspective,
of communications,
the more successful
will be the
design."
7.1.2
Bob Brotherton
(Former
En_lneerm_
is logical."
'¢
7.1.3
O'"
Jack
O"
Bunting
"Test
7.1.4
"
McDonnell
(Lockheed
Martin,
Douglas,
presently
with Boeing)
Denver)
what you fly, and fly what you test."
W. E. Campbell
"Success
(Retired
Aerojet)
lies in attention
to detail,
with a methodical
top-down
approach
to identify
the areas of
concentration."
"One-fourth
to one-half
hardware,
process
producibility
of historical
escapes,
in favor
and
rocket
engine
like.
One
the
of performance,
management
"Stacking
worst-on-worst
tolerance
(or schedules,
untenable,
noncompetitive
design,
product,
toward
a competitive
these
but successful
probable
seen to be attributable
contributor
and envelope.
technical
point
to balance
weight,
failures
to out-of-print
is insufficient
priority
on
It must be the mandate
of project
and
etc.) results
is an
approach
will
priorities."
costs, contingencies,
or program.
Some form
margins,
of probabilistic
solution."
"Project
scheduling
should include
small enough
task increments
that an event "miss" can be
recovered
with reasonable
downstream
workarounds.
Last minute surprises on long-span tasks are
project
196
disasters."
"Nearly everythingin theworld hasadistribution.A simplifiedprobabilisticapproach(which does
not becomefrustratedby imprecisealgorithmsor incompletedatabases)is an excellenttool to
identify drivers,screenoptions,andevaluatesensitivities."
"A part fracturefailure occurswhen "stress"(in someform) exceeds"strength"(in someform).
This can be the starting assumption
for failure
analysis,
which must identify
and rectify
the
combination
of higher
elements--both
7.1.5
(than
of these
manufacturing
processes,
Chris
(NASA
Chamis
"Simplicity
solutions
"Major
hurdle
stress
including
the
part history,
Lewis
in formulations
"Simple
expected)
elements
effects
(than
conditions
resulted
expected)
and
strength
environment,
in failure."
Center)
wins over complexity
in simplicity
lower
of operating
and the like--that
Research
to engineering
and/or
problems
is resistance
in every respect--succinctly
require
insight
that is gained
from inexperienced
colleagues
require
management
better-faster-cheaper."
by experience
and maturity."
and not very knowledgeable
supervisors."
"Simple
solutions
other required
"Successful
pounding'
7.1.6
engineering
Christensen
"One
good test is worth
(Lockheed
analysis
Christie
a thousand
to always
person
which
'The
nail that sticks
is the current
power
and
out gets the
practice."
Huntsville)
opinions."
Paralysis."
do an analysis
before
the accuracy
testing.
It is equally
of the assumptions
important
to conduct
of each system
For example,
polysulphide
sealing
system.
It also minimizes
in an aerospace
design
in pressurized
commercial
The sealant
adds weight
the bleed
air requirements
affects
aircraft
at least
in the analysis."
design knowledge
must be combined
with an understanding
process in order to achieve the most successful
design."
performance
resistance
on the proverbs:
gets the grease,'
Design
to confirm
in the design.
joints.
support:
Seattle)
one valid test in order
"The
continuing
are not based
Martin,
can cause
(Boeing
"It is important
"Engineering
manufacturing
solutions
wheel that squeaks
David
Peter
problems
resources."
or 'The
"Too much
7.1.7
to complex
of materials
the performance
of other
and
systems
fuselage,
all joints
are sealed
and cost and affects
the fatigue
life of structural
increasing
the corrosion
of the engine,
while
with a
of the joint."
197
7.1.8
Werner
Dahm
(NASA
"Mother
Nature
"Paper
is patient.
"As your design
"The chief
glory
MSFC
Sense
or nonsense,
proceeds,
weights
decision
maker
"If you aim for about
Their quest
for personal
will be good.
possible
performance,
If you aim for more,
your
Inc.)
isn't
very useful
without
a simple
to guide
interpretation
fame and
the designer
(NASA
and
Aerospace
Consultant)
"In a system
design,
no change
any change
no matter
how good it sounds
the system
and every
other
will stay
and risk will
of the FW 190
of late WWII.)
(Retired
model
model
and provide
checks."
Jim French
Philip
costs
your costs
with InDyne,
Glynn
(Retired
takes place
change
has system
in isolation,
in isolation.
must be reviewed
NASA,
presently
is the process
"Engineering
in terms
Boeing
Station)
of creating,
uses the laws of physics
evaluating,
is a state of satisfaction
pain of attention
to the details."
Micheal
Griffin
(Orbital
"Look
aggressively.
"Don't
shoot the messenger.
Sciences
The absence
Space
and assuring performance
and mathematics
of life on earth. As such it is the enabling
excellence
Every
level effects
of its impact
and
upon
subsystem."
"Engineering
need."
"Engineering
198
hounds.
presently
Dioron
proverb.)
do so."
NASA,
Harold
quality
man."
7,1.12
is an old German
to me by Hans Multhopp,
plane
sanity
7.1.11
(This
go up."
of the theoretically
of success
her way, she lets us fall."
all we write."
steer clear of the glory
80 percent
(This caveat
follow
was passed
fighter
"A complex
7.1.10
always
should
Scientist)
If we don't
it accepts
and will always
and your chance
grow exponentially."
7,1.9
Aerodynamic
does not read our paper.
has cost us dearly
moderate
Chief
to expand
environment
known
of any defined
man's
horizons
and improve
the
to improve
man's
relationship
with
which
has endured
the
only to the group
Corporation)
of a symptom
Messages,
does not imply the absence
but not problems,
human
will cease
of a problem."
arriving."
7.1.13
Ron Harris
"Arrive
7.1.14
(Retired
NASA,
at a decision,
John
L. Junkins
"Cooperate
almost
(George
"Keep
simplifying
Texas
every
questions
immediately
when
to propose
solution
Dick
(Retired
NASA,
energy
solutions
are
Know
and challenge
Then
convene
Administrator,
to be on orbit and be criticized
for not being
of management."
try to define
intelligence,
corresponding
but thank God
for the
in the same person."
who your best engineers
arise,
communication
a composer."
the question."
trump world-class
strategies.
Associate
himself
and simultaneously
questions
is 95 percent
ground and be criticized
several
are, seek them out
proven
individuals
(not
a
the committee."
presently
and 5 percent
for not having
with Kistler)
engineering."
enough
capability,
in orbit.' This is what J.R. Thompson
than to be on the
preached
to me during
Station."
"Consistency
Wayne
is the work
Littles
(Retired
engineering
with
"Capable
discipline
technicians
elements
in producing
program
success
John McCarty
but we must be consistent."
Associate
and Whitney)
manufacturing
of dull minds,
NASA,
with Pratt
"Proper
minimum
with five levels
when you find both attributes
the tough
Integration
thinks
tests that answer
will usually
committee)
Space
possible,
musician
best advice I can give to a project manager:
Kohrs
American)
A&M)
extent
but not very likely
and experimental
determination
"It is better
7.1.17
when
the most important
that can be performed
"Systems
7.1.16
Maybe,
computational,
"World-class
7.1.15
Chair,
to the maximum
an orchestra
Better, Cheaper?
"The
J. Eppright
Nature
"Faster,
miracles
North
the most reliable."
"It is hard to conduct
analytical,
with Boeing
don't rush into them."
with Mother
always
presently
and software
Administrator,
the products
developers,
quality flight hardware
are sound
(Retired
use of dispersions,
Systems
NASA,
tolerances,
accurately
Director,
presently
transmitted
to well
trained
along with a thorough test program, are necessary
and software,
Engineering
presently
MSFC
but the essential
and effective
ingredients
to ensure
communications."
a consultant)
in analysis
and test is key to propulsion
system
design."
199
"A high quality
"Failures
7.1.18
are when
price of any design
Dale
Myers
(Retired
it simple
"If it isn't
7.1.20
NASA
because
Deputy
doing
at all, it isn't
worth
(Retired
attacking
a problem,
remember
Joyce
Neighbors
(Retired
NASA,
Career
path in engineering:
and technical
products."
with
of new failure
causes."
Kistler)
well."
wine."
that things
usually
presently
systems
"Understand
design
Larry
Pinson
(Retired
NASA)
"'All the easy
problems
have
managers,
for becoming
learn how other disciplines
stay grounded
in your
an engineering
or program
requirements
specialty;
manager
for the life of the product
analysis
to be."
Martin)
in some discipline,
but
and test to corroborate
been
are truly as they appear
Lockheed
a specialist
and prioritize
during
with
engineering
qualification
cycle. Analyze
before
early
putting
product
structure
while people
this gives
for high
in design
into operations."
solved.'"
we like to focus on formal
management
motivation
is the real issue."
"If people
Robert
are sold on a project
S. Ryan
"The higher
environments,
"Political
(Retired
outcome,
NASA,
formal
presently
organization
shapes
(Mother
a project
Nature)
to her or you fall down."
as much
of the problem
is nearly
irrelevant."
a consultant)
the performance
requirements,
the greater
design, manufacturing,
etc. Performance
viability
"The Physic
down
presently
without
"First become
Learn
technology
usually
is the introduction
NASA)
experience
success:
doing
is like a dinner
"When
with yours.
work."
Administrator,
Program).
reserve
really
it is a change,
(The KISS
without
"As engineering
200
change,
how things
Morris
Mission
7.1.22
learn
Owen
interact
7.1.21
is one that has high reliability."
stupid"
worth
"A program
system
engineers
"The
"Keep
7.1.19
propulsion
the sensitivity
requirements
(nonlinear)
to variations
drive the design."
in
as engineering."
reigns
supreme
(The God of Design).
Either
you bow
"All design
is a paradox,
a balancing
act. Understanding
sensitivities,
interactions,
is the key to
and loading
conditions.
SUCCESS."
7.1.23 Lucien
"The
A. Schmit,
en_,meer
Jr. (Retired
s main
O. °
task
If we are not imaginative,
"The
value
Professor,
University
is to anticipate
nature
of California)
possible
will punch
failure
modes
a hole right through
of simple
limiting
cases
"Behavior
sensitivity
analysis
and
obtaining
quantitative
answers
to 'what
if' questions
(Retired
NASA,
presently
our design."
as test problems
for assessing
computer
optimum
sensitivity
analysis
traditionally
asked
codes
cannot
be over
estimated."
7.1.24 Luke
Schutzenhofer
"Skillful
leaders
communicate
consider
all ideas,
encourage
"Focus
on working
"Better
can be the enemy
7.1.25 David
Sisk
"In designing
the goal and
debate,
at University
objectives,
and discourage
the right problems
(Lockheed
design
are powerful
for
by designers."
of Alabama
reward
tools
creativity
in Huntsville)
and good
work
ethics,
the fear of failure."
right."
of good."
Martin,
any structure,
Huntsville)
start with and continuously
focus
on the joints.
If you get the joints
right, the rest will fall into place."
7.1.26
Parker
S. Stafford
"The design,
development,
in mind;
i.e., systems
hardware,
software,
"Flight
7.1.27
(Retired
software
Martin
and test of a system
tests should
and ground
should
Marietta,
duplicate
systems
be validated
should be done with the mission
operations
objectives
real
sequences.
Use
wherever
in a realistic
is functionally
equivalent
to the actual
all planned
and contingency
uplinks
"Analysis
data used
to define
Consultant)
mission
operations
and
flight
possible."
mission
environment.
dynamic
This should
simulation
include
environment
the initial
which
flight load and
to the spacecraft."
qualification
configuration
managed
as released
John Thomas
(Retired
NASA
"Any
endeavor
without
understandable,
enjoy
success."
tests,
operating
ranges
and tolerances,
etc.,
should
be
engineering."
and Lockheed
Martin)
achievable
objectives
and well thought
out plan will not
201
7.2
7.2.1 J.E. Gordon
Strong
(Author
Materials
"All structures
7.2.2
Design
of Structures,
will be broken
of medicine
is: What
is to be regarded
Horn
and engineering
(Deceased,
"If you can't
explain
"You cannot
be a good
Henry
Petroski
is Human:
to postpone
interval?"
NASA
V-2
and
it with a simple
system
(Professor
"Every
solution
of every
obviate
failure
in all its potential
design
is made
"Lessons
are best learned
failures,
not only within
unless
"Concept
7.2.5
David
(Author
selection
best concept
Science
of
to a system,
Pye (Author
be saved
interval;
the question
engineer)
understand
you have penetrated
Duke
Design
begins,
it."
one discipline
University,
16 and Design
no matter
the whole
and
author
Paradigms:
how tacitly,
we are familiar
system
in depth."
of To Engineer
Case Histories
with a conception
similar
of
of how to
to that change."
of textbook
case studies
it, so that when we do make
might
be wrong
analogous
in our reasoning
of past
errors
and that we
3)
done can never be righted
(realized)
of The Nature
must adjust
with a wide variety
our own field but also outside
improperly
for a decent
manifestations."
of Total Design
selection
will die in the end. It is the
17)
problem
when
rocket
you don't
in Successful
in Engineering
change
these occurrences
of Civil Engineering,
and Judgment
Pugh
Fall Down s and The New
Ryan
analog,
engineer
Error
Stuart
Don't
German
by Robert
we get a nagging
feeling that something
should double check our work."
7.2.4
References
in the end. Just as all people
as a decent
The Role of Failure
"If any small
Selected
or Why Things
or destroyed
Provided
7.2.3
From
Is)
purpose
Helmut
Suggestions
with the best engineering.
Neither
can the
using poor engineering."
of Design
6)
"When you put energy into a system you can never choose what kind of changes shall take place
and what kind of results remain...
All you can do, and that only within limits, is to regulate the
amounts
202
of the various
changes.
This you do by design."
7.3
The combined
aerospace
workers,
integration
experience
of launch
vehicle
or applying
7.3.1
Lessons
Specific
1. Although
Learned
of the authors in conjunction
and the referenced
accomplishing
Lessons
literature
design.
Each
with this activity,
have resulted
lesson
learned
are essential,
people
in a series
has
a subset
the survey
of lessons
of experienced
learned
of attributes
for technical
and/or
tasks
for
the lesson.
Learned
engineering
skills
skills are mandatory
for achieving
successful
who listens and encourages
everybody
products.
- Choose
a strong
leader with decision-making
capability
to integrate.
- Organization
is a tool to accomplish
the organization
is secondary.
Provide
a reward
system
missions
and objectives.
Encourage
engineers
the job; however,
with proper leadership
the alignment
of roles and responsibilities
to encourage
to enhance
their cooperative
interactive
and motivation,
with project
skills as well as their technical
skills.
Train
engineers
Reward
to be specialists
specialists
with a systems
who participate
focus.
in integration
activities
in order to formulate
a world
view
of the total system.
- Provide
2. Manage
an open environment
which
to ensure good technical
- Technical
encourages
innovation
is crucial to the design process.
and assess
that it is being
is the key, predominant
- Most integration
communication
the physics
Make every effort to encourage
technical
done.
- Communication
- Understand
communication.
integration.
integration
integration
and stimulates
part of technical
is informal,
both within
integration.
and between
planes.
of interaction.
Continuously
check
requirements
Continuously
check
assumptions.
Proper compartmentalization
flow.
(subsystems/design
functions/disciplines)
facilitates
integration.
203
Working
Focus
groups
people
Integration
3. Manage
can enhance
skills toward
proper
- The right concept
concept
integration.
integration.
is everyone's
to ensure
technical
responsibility,
concept
selection
but
leadership
must
The best detailed
design
ensure
technical
integration.
selection.
is critical.
will not correct
a flawed
selection.
- Put sufficient
- Ensure
effort
into front-end
that options
of concepts
engineering
are fully explored,
(quality
lever).
converging
with successive
only after appropriate
convergence
of the various
must assess
validity
refinement
(greater
detail)
and requirements.
- Pick a concept
concepts;
i.e., do not eureka
the concept.
- In early
phases,
discipline
specialists
depend
on sizing
program
alone.
- Avoid
concepts
4. Requirements,
having
too many
constraints,
External/political
low-level
and criteria
considerations
of sizing
program
results.
Do not
(for example,
Space
TRL's.
greatly
influence
and constraints
design.
strongly
drive
design
Shuttle).
Technical
constraints
Analyze
and challenge
possible
engineering
Do not accept
requirements,
design
unrealistic
defined
and vacillating
wasted
design
effort
criteria
suppress
must be tailored
5. All design
is a balancing
with some
constraints,
them
carefully
and criteria
and judiciously.
at all levels
to obtain
the greatest
and budgets.
top-level
and compromised
- Criteria
so apply
flexibility.
schedules
Poorly
Overspecified
204
also drive the design,
requirements
the creativity
for the specific
act between
of what you do not want.
cost the program
dearly
in terms
of
design.
of the design
engineer.
project.
conflicting
requirements.
You get some
of what you want
- Balancingmustoccuramongdisciplines(energyredistribution).
- Balancingmustoccuramongprogramrequirements,thedesign,andoperatingplans.
- Cost,risk, andperformancearelinked attributes.An improvementin oneattributetypically
producesa detrimentin another.
- The balancingactrequiresopencommunicationandkey decisionjudgments.
Assessingrisks versusconsequences
is a key ingredientof thejudgmentprocess.
- Problemswhichcannotbecuredin designmustbecompensated
for in operationalcompromises
andconstraints(e.g.,mayleadto reducedprobability of launch).
All designsmustachievemarginsor probabilitiesacceptablefor safetywhile maintaining
performance.
6. Considerationof systemsensitivitiesanduncertaintiesis crucial to designprocess.
- Successfuldesignrequiresthat sensitivitiesanduncertaintiesbe properlyaccountedfor and
managed.
- Uncertaintysignificantlycomplicatesthedesignprocess.Incorporateappropriatephilosophy
andproceduresfor handlinguncertaintythroughouttheprocess.
- Systemsensitivities(bothwithin andbetweendesignfunctions)areindicatorsof how much
concernshouldbegivento uncertainties.
- High performancesystemshavehighsensitivities,requiringmoreattentionto detailsof design.
- Designmusteitherreducesensitivitiesanduncertaintyor provideadditionalmargin.
- In theearlystagesofdesign,ensurethatadequate
marginsareprovidedtocoverthesensitivities
anduncertaintiesof the specificvehicle,consideringits coarsestateof definition.
7. En_,meers
judgment
a"
and creativity
is essential
to design
process.
- The complexity
launch vehicle
of the system requires applying judgment
and innovation
to the specific
situation. This cannot be supplanted
by dogma, rules, or recipe.
- Tools
efficiency
enhance
- Guidelines
approach
- Many
system
and criteria
which
decision
but cannot
replace
should be tailored
unnecessarily
constrains
gates are not deterministic
knowledge,
the judgment
or adapted
design
and creativity
to the particular
of the human
mind.
project
to avoid
a dogmatic
requiring
indepth
discipline,
solutions.
but are judgment
based,
and wisdom.
205
- The levelof penetration
design
stage,
8. The design
is an engineering
sensitivity,
process
Continually
determined
by project
improve
it wherever
possible.
characteristics,
and uncertainty.
is complex
explore
judgment,
and laborious;
approaches
to high-leverage
improvements,
both evolutionary
and
revolutionary.
Reduce
process
fragmentation;
- Improve
design
modeling,
Explore
more
direct
move
especially
synthesis
toward
more
for cost,
operations,
approaches
seamless
to better
design.
and reliability.
convert
requirements
to concepts
and
fidelity
repre-
designs.
Improve the conceptual
sentations.
Develop
and mature
sary design
7.3.2
Associated
Lesson
as the engineering
Whether
it is 90 or 60 percent,
by requiring
the discipline
must support
this emphasis.
system
better
synthesis
for efficiently
and higher
conveying
and displaying
neces-
to all participants.
is very important.
skills. Dick Kohrs
specialist
As has been
stated
tion."
Engineering
is accomplished
further
by
functions
design
requires
the process
achieve
technical
Skunk
person
understands
as the people
works
and design
The T-model
a system
focus.
"The
to achieve
groups
have
integrity
is key
skills,
In
the goal
reward
system
of integration."
emphasizes
this
of the organization
good technical
is in the system;
i.e., the integra-
tasks
to ensure
by
that
integration.
worked
also been
successful.
Management
for technical
subsystems
each
There
and systems)
products.
in the same
to ensure
(technical
to successful
earlier
"You manage
of technical
them
is 90 percent
the design
order
putting
presented
of the product
his or her role and responsibility
selection
The
skills is the truism,
disciplines.
centers
people
products.
by compartmentalizing
Working
and accepts
3: Concept
times,
and
to be managed
integration.
Shuttle.
to also have
many
It emphasizes
has said that "Communications
it is key to quality
2: Just as important
Lesson
through
Discussion
1: The first lesson
Lesson
process
an information
information
category
integration."
design
well
is
and
then
compatible
are many
ways
to
on Saturn
and Space
must ensure
that each
integration.
It is generally
accepted
that
at least
80 percent
of the life-cycle
cost is determined
during
the concept
selection
stage. Pugh has said,
"Engineering
can never right a poor concept
selection."
The quality lever indicates
the same focus. The
process is iterative, and it weeds out poor concepts,
then looks in more depth at the remaining
concepts.
The process repeats with further increased
depth until a clear winner is established.
More than two new
technologies
are generally
too risky for the development
phase. The results of the trade studies and
sensitivity
analysis should be carried forward
for future reference,
along with the selected concept.
The
concept
206
selection
is therefore
critical
and must be emphasized
by the leadership.
Lesson4: Requirements,constraints,andcriteriadictatethe productdesign.Pughsays."It is the
mantle
of the design."
design
suffers;
Many
times
creativity
Criteria
perform
reducing
structure
should
Lesson
led to many
carefully
the "what's"
failure
totally
call. The balancing
the balancing
act, if not resolved,
many
and requirements,
programs
programmatic
is a mistake.
an all-welded
requiring
gleaning
Con-
structure.
many
redesigns.
out all the "how's"
requirements.
"When
and
downstream
of system
sensitivities
must find a way of designing
of what
into a system
and
of what
engineering."
This process
is therefore
The
in the
is usually
decision
functions
the design,
and technical
and operations.
and are solved
at high cost and reduced
You get some
you put energy
will take place. You get some
data.
the design
requirements,
are pushed
times
conflicting
Pye has said,
how that transformation
and
the program
6: Consideration
in the welds,
this point.
they say how it is to
which
led to essentially
constraints,
act is first of all among
then between
analysis,
problems
want. This you do by design
technical
redistribution),
constraints,
constraint
act between
determine
firm
mode
18 emphasized
the
that are essential.
what you don't
act requiring
Lesson
weight
Leadership
and fracture
you do not want.
it, you cannot
All major
to replace
is a balancing
you want and minimize
and flight
are used
some
transform
judgment
in Servant
what is to be accomplished,
tailor criteria,
of what
are, if they are too restrictive,
of saying
5: All design
with
and criteria
are lost. Greenleaf
fatigue
to only those
you want
a balancing
sometimes
standards,
instead
the design;
in the same way. The SSME
The all-welded
Each project
as constraints,
and innovation
they can dictate
be accomplished.
straints
As important
end
disciplines
a
(energy
Problems
occurring
in
through
operational
procedures
is crucial
to the design
performance.
and uncertainties
for off-nominal
conditions
process.
at a given probabilistic
level
of risk without over penalizing
the performance
and cost. Sensitivities
of the system to the parameter
variations
are a measure of the level of concern one should put on an issue or an interaction.
In general the
higher
the performance
environments,
example,
robustness
the higher
tolerances,
in the case of fatigue of metals,
is a desired method for dealing
the responses
category,
to perturbations
a robust
second,
requirements,
manufacturing
a robust
is designed
such
designing
within
design
design
predetermined
be one whose
response
are maintained
margins,
Robust
the response
of the response
design
to any variation
curve
is highly
In the first
is inherently
insensitive
to perturbations.
to perturbations;
however,
the variations
adding redundancy,
either individually
For
of the SN curve. Design for
A robust design is one where
falls into two categories.
acceptable
of the
nonlinear.
is sensitive
within
controlling
actively or passively controlling the response,
and constraints. Therefore,
several approaches,
used to accomplish
sensitivity
sensitivity/performance
managed.
be one where
that the responses
the
the sensitivity
curve is the inverse
with uncertainties
and sensitivities.
are adequately
could
could
etc. The
limits.
This
in significant
In the
the system
can be achieved
response
and/or developing operational
or together, are listed below
by
parameters,
procedures
that can be
robustness.
• Increase
margins
• Reduce
• Reduce
parameters
sensitivities
uncertainties
(response
to uncertainties)
° Redundancy
° Operational
design
procedures
All good
design
parameters
using
practices
appropriate
and constraints.
intelligently
account
philosophies,
for and deal with uncertainties
procedures,
and sensitivities
as
and tools.
207
Lesson7: In the final analysis
the design
and the product.
that the organization
learning,
using
must
the engineer's
acceptance,
inquiry,
Lesson
needed.
revolutionize
be a learning
judgment,
Finally,
the process,
are essential
wherever
as discussed
section 7.3.1, item 8. Ideas for improvement
design
optimization,
and efficient
process
208
designs
and continually
or may come
seek to improve
that constantly
metrics,
is complex
and laborious.
Apply
lessons
in section
5. High
leverage
can come from related
initiative,
unrelated
skills. This means
personal
mastery
and team
In the end it
the product.
Openness,
and the quality of the product.
Significant
improvements
are
learned,
and
innovative
to
areas
to explore
fields of research
seek
include
of the engineers
ways
those
listed in
such as multidisciplinary
fields. The keys to attaining
and judgment
that develop
and the organization.
that determines
possible.
it.
hones
development
process
and creativity
mind and the human
to the engineer's
from apparently
lie in the creativity,
innovation,
of the individuals
not deterministic
the design
the process
organization
the uniqueness/diversity
and advocacy
8:
Improve
judgment,
All else are tools and aids to the human
to the fullest
is usually
it is the engineer's
highly
who execute
effective
the design
8. CONCLUDING
This report
provides
a baseline
currently
practiced.
The various
acterized
by using
hardware/software
along
with their corresponding
ization
provides
is recommended
characterization
areas of emphasis
gates
effort.
In specific
survey
of experienced
practitioners
in aerospace
detailed
bibliography.
Categorized
lessons
enhancements
of the design
The launch
vehicle
design
function
The process
for improvements
have
was
as it is
was char-
system
that
been made.
A
included,
as were
recommendations
delineating
the following
planes
character-
and communication
of engineering
provided,
systems
process
design
task completeness.
information
suggestions
were
design
interconnected
on the essence
learned
process
Compartmentalization/reintegration
•
disciplines
Technical
integration
and discipline
areas
for launch
as was
a
for future
process.
•
•
•
and
integrated
process
below. The current
for determining
for a comprehensive
for any major
for the design
are shown
compartmentalization
decision
a framework
SUMMARY
has been characterized,
associated
illustrating
with
both the formal
subsystems,
and informal
design
aspects
elements:
functions,
associated
and
with design
functions
Design function (plane) features and related significant
Information
flow model associated
with subsystems
decision gates
and design functions;
i.e., the IxI and
N×N matrices
•
Major
activities,
interactions,
In addition
to the
characterization,
provided.
They
necessary
ancillary
features
of the
design
process
were
include:
•
•
Thumbnail
Essentials
•
Project
•
T-model
•
Requirements,
•
Design
•
Illustration
Finally,
to understand
and tasks.
sketch of process
considerations
technical
framework
of technical
sequence
including
of the design
the process
where
integration
architecture,
philosophy,
etc., definition
conceptual,
preliminary,
process,
characterization
they fit in the process,
ing the process,
and
(3) the necessary
characterization
applies
to the design
shown
provided
through
and detail
historical
the following:
and their interactions,
symbolism
of any launch
to develop
vehicle
design
stages
examples.
(1)A
means
for practicing
(2) a basis for understanding
a variety
regardless
of electronic
design
of the organization/project
engineers
and improvtools.
The
structure.
209
9. RECOMMENDATIONS
It is recommended
utilized
as a basis
improved
reliability,
These
the launch
for understanding
to increase
improvement
that
effectiveness
technologies
should
and operability
technologies
leads
include
that hardware/software
Likewise,
design
process
recommendations
• Utilize
the design
Refine
the present
- Work
requirements
process
the process.
and efficiency.
Lessons
be incorporated
to the need
The
be developed,
must also be advanced
current
should
developed
process
be
be constantly
be implemented
and process
The
advances
in launch
technologies
herein
must
are developed.
of hardware/software
for design
characterization
learned
as they
for revolutionary
technologies
technologies
Specific
design
and improving
the categories
is essential
vehicle
need
to improve
system
and process
cost,
technologies.
technologies.
It
and these activities
are currently
underway.
to achieve
and efficient
designs.
effective
process
technologies
are as follows:
process
characterization
as a basis
for understanding
process
to improve
and
improving
process
such as
the
process.
- Design
for simplicity
- Improve
design-to
models
-
discipline
analyses.
Integrate
Pursue
revolutionary
- Advanced
- Unified
integration
-
210
technologies
approaches
effectiveness
to avoid
stifling
for major
for high-fidelity
to the subsystems,
Improved
process
ideation
methods
for concept
toward
concept
design
advanced
analyses
technology;
life-cycle
attributes
such as cost and reliability.
of providing
who practice
and innovation
in the design
definition,
sizing,
and assessment
process
into
functions
and discipline
idea stimulus
a seamless
approaches;
whole;
i.e.,
seamless
e.g., direct
synthesis
functions
identification
Advanced
Those
and efficiency
creativity
improvements
compartmentalization/reintegration
related
The challenge
processes.
and criteria
unlimited
design
i.e., high-fidelity
access
to space
must continuously
design-to
requires
improve
methods
for performance
the best of people,
the process.
technology,
and for
and
APPENDIX
Figure
represent
eates
96 is the NxN
typical
on the vertical
information
information
inputs and outputs
the diagonal,
column.
DIAGRAM
flow
diagram
flow in the design
process
relative
its information
A--NxN
to various
outputs
Therefore,
engineering
FROM
from
REFERENCE
reference
for example
design
are shown
on the horizontal
connectivity
is represented
2
2. It was developed
launch
and discipline
vehicles.
functions.
row, and its information
among
all included
by MSFC
This figure
to
delin-
For each entity
on
inputs are shown
entities.
211
dl
_-
._g,,_ ":'_-':-_-'-':;_..",_-i_-]_--'-=
"_"'-" _"=
"_]:;Z_'7_._
i_-='_
'-"
_---'-- i_.-:'_
_ (-_,--." _'_"
--_"
I',_',_:- _'_
:_"----
....
w
""-'::'_
-
"....
............
:='-
i]iiil]
• _
7"---" _-- ......
'_'_
i
i
i
i,
]]]]i
[
!
_:...._-_.-_-_ -___ ==_ _-_- _-_
.......................
_:-.
i
Figure
212
96. NxN
matrix
from
KEY:
reference
, ELV, RLV,
2.
and RBCC
:=--
- RLV and RBCC
-,
RBCC only
I
APPENDIX
Appendix
Space
Shuttle
B is an extract
engineers
the parameter,
BmSPACE
of certain
developed
the parameter
SHUTTLE
portions
matrices
values
PARAMETER
of the Space
MATRIX
Shuttle's
parameter
for each event and each basic design
or reference
source,
the 3-sigma
ITEMS
matrix
(figs. 97-99).
area. The matrix
parameter
uncertainties,
identifies
and, where
applicable,
area based
the procedure for usage. The parameter
matrix was developed by the specialists
in each discipline
on a combination
of historical
data, current analysis, and current testing. The parameter
matrix
document
for a vehicle
values
design
must be a living
(reducing
if possible)
as the design
list of interacting
parameters,
both natural
definition
to assure
and the data
are central
using uncertainties
and uncertainty
uniformity
coupled
definition
document,
changing
Critical
to the process
matures.
and induced.
in the design.
New systems
The discipline
to its development.
In the final
with sensitivities
and appropriate
cannot
both the base (mean)
specialists
analysis,
is development
need a comparable
of a comprehensive
parameter
with their knowledge
design
weighting
and uncertainty
trades
metrics.
matrix
of the system
(balancing
act) are made
The importance
of parameter
be overemphasized.
213
MARSHALL
ORGANFZAI1ON
SYSTEMS
SPACE
FLIGHT
CENTER
NAME
DYNAMICS
R. RYAN
LABORATORY
CHART
AFSIG
NO.:
REVIEW
DATE
15
APRIL
Parameter
Matrix
Event
Discipline
Trajectory Performance
Pogo
Flutter
Control
Thermal
Liftoff Clearance (Drift)
Separation
Loads
Environments
Overpressure
Acoustic
Shock
Winds
Propulsion
Dynamics
Criteria
Failure Modes
Prelaunch
Launch
Max Q
Max G
Pre-SRB Separation
SRB Separation
Post-SRB Separation
Second Stage Ascent
ET Pre-Separation
ET Separation
Total Ascent
Figure
214
1986
97. Parameter
matrix.
ORGANIZATION
MARSHALL
SYSTEMS
SPACE FLIGHT
NAME
CENTER
DYNAMICS
R. RYAN
LABORATORY
BASIC
CHART
PARAMETERS
DATE
NO,:
APRIL
16
1986
Analysis Tolerance
SRM Propulsion
• TC227A-75 Thrust Versus Time Curve Per SE--O19-083-2H
(SRB System Data Book) for Bulk Grain Temperatures
(TC227H Is Proposed as Update)
• Flight-to-Flight Propellant Burning Rate
{
ETR - 81 °F (Mean)/83.4 °F (Max)
W-I-R - 52 °F (Mean)/44.5 °F (Max)
{
+ 5.3% (One SRM)
+ 4.7% (Two SRM's)
• Thrust Level Development Uncertainty
+ 3%
• Thrust Oscillation (Dynamic Factor Assumed for
Loads Analysis)
+ 5%
• Steady-State Thrust Mismatch Between Motors
85,000 Ib (Ref. vol. X,
fig. 3.3.2.2e)
• Thrust Misalignment
+0.75 ° Per SRB
• Flight-to-Flight Thrust Level Dispersion
+
Both Motor
Motors
+ 4.9%
5% Single
Aerodynamics
• Pressure Distribution Test Data Match with Aerodynamic
Coefficient Test Data
+_3%
• Elevon Deflection Schedule #6 (Hinge Moment Limiting
Feedback) Per Rockwell Internal Letters ACDA/FSA/76-527
and 531
ASeo= f (__CHM = 0.02) Aero
Data Adjusted to New
(SeO+ ASeO)
• SD72-SH-0060-2
None
(Mated Vehicle Aero Design Data Book)
Values Per PRCB Briefing on
8/18/-76 MCR 3378 "5.3 Ascent Load
• Include Aerodynamic Tolerance Effects on Coefficients:Wind
Tunnel Deviations Plus Power-on Deviations Plus Reynolds
Number Effects
Figure
98. Basic
Adjustments"
parameters.
215
MARSHALL
ORGANIZATION
SYSTEMS
FLIGHT
NAME
CENTER
R. RYAN
BASIC
LABORATORY
CHART
SPACE
DYNAMICS
PARAMETERS
DATE
(Continued)
NO.:
APRIL
17
1986
Main Propulsion System
Analysis Tolerance
• 3 SSME Thrust Level Throttling Range
• Thrust Oscillation (Dynamic Factor Assumed
Only for Load Analysis)
• Equal Throttle Settings on All SSME's
• With One SSME Out, The Two Remaining SSME's
Operate at 109% Thrust
• Thrust Misalignment
• Mixture Ratio (6:1)
• Variations in ET Propellant Load Left at
Meco Result From Off-Normal SRM/SSME
Performance and SSME Throttling History
50% (MPL) to 100% (FPL)
± 5%
None
None
+ 3° Per SSME
None
None
Mass Properties
None
None
None
• Minimum Payload of 2,500 Ib (Mission 3B)
• Maximum Payload of 32,000 Ib (Mission 3A)
• Maximum Payload of 65,000 Ib (Mission 1)
Flight Control and Guidance
None
• Rockwell Control #7 Per SD73-SH-0097-1
(Integrated
Vehicle Flight Control System Data Book)
• Elevon Schedule #6 (Hinge Moment Limiting Feedback)
• Platform Misalignment
• Accelerometer Misalignment
• Accelerometer Null Offset (Time Variable)
_+0.02 Hinge Movement Coefficient
±0.5"
+0.5 °
0.010 to 0.025g (Pitch)
0.08 to 0.015g (Yaw)
0.0248
± 0.0083 °
1.5 MA
+2 =
• Accelerometer MDM Bias
• IMU Attitude Error
• Actuator Hysteresis
• Rate Gyro Misalignment
Figure
216
98. Basic
parameters
(continued).
MARSHALL
ORGANIZATION
SYSTEMS
DYNAMICS
LABORATORY
CHART
SPACE
FLIGHT
NAME
CENTER
R. RYAN
BASIC
PARAMETERS
DATE
NK_,:
(Continued)
18
APRIL
Flight Control and Guidance (Continued)
Analysis Tolerance
• Rate Gyro Hysteresis
• Rate Gyro MDM Bias
• Rate Gyro Zero Offset
• SRB and SSME Forward Loop Gain
_+0.02 deg/sec
+ 0.12 deg/sec
+ 0.15 deg/sec
+ 10%
1986
External Environment
• 95% Seasonal Winds Based on Monthly Wind
Ellipse Data for WTR and ETR (TMX-73319)
• Basic q_ql3: 95th Percentile Wind Envelope
Plus 3 m/sec Gust Plus 50th percentile Shear
Random qe-/ql3: FCS System Effects; 6 m/sec Gust
(i.e., 9 m/sec Minus 3 m/sec) and Shear up to 99th Percentile
None
Display qcdq!3 Envelopes: Basic Plus FCS Effects:
Basic Plus 6 m/sec Gust and Shear Up to 99th Percentile
Vehicle Dynamics
None
None
None
• First 50 Bending Modes with 1% Damping
• Aeroelastic Effects
• Flutter Stability
- First 20 modes
- Control System Feedback Represented
- Parametric Variation of Actuator Stiffness
Failure Modes
• Numbers 1,2, or 3 SSME Out Anytime After Lift-off
• TVC Failure By-Pass Transient
Figure
98. Basic
parameters
(continued).
217
MARSHALL
ORGAN_A_ON
SYSTEMS
NAME
FLIGHT CENTER
R.
"LABORATORY
CHART
SPACE
DYNAMICS
BASIC
DATE
NO.:
(Continued)
19
APRIL
Analysis Tolerance
Analytical Approach
• Trajectory Logic Superimposes Engine-Out
Squatcheloid on No-Failure Squatcheloid
• Conduct Loads Survey Around Squatcheloid Using
Rigid-Body Squawkr Program to Calculate Max/Min
Wing and Elevon Loads and ORB/ET and SRB/ET
Fitting Loads
• Flexible-Body Dynamic Response Calculated for Final Loads
Combination
Method
• qcdql3 FCS Tolerance added (+_700 psf-deg q(x; + 700 psf-deg q13)
• 85% Gust Timed 6 sec After SSME Failure in 85% Max Shear
or Full Gust 6 sec After SSME Failure Followed by Full
Design Shear After SSME Failure. Sequence of Events
Selected For Maximizing Loads
• SRB Thrust Dispersions:
• SD73-SH-0069-1,
-2, -3, and -4 (Structural Design Loads
Data Book)
• SD73-SH-0097-1
(Integrated Vehicle Flight Control System
Data Book)
Figure
218
RYAN
PARAMETERS
98. Basic
parameters
(continued).
1986
MARSHALL
ORGANIZATION
SYSTEMS
FLIGHT
NAME
CENTER
R.
LABORATORY
CHART
SPACE
DYNAMICS
BASIC
DATE
Lift Off
NO.:
APRIL
2O
1986
Analysis Tolerance
SRM Propulsion
• TC227A-75
RYAN
PARAMETERS
Thrust Versus Time Curve Per SE-019-083-2H
(SRB Systems Data Book) For Max/Min Grain
Temperatures (TC227H 1Proposed as Update)
90 °F (WTR)
(ETR)
40
• Thrust Level Development Uncertainty
_+3%
• Steady-State Thrust Mismatch Between SRM's
35,000 Ib
• Flight-to-Flight Thrust Level Uncertainty
+ 4.9%
5% Single
Both Motor
Motors
• Thrust Buildup Rate Development Uncertainty
Ref: SDIL SRM76-037
• Thrust Misalignment
+ 0.50% (Both); 0.707 ° (One)
Aerodynamics
None
• Ground Wind Drag Coefficients Per SD72-SH-0060-2
(Mated Vehicle Aero Design Data Book) and
Rockwell Internal Letter SAS/AERO/75-430
Main Propulsion
None
• 3 SSME's at 100% Thrust (RPL) to 109% Thrust (RPL)
Figure
99. Liftoff
load parameters.
219
ORGANrZAllON
MARSHALL
SYSTEMS
FLIGHT
NAME
CENTER
R. RYAN
LABORATORY
CHART
SPACE
DYNAMICS
BASIC
NO,:
PARAMETERS
DATE
Lift Off
21
APRIL
Mass Properties
Analysis Tolerance
• Minimum Payload of 2,500 Ib (Mission 3B)
None
• Maximum Payload of 32,000 Ib (Mission 3A)
None
• Maximum Payload of 65,000 Ib (Mission 3A)
None
Miscellaneous
None
• SRB/MLP Holddown Bolt Preload (750,000 Ib)
Flight Control and Guidance
None
• Rockwell Control No 7 Per SD73-SH-0047-1
(Integrated Vehicle Flight Control System
Data Book)
• All Nozzles Gimbal But SRB Nozzle Gimbal
Limited to 2° for First 5 sec
+0.17
+ 0.23 ° (SRB)
(SSME)
• SRB Mistrim to 0° Until SSV Clears the Launch
Pedestal
None
• STB TVC Misalignment
2 (_ RSS Each SRB in
Worst Direction
External Environment
• 95% Wind Speed (One Hour Exposure)
None
• Peak Wind Speed
24 Knots (Max)
• Tuned Gust (Worst Case)
None
Figure
220
99. Liftoff
load parameters
(continued).
1986
MARSHALL
ORGAN_A_ON
SYSTEMS
FLIGHT
LAME
CENTER
R. RYAN
LABORATORY
CHART
SPACE
DYNAMICS
BASIC
NO.:
PARAMETERS
DATE
Lift Off
22
APRIL
Vehicle Dynamics
Analysis Tolerance
• First 50 Bending Modes with 1% Damping
None
1986
Failure Models
• None
Analytical Approach
• Digital Simulation of Vehicle Flexible Body
Response Due to Applied Forces and Release of
Base Constraints
Combination
Method
• Sequence of Events Selected or Max Loads (WOW)
• RSS Similar Uncertainties as a Group Then Add Groups
(+ 2 G Deviations) in Worst-On-Worst Combination
Documentation
of Results
• SD73-SH-0069-1,
Data Book
-2,-3
and -4 Structural Design Loads
Figure
99. Liftoff
load parameters
(continued).
221
APPENDIX
Glossary
Format:
terms,
which
second
section,
The glossary
C--GLOSSARY
is divided
into two sections.
identifies
a group
number
where
grouped
together
with related
C.1
The first section
the definition
terms
is located.
to help clarify
Alphabetical
The
is an alphabetical
definitions
index
of all
are given
in the
in Group
No.
the definitions.
Index
Term
Located
Attributes
...............................................................................................................................................
2
Balancing
Act ........................................................................................................................................
4
Critical design
review
(CDR)
Compartmentalization
Component
Concept
Conduits
...........................................................................................................................
............................................................................................................................................
selection
Conceptual
................................................................................................................
1
3
3
...................................................................................................................................
1
.................................................................................................................................
1
design
.................................................................................................................................................
6
.............................................................................................................................................
2
Constraints
Design
certification
Derived
requirements
Design
cycle
Design
function
.....................................................................................................................................
3
Design
phases
........................................................................................................................................
1
Design
stages
.........................................................................................................................................
1
Detail
design
..........................................................................................................................................
1
Element
..................................................................................................................................................
3
Formal
integration
4
Flight
readiness
222
review
(DCR)
........................................................................................................
............................................................................................................................
..........................................................................................................................................
.................................................................................................................................
review
(FRR)
...............................................................................................................
1
2
1
1
Gates..................................................................................................................................................
2,6
Informal integration...............................................................................................................................
4
IxI matrix ...............................................................................................................................................
6
Life cycle attributes...............................................................................................................................
2
Manufacturingstage..............................................................................................................................
1
Margin ...................................................................................................................................................
5
Missionconceptreview(MCR) ............................................................................................................
1
Metrics...................................................................................................................................................
2
Minidesigncycle ...................................................................................................................................
1
Mission
NxN
statement
matrix
...................................................................................................................................
9
............................................................................................................................................
6
Operations
..............................................................................................................................................
1
Parameters
(design)
5
...............................................................................................................................
Part .........................................................................................................................................................
3
Parts
....................................................................................................................................
3
...........................................................................................................................................
2
of a system
Performance
Phases
(of design)
..................................................................................................................................
Planes
.....................................................................................................................................................
1
6
Preliminary
design
.................................................................................................................................
i
Preliminary
design
review
1
(PDR) ..........................................................................................................
Reintegration
.........................................................................................................................................
3
Requirement
allocation
3
Requirements
.........................................................................................................................................
2
.....................................................................................................................................
4
Risk assessment
Sensitivity
..........................................................................................................................
..............................................................................................................................................
System
requirements
Stages
(of design)
review
(SRR)
......................................................................................................
..................................................................................................................................
5
1
1
223
Subprocesses
..........................................................................................................................................
1
Sub-subsystem
.......................................................................................................................................
3
Subsystem..............................................................................................................................................
3
System...................................................................................................................................................
3
Systemsintegrationandverification .....................................................................................................
1
Tasks......................................................................................................................................................
6
Technicalintegration.............................................................................................................................
4
T-model..................................................................................................................................................
4
TechnologyReadinessLevel (TRL) ......................................................................................................
2
Uncertainty............................................................................................................................................
5
Verification............................................................................................................................................
1
Workbreakdownstructure(WBS) ........................................................................................................
6
224
C.2
GROUP
1
Design
stages.
manufacturing,
The
design
stages
consist
and systems
integration
Historically,
there
Definitions
of conceptual
and verification.
design,
preliminary
These design
design,
stages are followed
detailed
design,
by the operational
stage.
Design
stages
phases.
defined
• Phase A--Preliminary
• Phase B--Definition
been
five design
C--Design
• Phase
D---Development
• Phase
E--Operations.
Subprocesses.
There
are four "provide
• Formulation--Define
program
• Approval--Determine
program
• Implementation--Deliver
• Evaluation--Assess
aerospace
that have
been
replaced
by the design
for detailed
study.
It occurs
Multicriteria
decision-aiding
safety, operability,
Preliminary
early
in the
techniques
concepts.
where
process
and programmatic
when
many feasible
alternative
only top-level
decision
conceptual
are determined
parameters
(could
are known.
be a single alternative)
cost, schedule,
from trade and sensitivity
process
alternative
is the best and then to establish
concepts
follows
commitments.
concepts
system
is based on performance,
and TRL figures of merit obtained
This part of the design
of the selected
subprocesses.
are used to reveal the best alternatives
The down-select
design uncertainty,
design.
and capabilities"
readiness
That part of the design process
from the many proposed
products
program products and/or capabilities
the ability of program
to meet its technical
design.
which
phases
analysis
• Phase
Conceptual
have
above.
design,
and its purpose
a baseline
design
reliability,
studies.
is to determine
concept.
In this
stage, the configurations
are further matured,
and the significant subsystems
are designed
for inclusion
in
the assessment.
In addition, refined analyses, simulations,
and tests data are developed for trade and sensitivity
assessments.
All system
and updated
multicriteria
support, manufacturing,
performance,
cost, schedule,
test, and operations
decision-aiding
techniques
reliability,
safety, operability,
requirements
are also defined.
are used to reveal the best configuration
from trade
and sensitivity
studies relating to the launch vehicle, all supporting activities,
This downselected
configuration
then becomes the baseline for detail design.
and all supporting
systems.
Detail
an engineering
(drawings,
During
this part
specifications,
plans,
final development,
manufacturing,
of the design
process,
the goal is to provide
etc.) of a tested and producible
verification,
uncertainty
on
data obtained
design.
and design
Refined
based
design.
Additionally,
plans
description
are updated
for
and operations.
225
Manufacturing.
developed,
During
this
part
manufactured/coded,
Systems
integration
of the process,
and verification.
and software)
associated
functionality,
and verification
facility,
and
This is the final stage of vehicle
with the vehicle
flight ready. All results
flight,
GSE
hardware
and
software
are
and documented.
and operations
that the design
are documented
are assembled,
requirements
including
development.
tested,
and constraints
anomalies
and lessons
All systems
(hardware
and checked
for compatibility,
are satisfied
and the system
is
learned.
Operations.
Operations
consists of two parts. The first part pertains to vehicle development.
It is here that
it is determined
if the launch vehicle satisfies the mission need statement
or not. If it does not, then flight
constraints
are required.
The second
Then routine
operations
are established
and lessons
learned.
Concept
selection.
Many
are conceived,
evaluated,
decision-aiding
techniques
concepts
or accepted
is based
design
uncertainty,
process
levels
during
the selected
Design
or around
concept
maturity
PDR;
in a number
functions
of design
develop
at increasing
cycles
such
is applied
until one concept
some
(iterations).
knowledge
is finally
and reduce
risk (design
cost,
selected.
concepts.
reliability,
is acquired
through
after conceptual
design,
uncertainty)
a particular
through
analyses,
and verification
stages. Through
the process
of formal
design
determined
by the design
functions
via the discipline
assessed
at the system
is conformance
of the attributes
their balance,
consistent
then
interactive
another
cycle
is initiated
attributes
from the previous
Minidesign
cycle.
operations,
etc.,
and does
not impact
redesign
request
If a problem
procedures,
consistency,
and
the appropriate
and the design
in the requirements,
upon results
philosophy,
and/or
with the required
could be changes
of the assessment
compatibility,
with the aforementioned
balanced
226
focus
process
from the conceptual
and informal
criteria,
associated
data
level of maturity
repeated
until
ground
trends.
and testing
design
through
technical
integration
functions
are
to the overall
rules,
If the
the
etc.,
as well
as
attributes
are not
and risk has not been
achieved,
a set of appropriately
level of risk is achieved.
At the initiation
constraints,
procedures,
philosophy,
is completed
simulations,
integration
constraints,
Then
stage, the discipline
for each
level. The
proceeds
design
systems
requirements,
usually
design.
etc.) of the design process
as the design
system-levied
As the
technique
selection
of penetration
the attributes
safety,
analyses,
decision-aiding
levels
cycle,
The
studies.
The final concept
immediately
cycle during
process
proposed
schedule,
concepts
Multicriteria
and operations.
preliminary
For each design
Initially,
from trade and sensitivity
with the multicriteria
development,
design,
process.
of anomalies
requirements.
from the many
to the discriminators
have occurred
to final design,
system
as performance,
related
are determined.
and documentation
in the design
top-level
of merit obtained
knowledge
cycle. Each stage (e.g., conceptual
early
upon
knowledge
however,
proceeds
of results
the best alternatives
discriminators
additional
of system
based
and TRL figures
and tests. This additional
at various
occurs
proceeds,
upon
after all the flight constraints
evaluation
are developed
are used to reveal
decision
occurs
include
alternative
operability,
simulations,
which
and rejected
downselect
design
part of operations
of each design
criteria,
ground
matured
and
cycle
there
rules, etc., based
cycle.
is indicated
then after assessment,
by analyses,
a redesign
the entire
system,
then
also without
perturbing
the entire
guaranteeing
that all the appropriate
may be required.
the appropriate
system.
simulations,
Technical
requirements
testing,
manufacturing,
assembly,
If the redesign
is of a localized
and discipline
functions
design
integration
are satisfied
can be accomplished
and balanced.
nature
execute
the
via a change
Mission concept
with functional
System
review
(MCR).
and performance
requirements
and understood.
design
(SRR).
(PDR).
Demonstrates
that the preliminary
and technical
risk. The design
Critical
design
design
Verifies
The design
drawings
are the "build
to" baseline
Design
certification
review
and assesses
corrective
verification
process.
Flight
readiness
accomplished.
when
objectives
are about
design
complete.
requirements
etc.,
all the requirements
90 to 95 percent
complete.
The
of the production
and verification
cost, schedule,
results
Determines
what requirements
were met, reviews
This review
is usually
Certifies
that the system
vehicle,
selected.
review
are
conducted
from verification
of a successful
analyses,
significant
after the manufacturing,
is flight
ready
system,
and all associated
operational
a baseline
plans.
the design.
the launch
been
and establishes
results
(FRR).
are defined
of successful
the "as-designed"
actions.
has
with acceptable
The results
Evaluates
This includes
along
are evaluated.
approach
(DCR).
review
and concepts
to final design.
that the design meets
and approval
agreements,
requirements
10 percent
to proceed
and system
the basic
meets all the system
are about
(CDR).
to certify
mission
procedures,
Conducted
drawings
review
and simulations
Assesses
that the mission
techniques,
and the authority
review
for manufacturing.
Demonstrates
management
review
to" baseline
review.
requirements.
review
In addition,
Preliminary
the "design
First formal
tests,
problems,
assembly,
and all flight
objectives
and
can be
teams.
GROUP2
Mission
statement.
The fundamental
a launch vehicle to deliver
not to exceed $zzz.
The conditions
the system
must have. Requirements
value.
constraints,
In more
and derived
Constraints.
requirements"
certain
Another
Derived
top-level
usage,
requirements
that the designed
must meet.
Requirements
that is, they require
requirement
for
of at least yyy for a cost
specify
what
that the specified
are taken to mean the combined
system
in that they require
type of constraint
Requirements
statement
but which
requirements.
They
or to be imposed
system
are "equalities;"
orbit at a reliability
a basic
attributes
attribute
equal
set of requirements,
must be less than or must be greater
that the specified
attribute
is that the TRL of any technology
than. Constraints
be less than or greater
used
in the design
than a
be greater
TRL.
requirements.
the mission
to a specified
for example,
requirements.
are "inequality
value.
of payload
that the designed
general
The conditions
than a specified
of need for a system;
xxx pounds
Requirements.
a certain
statement
or constraints
are created
during
may be identified
that are not top-level
the design
by a design
process
function
requirements
as a result
or discipline
associated
of designing
to be imposed
with
to meet the
on itself,
on others.
227
Attributes. Propertiesof the designed
reliability,
etc. An attribute
Performance.
is a property
In this document,
or its subsystems,
where
on the vehicle.
Examples
vehicle
subsystem,
strictly
Life
mean
cycle
attributes.
Technology
Readiness
scale;
ranging
values
from the life cycle
Level
from
(TRL).
of the launch
vehicle
requirements
imposed
mass
specific
is a physical
safety,
than the conventional
performance
The maturity
As used in this document,
metrics
are quantifiable
measure
of attributes"
that quantify
parameters
(TPM's),
is, however,
fraction,
attribute
(or attributes)
reliability,
operability,
usage
of performance
to
a move
three
and (3) metrics.
TPM's
are used
to track
process,
not the product.)
Gates.
Events
in the design
process
of design
constraint.
To pass the gate, the design's
the design
must be changed
measures
of metrics
(see reference
of these
where
technology,
in the engineering
In reference
the progress
above.
Life
cycle
attributes
terms
of attributes
applied
community
by NASA's
19, figures
of merit
and manufacturing.
of the design
must meet
or the requirement/constraint
(see following
in the recent
to apply
19). In the past some
are (1) figures
an attribute
attribute
as measured
TIlL
mature).
is a definition
the system
Specifically,
as defined
of a given
to 9 (most
used interchangeably.
of merit,
note).
past and applied
specific
of these
definitions
terms
(2) technical
have
to
been
performance
are used to quantify
requirements.
Metrics
related
are measures
is compared
the requirement
to the
with a requirement
or
or constraint;
if it does not,
this follows
a hierarchy
must be relaxed.
3
of a system.
compartmentalization
A system
can be compartmentalized
into smaller
the subsystems
of the hierarchy
228
behavior
the physical
of cost,
cost,
etc.
mature)
certain
subsystems;
is broader
other than
operability,
There
Parts
attributes
properties,
or a constraint.
payload-to-orbit,
TPS mass density, etc. Performance
attributes
reliability,
in this document.
GROUP
the physical
include
1 (least
"Quantifiable
measures
with a requirement
has an effect on meeting
of performance
Vehicle
safety,
(Note:
may be performance
payload-to-orbit.
include cost,
Metrics.
These
means
of performance
is distinct
etc. Note also that this definition
typically
behavior
of measures
which
or subsystem.
that can be compared
performance
that physical
impulse of the propulsion
of the launch
system
are given
and smaller
are compartmentalized
specific
names,
parts.
into parts.
Generically,
Usually
the system
into sub-subsystems,
such as in the following
Level
Specific
Name
System
Launch
vehicle
Subsystem
Propulsion
Element
Liquid
Component
Part
Turbopump
Turbine blade
engine
is compartmentalized
etc. Sometimes
examples
which
the various
are not unique:
of
into
levels
Designfunction.The activity
of creating
(top plane)
The primary
products
of the other design
functions
aspects
of the design,
as fed to the system
plane.
Discipline
function.
process
4.3.1.
The activity
by specialists
Compartmentalization.
compartmentalization:
compartmentalized
of the design
Reintegration.
The process
system
reintegrated
are the specifications
(lower
various
or system.
and drawings
planes)
simulation,
technical
for its subsystem
in section
testing,
areas
The primary
are the descriptions
See also the discussion
such as analysis,
in the
subsystem
or system.
of their respective
4.3.1.
etc., that is performed
of expertise.
products
See
also the
during
the
discussion
in
Separation
of the design process into managable
parts. There are three types of
(1) Separation
of a system
into subsystems
(subsystems
can be further
into sub-subsystems);
(2) separation
of the design functions
for each subsystem;
and
(3) separation
complete
function
for a specific
of a system
design
section
design
a design
design.
functions
into the discipline
of recombining
Discipline
into subsystems,
activities
necessary
to achieve
the design.
the compartmentalized
parts
of the design
process
functions
are reintegrated
into design
and subsystems
are reintegrated
into the total system.
functions,
design
to form
functions
a
are
Requirement
allocation.
Identification
and assignment
of requirements
by the system design function
the subsystems
and lower design functions.
Requirements
are divided
and allocated
with the intent
producing
a total design that will achieve the best balance among the subsystems
and requirements.
to
of
GROUP4
Technical
Integration.
compartmentalized
enabled
The interactive
parts
by formal
reintegrate
and informal
information
their part affects
the total system,
design
addressed
are being
T-model.
portion
leader
via the systems
integration
vertical
of technical
of the subdivision
plane.
is accomplished
as consisting
represents
portion
by design
and
focus
with a systems
Integration.
A communication
activity
function
and all other
design
ensures
process,
Technical
whereby
the
integration
is
of all participants
that interactive
on how
aspects
of the
It ensures
the requirements,
by the leader
of three
of the crossbar
functions.
of discipline
Formal
parts.
horizontal
of a horizontal
integration
represents
The
The
subdivision.
is accomplished
informal
third portion
engineers,
crossbar
integration.
Informal
of the T-model
and it signifies
The
by the
is the
their
indepth
between
the system
design
and uncertainties
(developed
by the
An associated
activity
perspective.
functions.
of formal integration
is resolving
inconsistencies,
unnecessarily
integration.
discipline
Formal
accomplished
by a system
that consists
the activities
capability
satisfy
design.
of two parts as a result
formal
The lower
leg of the T. This represents
functions)
in the design
total
that continually
integration
discipline
design
successful
flow methods,
and by leadership
of a "T" can be visualized
upper
among all participants
and balanced.
A representation
portion
activity
into a balanced,
that consists
of interactions
that the attributes
constraints,
etc., and they are compatible.
engineering
conflict between
design
high interactions
and sensitivities,
via the system
functions
when incompatibilities,
etc., occur. These
activities
are
plane.
229
Informal Integration.
in a design
data
and
design
A communication
function
and interactions
information
function
Balancing
exchanges
the
and accurate
Act. There
are two types
of balancing
interactive
discipline
functions,
and disciplines
Risk Assessment.
of probabilities
by the launch
and design
An evaluation
attributes
The
focus
and their
acts. The first relates
discipline
activities
functions
consists
associated
to the system
and the operational
trade
balances
where
attributes
that addresses
consequences
among
of these
uncertainties
design
the required
process
versus
of interactions
functions.
of
with the
manner.
vehicle
activities
to achieve
of success
design.
are made
among
with acceptable
technical,
where
the program
The second
relates
the subsystems,
to
design
uncertainties.
cost, and schedule
risk. It uses an estimate
of failure.
5
Parameters
(design).
Design
and (2) one that the designer
design;
e.g., independent
where
the designer
Uncertainty.
quantity
cannot
has control
term
that fall into two categories:
control.
The controllable
of the design
(1) One that the designer
parameters
process.
The latter
are measures
can control
that characterize
parameters
are environmental
the observed
or calculated
the
inputs
only over how they are characterized.
for the estimated
amount
by which
value
of a
from the true or mean value.
A measure
that can be defined
measures
variables
A general
may depart
Sensitivity.
when
to determine
in an efficient
are balanced
that consists
design
planes
requirements
GROUP
activity
between
of a system
as the amount
one of the independent
relationships,
variables
variables
depends
upon the application.
Margin.
The difference
predicted
maximum
between
value
of functional
that the dependent
differs
from
its reference
the value that a variable
of that variable,
of headroom
available
in meeting
unmodeled
uncertainties.
a hardware
differ
including
value
(baseline).
must not exceed
known
the requirement,
system,
and
parameter
may
or a software
from their reference
(baseline)
specific
calculus
The
(its requirement
variations.
be included
to allow
system
values
Margin
limit)
and the
is the measure
for contingencies
or
GROUP6
Planes.
plane
In the design
contains
Conduits.
Gates.
the various
Pathways
Events
process
model
delineated
activities
that are executed
within
information
between
planes
that represent
in the design
process
where
constraint.
To pass the gate, the design's
the design
must be changed
Tasks.
230
Specific
in this document,
activities
an attribute
attribute
must
by design
the design
flow among
of the design
functions
a design
function.
The
function.
the design
is compared
meet the requirement
or the requirement/constraint
accomplished
a plane represents
with a requirement
or constraint;
must be relaxed.
or discipline
functions.
functions.
or
if it does not,
IxI matrix. A matrix thatdefinesinformationflow amongsubsystems
andbetweena subsystemand its
nexthigherlevel system.Interfaceinputs,outputs,andconnectivityareshown.
NxN matrix. A matrix that def'mesinformation flow amongdesignfunctionsanddisciplines, showing
inputs,outputs,andconnectivity.
Work Breakdown Structure (WBS). An organizedlisting of theareasof work(tasks)requiredto produce
adesign.
231
REFERENCES
.
2.
Utterback,
J.: Mastering
Humphries,
W.R; Holland,W.;
Analysis
Pugh,
.
Process,"
the Dynamics
and Bishop,
MSFC,
Addison-Wesley
4.
"NASA
Systems
5.
Gordon,
J.E.: Structures,
6.
Pye, D.: The Nature
7.
Blanchard,
Engineering
Publishing
Handboook,"
07"Why Things
of Design,
B.; and Fabrycky,
Harvard
Reichold
Business
R.: "Information
NASA/TM--1999-209877,
S.: Total Design,
Cliffs,
of Innovation,
Flow
December
NASA
1995
Don't
Fall Down,
Decapo
Press,
Book
Corp.,
Engineering
and Analysis,
Design/
1986.
Prentice
Hall, Englewood
NJ, 1990.
2rid ed., MSFC-HDBK-1912A,
9.
"Project
Management
Handbook,"
MM
10.
"NASA
Program
and Project
Management
S.C.; and Clark,
K.B.:
7120.2A,
MSFC,
Processes
MSFC,
December
1994.
NASA
NPG
7120.5A,
Quantum
Leaps
1989.
and Requirements,"
3, 1998.
Wheelwright,
Speed,
Efficiency,
and Quality,"
Fleeter,
R.: Launchspace
"Revolutionizing
New York: Free
Product
Press,
Ryan,
R.S.: "Lessons
San Diego,
Development:
1992.
Learned
in Propulsion
System
the National
Design"
AIAA
Space Transportation
Joint Propulsion
System,
Conference,
CA, July 1995.
Gordon,
J.E.: The New Science
Petroski,
H.: To Engineer
of St_vng Materials,
Is Human:
Princeton
The Role of Failure
University
in Successful
Press, Princeton,
Design,
NJ, 1988.
St. Martin
Press,
New York, NY, 1982.
17.
232
Petroski,
H.: Design
University
Press,
in
Magazine.
Jenkins, D.R.: Space Shuttle
The Histo_ y of Developing
Walsworth
Publishing,
Marceline,
MO, 1997.
14.
Vehicle
1994.
New York, NY, 1969.
Handbook,"
11.
MA,
1999.
June
Engineering
April
in the Launch
SP-6105,
W.: Systems
Boston,
Co., New York, NY, 1991.
"System
,
School,
Paradigms:
1994.
Case Histories
of Error and Judgment
in Engineering,
Cambridge
Greenleaf,R.F.:Servant
Leadership,
Moody,
W.L.; Van Voorhees,
Evaluating
J.A.; Chapman,
Engineering
Designs,
Paulist
Prentice
Press,
New York, NY, 1977.
F.D., and Bahill,
Hall,
A.T.; Metrics
and Case
Studies for
1997.
233
BIBLIOGRAPHY
Abramson,
N.: "Dynamic
Admire,
J.R.; Tinker, M.L.;
Structural
Models,"
Admire,
J.R.;
Constrained
AIAA
and Ivey, E.W.: "Residual
Journal,
Flexibility
Vol. 32, No. 1, January
Function
Deployment,
Productivity
Function
Deployment,
Press,
Cambridge,
University
MA,
1988.
Academy
Press,
to Orbit,
National
Design
and Operations
M.: Introduction
to Design,
"Mass-Additive
Integrating
and Trubert,
M.: "A Shock
Spectra
Spacecraft
Structural
AIAA-75-811,
May
Bamford,
R.M.;
and Gayman,
W.H.;
Wada,
J.S.;
Interscience,
Bendat,
and
B.K.;
February
Piersol,
New York,
J.S.; and Piersol,
A.G.:
Engineering
1990.
into
Product
Design,
1992.
Technology
Conference,
NJ, 1962.
Method
to Determine
a Bound
for
1975.
"Equivalent
Spring-Mass
of Correlation
A.G.: Random
Data, Analysis
and Measurement
Analysis--A
Methodology,"
"Propulsion
System
Propulsion
Conference
and Exhibit,
Nashville,
Blair,
and
Ryan,
R.S.:
Role
March
1992.
234
and Impedance
of
System
for Normal
Modes,"
and
Spectral
Analysis,
Wiley
1980.
Biggs,
J.C.;
MA,
Aerospace
Applications
1986.
AIAA-92-1585,
Cambridge,
Cliffs,
for Verification
1971.
New York,
R.E.:
Method
SAE SP--636,
New York, NY, 1983.
R.M.;
of Constrained
1993.
DC,
AIAA,
Bamford,
Test
Washington,
Englewood
Laws,"
1996.
for Verification
Requirements
Hall,
"Augustine's
JPL TM No. 33-380,
Press,
Prentice
N.R.:
Loads,"
Model
Customer
Problems,"
Augustine,
SP-106,
1994.
Vol. 31, No. 11, November
Anon.: "Spacecraft
October 1985.
E.W.:
Test Method
AIAA Journal,
From Earth
and Ivey,
NASA
Models,"
Y.: Quality
Bendat,
Containers,"
M.L.;
Akao,
Asimow,
in Moving
Tinker,
Y.; et al.: Quality
Anon.:
of Liquid
Structural
Akao,
Cambridge
Behavior
Failure
"The
TN, pp. 1492-3796,
of Criteria
in Design
Procedures,
Wiley
AIAA/SAE/ASME/ASEE
July 6-8,
Interscience,
28th Joint
1992.
in Management
of Space
Systems,"
Bookout,RS.:"Statistically GeneratedWeightedCurveFit of ResidualFunctionsfor Model Analysisof
Structures,"NASA TM-108481,
NASA, Washington,
DC, February
1995.
Braun,
R.D.;
Powell,
Multidisciplinary
Lepsch,
Optimization
Rockets
32:3, May]June
Bruhn,
E.E:
Chamis,
R.W.;
Analysis
C.C.:
R.A.;
Strategies
Stanley,
D.O.;
and
for Launch-Vehicle
Kroo,
Design,"
I. M.:
AIAA
"Comparison
Journal
of Two
of Spacecraft
and
1995.
and Design
"Probabilistic
Probabilistic
Engineering
Christensen,
D.L.:
of Flight
Structural
Structure,
Analysis
Mechanics,
John Wiley
Methods
& Sons,
for Space
Vol. 2, No. 2, pp. 100-110,
"Advances
in the Application
H.A.: "Characteristics
of Space Shuttle
of Systems
New York,
Propulsion
1993.
System
Components"
1987.
Engineering
Procedures"
AIAA-96--4433,
1996.
Cikanek,
ASEE
23rd Joint
Collins,
Propulsion
J.: Failure
Sons,
New York,
Craig,
R.R.;
Conference,
of Materials
Main Engine
San Diego,
in Mechanical
Failures"AIAA-87-1939,
AAIMSAE/ASME/
CA, July 1987.
Desig_r--Predictions,
Prevention,
2d ed., John Wiley
&
1993.
and Bampton,
M.C.C.:
"Coupling
of Substructures
for Dynamic
Analysis,"
AIAA
Journal
61:7, July 1965.
Crandall,
S.H.;
and Mark,
W.D.:
Random
Vibration
in Mechanical
Systems,
Academic
Press,
New York,
Development,"
SAE
901863,
Aerospace
1963.
Cross,
Cyr,
N.: Engineering
K.J.:
"The
Role
Design
Wiley,
of Cost Analysis
Technical
Conference,
Deming,
E.: Out of the Crisis,
October
Den Hartog,
J.P.: Mechanical
Dieter,
Engineering
G.E.:
Methods,
New York,
in Manned
1989.
Spacecraft
1990.
Massachusetts
Vibrations,
Design--A
Institute
of Technology,
McGraw-Hill,
Materials
Cambridge,
MA,
1989.
New York, NY, 1956.
and Processing
Approach,
2d ed.,
McGraw-Hill,
New
York, NY, 1991.
Drucker,
Dym,
Ehrich,
EE:
Managing
C.L.: Engineering
F.F.; and Childs,
Engineering,
pp. 66-79,
for Results,
Harper
Design--A
Synthesis
D.: "Self Excited
May
& Row, New York, NY, 1984-86.
of Views,
Vibration
Cambridge
University
in High-Performance
Press,
1994.
Turbomachinery,"
Mechanical
1984.
235
Ertas,A.; andJones,J.C.:"The EngineeringDesignProcess."
Ferebee,R.C.: "Applicationof a ComputerizedVibroacousticData Bank for RandomVibrationCriteria
Development,"NASA TP 1998, NASA, March 1982.
Ferguson,
E.S.:
Engineering
and the Mind's
Eye,
Massachusetts
Institute
of Technology,
Boston,
MA,
Business
Consultants,
Ann
NASA-STD-5003,
October
1996.
1992.
Flugel,
C.; and Weisbrich,
Arbor,
MI, 1990.
Fox, J.: Quality
A.: "Voice
Through
Design,
of Customer
McGraw-Hill,
"Fracture
Control
Requirements
for Payloads
"Fracture
Control
Requirements
for Space
French,
M.: Im'ention
and Evolution,
Conversion
Japan
New York, NY, 1993.
Using
Station,"
Design
Steps,"
the Space
Shuttle,"
SSP 30558-B,
in Nature
June
1994.
and Engineering,
Cambridge
Press,
New York, NY,
1994.
Garrick,
I.E.;
"Aeroelasticity--Frontiers
Aircraft,
113:9,
September
Garrick,
I.E.; and Reed
April
hicles,
E.D.
(Editor):
AGARDograph
Goldberg,
B.E.;
MSFC,
lIl, W.H.:
"Historical
Development
"Vehicle
Response
to Atmospheric
Lecture,
AIAA
Journal
of
of Flutter,"
AIAA-81--O591-CP,
Atlanta,
GA,
Harris,
C.M.;
Hopkins,
Effects
on Launch
Ve-
Engineers,"
NASA
Engineering
"Toolbox"
for Design
Prentice-Hall,
Harvard
Business
Oriented
Inc., Engtewood
School,
and Crede,
C.E., Eds: Shock
H.: "Guidelines
for Dynamic
Environmental
to Reduced
Launch
October
Wind
1970.
of Dynamics,
of Paradox,
J.: "Approaches
Conference,
Disturbance,"
Report
1994.
D.T.: Principles
C.: The Age
Himelblau,
115, February
et al.: "Systems
Handy,
236
13th Von Karman
1976.
December
Greenwood,
Hubka,
Beyond,"
1981.
Geissler,
1358,
and
Boston,
and Vibration
MA,
Handbook.
Cliffs,
1995.
McGraw-Hill,
New York,
1976.
SAE
Aerospace
Technical
Criteria."
Operations
Costs,"
901877,
1990.
V.; and Eder, W.E.: Design
Science,
NJ, 1965.
Springer-Verlag,
London,
1996.
Humphries,
Solutions."
R.; Wegrich,
R.; Pierce,
NASA
MSFC,
October
Em,ironmental
Control
Systems,
Florence,
"Dynamic
Analysis
of Structural
Hurry,
W.C.:
Report
No. 32-530,
Ibrahim,
January
1964.
S.R.; and Mikulcik,
E.C.:
the Free Response,"
"Loads
Analysis
The Shock
of Spacecraft
Lovingood,
J.A.:
Response
Studies,"
"Management
McCarty,
E.; and Patterson,
1991; ESA and
of Major
J.; and
Italy, October,
Systems
"A Method
by Component
for the Direct
Bulletin
and Payloads,"
NASA-STD-5002.
for Including
TM X-53042,
System
Murphy,
1991.
and Vibration
"A Technique
NASA
W.: "A Survey of Spacecraft
Thermal
Design
AST, Fourth European
Symposium
on Space
Programs
J.M.:
Identification
of Vehicle
Synthesis,"
JPL
of Vibration
47, Part 4, September
the Effects
May
Mode
Technical
Parameters
from
1977.
Parameter
Variations
in Wind
1964.
and Projects,"
"An Assessment
NASA
NMI
of Liquid
7120.4,
November
1993.
Propulsion
in the
United
States,"
AIAA,
and Matrix
Interpretive
Systems
(SAMIS)
Prevention,
Failures
of Rolling
Element
July 1989.
Melosh,
R.J.; Deither,
Program
Report,"
Metals
Handbook,
Bearings,
Miller,
P.A.; and Brennan,
M.: "Structural
JPL TM No. 33-307,
American
I.; Freund,
December
9th ed.,
Volume
II, Failure
Society
for Metals,
J.E.; and Johnson,
Englewood,
Cliffs,
Mintzberg,
H.: Mintzberg
R.A.:
Airfi'ame
Noor, A.K.;
and Venneri,
S.L.: "New
and Loads,"
ASME,
New York,
1994.
K.: "Liquid
Propulsion
System
Pack, H., Jr.; and Young,
Pahl;
Washington,
and Beitz:
"Payload
Analysis
Park,
and
OH, pp. 490-514,
1979.
Probability
and Statistics
for Engineers,
Free Press,
New York,
1988.
Hong
Comlit
on Management,
Composite
NASA,
1966.
4th ed., Prentice
Hall,
NJ, 1990.
Niu, M.C.Y.:
O'Hara,
Metal
Analysis
L.E.:
Structures,
"Solar
DC, February
"Engineering
Test Requirements,"
and Projected
Kong
Aeronautical
Reliability---Design
Array
Press, Hong
and Space
for Reliability;"
Flight,
Dynamic
Augmentation
The Design
Council,
Springer-Verlag,
Kong,
Systems,
1992, Rev.
Design
Concepts
AIAA-89-2628,
Experiment,"
1996.
July
NASA
1989.
TP 2690,
1987.
Design,"
NASA-STD-7002,
July
London,
1984.
1996.
237
"Payload
Vibroacoustic
Peters,
T.; and Waterman,
Phadke,
M.S.:
Test Criteria,"
Quality
NASA-STD--7001,
R.: In Search
Engineering
W.; and Pikey,
B.; Eds: "Shock
Shock
and Vibration
Information
"Program]Project
Rao,
S.S.: The Finite
Ravindra,
M.K.;
Structural
Division,
Ricks,
Method
Galambos,
Coupled
craft Structures
and Mechanical
Structures,"
Nurre,
G.S.;
and Direct
Scofield,
Journal
of Guidance,
R.S.: "Practices
in Adequate
Ryan,
R.S.:
Analysis
"Systems
NASA
Space
Systems,"
NASA
Ryan,
R.S.:
"The
of Failure]Problems
R.;
February
Ryan,
Ryan,
R.; Bugg,
Role
NASA
and Verderaime,
Resistance
Factor
Design
of Improved
NY, 1982.
for Steel,"
Load Transformation
of Margins
Sims,
of Safety,"
January
1989.
J.L.:
"Dynamics
Jomwal
Matrices
of the
Proc.
and
for Launch-
Intl. Conf.:
"Space-
of Large
Space
Control
Vol. 7, No. 5, September-October
NASA
2893,
to Deriving
Design
Criteria
January
1984.
1989.
(Loads)
for Space
Shuttle
and Its
1981.
R.; Kiefling,
TM-78307,
1980.
September
in Engineering:
March
New York,
1978.
E; Ivey, W.; McComas,
TP-3213,
The
L.; and Jones,
A Commentary
J.: "Dynamic
on Failures
Testing
of
Experienced
-
1992.
V.: "Launch
Vehicle
V: "Systems
Design
Systems
Design
Analysis
Applied,"
AAIA-93-1140,
Analysis
Applied
to Launch
Vehicles,"
NASA
TP-3326,
1993.
R.; Schutzenhofer,
Phenomenon
Associated
and Vibration
Symposium,
238
Press,
SVMIO,
1975.
1993.
R.; and Verderaime,
February
Pergamon
Design,"
TP 1949 and 1950, December
Large
Ryan,
and
Structural
R.S.; Jewell,
Learned,"
14, 1996.
and Dynamics,
Approach
NJ, 1989.
and Summaries;'
of Defense,
November
Computation
H.N.;
Ryan,
Lessons
and
ESA SP-289,
Conovl
Reviews,
Cliffs,
1991.
of Engineering,
Testing,"
Ryan,
Payloads,"
Programs,
New York, NY, 1985.
Hall, Englewood
States Department
J.: "Derivation
Analysis,
Books,
Prentice
Vol. 104, No. ST 9, pp. 1337-1353,
ers-Spacecraft
R.S.;
Design,
7120.4A,
T.V.: "Load
E.; Klein, M.; and Reynolds,
Ryan,
NPD
2d ed., J. Wiley,
Element
and
NASA
United
1996.
Warner
and Vibration
Center,
Management,"
Rao, J.S.: Rotordynamics,
of Excellence,
Using Robust
Pikey,
June
L.; Jones,
L; and
with the Space
Colorado
Jewell,
Shuttle
Springs,
Main
R.: "Elimination
Engine
CO, October
Oxidizer
1979.
of Discrete
Frequency
Acoustical
Valve Duct
System,"
lOth Shock
Ryan,R.S.;et al.: "DynamicTestingof LargeSpaceSystems,"NASA
Ryan,
R.S.:
Meeting,
Ryan,
"Fracture
CPIA
Mechanics
Publication
514, NASA
R.S.; and Townsend,
The Approaches,
1993.
Ryan,
R.S.;
TP 3347,
The
D.D.:
DC, February
Mechanics
Ryan,
R.S • "Fracture
Langley
Research
Center,
May 2--4, 1989.
Ryan,
S.G.: "Limit
Cycle
Vibrations
Research
"The
Phenomena
Dynamic
JANNAF
NASA
Salomone,
T.A.:
Inc., 1995.
Should
Know
T.: "Vibration-Test
and Rockets
Schock,
May
R.:
"Solar
Force
Limits
32:2, March-April
Array
Flight
Methods
AIAA/ASME,
Nondestructive
Analysis
Spacecraft
1980.
Subcommittee
1989.
SDM
Design
Scharton,
Evaluation
Analysis/Design
in Turbomachinery,"
Engineer
May
September
in Space
Programs:
LaJolla,
CA, April,
of Tethered
Satellite,"
NASA
1993.
Overview,"
Every
Center,
AIAA-93-1381,
Safie, E; and Fox, E.P.: "A Probabilistic
June 1991.
"What
Nondestructive
of Probabilistic
and the Needs,"
K.; and Tomlin,
Washington
JANNAF
Langley
J.: "Application
Status,
Mowery,
NASA,
Overview,"
TM-78307,
Derived
TP 3181,
Approach
About
from
Evaluation
Subcommittee
December
for Launch
Meeting,
1991.
Systems,"
AIAA-91-3372,
Concurrent
Engineering,"
Marcel
Frequency-Shift
Method,"
AIAA
NASA
NASA,
Washington,
Dekker,
Journal
of
1995.
Dynamic
Experiment,"
TP 2598,
DC,
1986.
Schutzenhofer,
L.A.;
Des ign---Government
McConnaughey,
P.K.;
Prospective,"
AIAA-90-1825,
Senge,
P.: The Fifth Discipline,
Shen,
E; and Pope,
Technology,
1990.
Aerospace
Sobieski,
S.; and Goetz,
R.C.:
"Synthesis
Methods,"
Status
NASA,
Langley
Launch
System
Evaluation
Rev. B, Johnson
Space
Center,
NASA,
"Space
Design
Criteria
BP-8032,
Shuttle
Vehicle
August
Organi:ation,'"
of Composite
SAE 901836,
October
of Aircraft
Research
Advisory
December
(Structures),
H.V.:
"Role
of CFD
in Propulsion
1990.
and Development
Vehicles,"
"Space
McConnaughey
The Art of the Learning
D.: "Design
Report,
and
Structures
Center,
Doubleday,
Fairing
Using
New York, NY, 1990.
Structures
Integrated
for Space
Design
Launch
and Analysis
VA.
Team (LSEAT)
Integrated
Support
Plan,"NSTS
03211,
Shells"
NASA
5, 1991.
Buckling
of Thin-Walled
Doubly-Curved
1959.
239
"SpaceVehicleDesignCriteria (Structures),Buckling of Thin WalledTruncatedCones,"
September
"Space Vehicle
June 1971.
Criteria
(Structures),
Buckling
"Space Vehicle Design Criteria
BP-8083,
November
1971.
(Structures),
Discontinuity
"Space
Vehicle
(Structures),
Design-Development
"Space
Vehicle
BP-8040,
May
Design
Design
Criteria
BP--8019,
Design
Criteria
(Structures),
"Space
Vehicle
August
1985.
of Structural
Plates,"
in MetaIlic
Pressure
Stresses
Testing,"
NASA
BP-8068,
NASA
Vessels,"
SF--8084,
NASA
May
1970.
Fracture
Control
of Metallic
Pressure
Vessels,"
NASA
Preliminary
Criteria
for the Fracture
Control
of Space
Shuttle
Design
Criteria
(Structures),
Stress-Corrosion
Cracking
(Structures),
Structural
Criteria
"Space
Vehicle
Design
Criteria
NASA
BP--8087,
January
1971.
Steward,
D.V.: Systems
"Structural
Design
and Test Factors
of Safety
"Structural
Design
and Verification
Requirements--ISSA,"
Analysis
Sullivan,
R.: "A Coupled
Solution
Expanding
Polymeric
Composites,"
"System
Engineering
Taguchi,
G.: Introduction
Ullman,
D.: The Mechanical
Ulrich,
K.; and Eppinger,
yon Pragenau,
Strength
1980.
"Space Vehicle Design Criteria (Structures),
Structures,"
NASA SF-8095,
June 1971.
and Management,
Method
S.: Product
P.J.: The Technique
Walton,
M.: The Deming
Design
Applicable
to a Space
Shuttle"
Inc., New York,
NY, 1981.
NASA-STD-5001,
Materials,
MSFC,
McGraw-Hill,
NASA
1996.
1994.
Response
December
Institute,
of Decomposing,
TP-1987,
1994.
Inc., Dearborn,
New York,
McGraw-Hill,
March
& Sons Ltd., London,
Publishing
June
Vol. 27, No. 4, 1993.
Process,
Putman
June
the Thermostructural
Supplier
Sir Isaac Pitman
in Metals,"
SSP 30559-B,
and Development,
Books,
BP-8032,
American
for Turbomachiner),"
Periger
NASA
Hardware,"
of Composite
Design
of Design,
Method,
Books,
for Spacecraft
Engineering,
Engineering
Seals
Petrocelli
2d ed., MSFC-HDBK-1912A,
to Quality
G.: "Damper
Design
for Predicting
Journal
Handbook,"
Wallace,
240
NASA
1986.
MI,
1994.
New York,
1994.
1982.
England,
1952.
Co., New York, NY, 1986.
1986.
Wirsching,EJ.; et al.:"An Overviewof Reliability Methodsin MechanicalandStructuralSystems,"28th
Annual
Structures,
Wirshching,
Seminar
Structural
P.H., and Ortiz,
and Workshop,
Dynamics,
and Materials
Conference,
K.: "Reliability
Methods
in Mechanical
Univ. of Arizona,
Tucson,
Woodson,
T.T.: Introduction
to Engineering
Zarestsky,
E.: "Life
for Rolling
Factors
Design,
Bearings,"
AZ, January
1987.
and Structural
Design,"
13th Annual
1992.
McGraw-Hill,
STLE
April
Publications
New York,
1996.
SP-341,
1992.
241
REPORT
DOCUMENTATION
PAGE
Form
Approved
OMB No. 0704-0188
Public repoding burden for this collection of information is estimated to average I hOUrper response, including the time for revtewthg instructions, searching existing data sources
gathedng and maintaining the data needed, and completing and reviewing the collectk_n of information Send comments regarding this burden estimate or any other aspect of this
collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for InformationOperation and Reports, t 215 Jefferson
Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Projec_(0704-0188), Washington, DC 20503
1. AGENCY
USE ONLY
(Leave
B/ank)
2. REPORT
DATE
3. REPORT
May 2001
4. Trt'LE
TYPE AND
DATES
Technical
COVERED
Publication
5. FUNOING
At, K/SUBTrt'LE
Launch Vehicle Design Process: Characterization,
Integration, and Lessons Learned
NUMBERS
Technical
6. AUTHORS
J.C. Blair*, R.S. Ryan*, L.A. Schutzenhofer*,
and W.R. Humphries
7. PERFORMING
ORGANIZATION
NAMES(S)
ANDADDRESS(ES)
8. PERFORMING
REPORT
George
C. Marshall
Marshall
Space
Space
Flight
Flight
Center,
Center
AL
35812
M-1018
9. SPONSORING/MONITORING
AGENCY
NAME(S)
ANDADDRESS(ES)
10,
SPONSORING/MONITORING
AGENCY
National
Aeronautics
Washington,
DC
and Space
ORGANIZATION
NUMBER
Administration
REPORT
NUMBER
NAS A/TP--200
I-210992
20546-0001
11. SUPPLEMENTARY
NOTES
Prepared
for Structures
* AI Signal
12a,
and Dynamics
Research,
DISTRIBUTION/A
VAILABIL
Laboratory,
Science
and Engineering
Directorate
Inc.
ITY STA TEMEN_
12b. ITISTRIBUTION
CODE
Unclassified-Unlimited
Subject Category 15
Standard Distribution
13.
ABSTRACT
(Maximum
Engineering
interconnected
purpose
flight
200 words)
design
is a challenging
activity for
and have extreme energy densities,
of this document
transportation.
This baseline
can be used as a basis
characterization
discipline
is to delineate
and clarify
The goal is to define
is achieved
functions.
First,
any product.
their design
Since launch vehicles
represents
a challenge
the design
associated
and characterize
for improving
effectiveness
via compartmentalization
a global
design
process
process
a baseline
with the launch
for the space
and
The
vehicle
for space
design
process.
transportation
and efficiency
of the design
process.
The baseline
integration
of subsystems,
design
functions,
and technical
overview
are highly complex
of the highest order.
is provided
in order
to show
responsibility,
and
interactions.
and connectivity
of overall aspects of the design process. Then design essentials
are delineated in order to emphasize
necessary
features of the design process that are sometimes
overlooked.
Finally the design process characterization
is presented.
This
is accomplished
description
(technical
integration
design
sequence.
process,
a survey
Also included
by
model,
considering
subsystem
in the document
of recommendations
project
technical
framework,
tree, design/discipline
are a snapshot
from experienced
planes,
relating
practitioners
technical
decision
integration,
gates,
to process
improvements,
in aerospace,
lessons
process
and tasks),
and the
illustrations
of the
learned,
references,
and
a bibliography.
14.
SUBJECT
15. NUMBER
TERMS
design process, space transportation,
technical
integration,
launch vehicles
16. PRICE
17.
SECURITY
CLASSIRCATION
OF REPORT
Unclassified
NSN7S40-0t-280-SS00
18. SECURITY
CLASSIFICATION
19. SECURITY
CLASSIFICATION
OF THIS PAGE
OF ABSTRACT
Unclassified
Unclassified
OF PAGES
26O
CODE
20. LIMITATION
OF ABSTRACT
Unlimited
Standard Form 298 (Rov. 2-89}
Pre_cn'bedby ANSI Std, 239-18
298-102