Design Solution Definition Process
Design Solution
Definition
•
4
4
Requirement 18 (Section 3.2.4.1) “The Center Directors or designees
shall establish and maintain a process, to include activities,
requirements, guidelines and documentation, for designing product
solution definitions within the applicable WBS Model that satisfy the
derived technical requirements.”
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Design Solution Definition
Purpose
•
4
The Design Solution Definition Process is used to translate the
outputs of the Logical Decomposition Process into a design solution
definition
Design Solution
Definition: the
specification of a rocket,
for example
Figure 4.3-2 Example of a PBS
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Design Solution Importance
4
What we wanted
• Define solution space
• Develop design alternatives
• Trade studies to analyze
This image of a space shuttle has been
removed due to copyright restrictions.
– Alternate Design
– Cost, performance, schedule
• Select Design Solution
• Drive down to lower level
• Identify enabling products
What we got
This image of a space shuttle in a
building complex has been removed
due to copyright restrictions.
Design with the end in mind!
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Design Solution Questions
4
• What types of criteria are necessary to evaluate
alternate design solutions?
–
–
–
–
–
–
–
Does it meet technical requirements?
Is it compatible with the other system components?
How difficult is it to produce?
Can it be delivered within acceptable time frame?
How reliable will it be?
Which functions does this solution satisfy?
How easy will it be to operate?
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Design Solution Definition
4
• As alternative concepts are considered, the
Design Solution Definition Process includes:
– Transforming the defined logical decomposition
models and their associated set of derived technical
requirements into alternative solutions
– Fully defining the selected alternative(s) into a design
solution definition that will satisfy the technical
requirements
• This process is repeated at lower levels as
additional subsystems need to be defined
3.2.4.2 – Design Solution Definition Purpose
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Design Solution Methods
4
• Group and Partition functions with system elements
System
Functions
Physical
Elements
Launch
Vehicle
Avionics
X
X
Guide
Deploy
Solar
Array
Fuel Cell
Antenna
X
X
Communicate
Power
X
X
X
X
Recover
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Trade Study Process
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Important Design Considerations
Capabilities
Functions
System
Performance
Priorities
Technical
Effectiveness
Reliability
Maintainability
Supportability
System
Availability
4
Other Considerations
• Software
• System Safety
• Accessibility
• Information Assurance
• COTS
• Disposal
• Human Factors
• Environ. Constraints
System
Effectiveness
Producibility
Operations
Maintenance
Process
Efficiency
Affordable
Operational
Effectiveness
Logistics
Life Cycle Cost/Total Ownership Cost
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Design Solution Methods
4
• Analyzing each alternative to be able to select
the preferred alternative
• Once an alternative is selected or baselined, the
Design Solution Definition Process will be used
for:
– Generating end products as a function of the
hierarchy in the system structure
• The output end product Design Solution
Definition will be used for conducting product
verification
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Ares V Interfaces and Elements
Altair Lunar Lander
Gross Lift Off Mass: 3,704.5 t (8,167.1k lbm)
Integrated Stack Length: 116 m (381 ft)
Payload Adapter
Payload
Shroud
4
J–2X
Loiter Skirt
Interstage
Solid Rocket Boosters (2)
• Two recoverable 5.5-segment
PBAN-fueled, steel-casing
boosters (derived from current
Ares I first stage
Earth Departure Stage (EDS)
• One Saturn-derived J–2X LOX/LH2
engine (expendable)
• 10 m (33 ft) diameter stage
• Aluminum-Lithium (Al-Li) tanks
• Composite structures, Instrument Unit
and Interstage
Core Stage
• Primary Ares V avionics system
• Six Delta IV-derived RS–68B LOX/LH2
engines (expendable)
• 10 m (33 ft) diameter stage
• Composite structures
• Aluminum-Lithium (Al-Li) tanks
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Two representative configurations shown
Multiple configurations for adding a 6th
Engine being traded
RS–68B
Engines
(6)
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Open Systems & Enabling Product
4
• A system that implements
specifications maintained by an
open, public consensus process
for interfaces, services, and
support formats, to
– Enable properly engineered
components to be utilized
across a wide range of
systems with minimal
change,
– Interoperate with other
components on local and
remote systems, and
– Interact with users in a
manner that facilitates
portability
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Design Solution Outputs
Technical Data
Package
includes:
•
•
•
•
Specifications
Drawings
Sketches
Parts list
Specific descriptive
documentation for
buying, building,
coding or
assembling
& integrating end
products is a
function of lifecycle phase and
location of WBS
model in the system
structure
4
System
Specification
•••
End
Product
Development
Products
Fabrication
Integration
Assembly
products
Test
Products
Operations
Products
Logistics
Products
•••
Subsystem
Subsystem
Subsystems:
Initial
Specifications
for development of
next lower level
WBS models
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Enabling Products:
Expectations for initiation
of development or
procurement/reuse of
enabling products
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Modeling and Simulation (M&S)
4
• Can be an important tool for design process
(Provided that models are sufficiently adequate
descriptions of reality – they are valid)
– Better understand and optimize performance
• Multiple combinations and permutations
– Fly or test more effectively early in the design
• More experimentation and data generation without costly
prototypes and tests
• Can save Time and Resources.
• Requires Experience and Skill
M&S is used as a tool throughout the
Systems Engineering Process
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Benefits of a Designing the
Right system
4
• Meets stakeholder
expectations
• Meets
cost/schedule and
performance
requirements
• Operates as
specified in
ConOps
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Design Solution Definition – Best
Practice Process Flow Diagram
Activities
4
Output
Input
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Summary
4
• The Design Solution Definition Process is used to
translate the outputs of the Logical Decomposition
Process into a design solution definition
• Alternative design solutions must be defined and
analyzed to select the best alternative that satisfies
technical requirements
• The form of the design solution definition depends on the
product life cycle phase and its hierarchy in the system
• The Technical Data Package allows for the building,
coding, reusing, or buying of products
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Technical Solution Definition
4
Discussion
• Where in the Solution Definition Process do we
tend most to skip steps (where we should not)?
• Do tight schedules mean we scrimp in the wrong
places?
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MIT OpenCourseWare
http://ocw.mit.edu
16.842 Fundamentals of Systems Engineering
Fall 2009
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