Gateway To Space
ASEN 1400 / ASTR 2500
Class #17
Colorado Space Grant Consortium
T-39
Today:
- Announcements
- One Minute Report Questions
- Guest Lecture on Systems Engineering
Announcements:
- Hardware for teams…
- Pressure sensors and other hardware UNO $$$
- Latest grades posted later today
- Feedback on DD Rev A/B next Tuesday
- DD Rev C assigned today and due 11-16-12
- Don’t forget about HW #8 – Review it first
Announcements:
- Traveling tomorrow – Planned
- Guest speaker is not coming – Not Planned
- So tomorrow is…
Next Time…
Spider
Plus remote introduction
(Originally the lecture scheduled
for November 15th)
Colorado Space Grant Consortium
One Minute Report Questions:
- What kind of rocket is Dreamchaser?
- What is Dreamchaser used for?
- Where do dropped engines go? Orbit, outerspace?
- Biggest advance from past to present rockets?
- Do all space programs work together now?
- How do private companies get funded?
One Minute Report Questions:
- Why do they chose solid vs. liquid, vs. hybrid?
- As an aerospace major, how well versed should I be
with coding/programming?
- What happened to the Orion space missions?
- What does the future of space exploration look like?
Questions?
Colorado Space Grant Consortium
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Homework #7
Review
Colorado Space Grant Consortium
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Homework #7:
NASA Mission Announcement – ChuSat
Design a spacecraft in 30 minutes that will meet the following
two requirements:
1.
The total mass of the power, science instruments, and
propulsion shall not exceed 900 lbm.
a.
The propulsion mass shall include the mass of
propellant
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Homework #7:
NASA Mission Announcement – ChuSat
Design a spacecraft in 30 minutes that will meet the following
two requirements:
2.
The spacecraft shall collect a minimum of 20 hours of
scientific data
a.
The spacecraft shall collect data in the 1x10-9 to
1x10-10 wavelengths
b.
The spacecraft shall collect data in the 1x10-3 to
1x10-4 wavelengths
The following subsystem capabilities and specifications are at
your disposal.
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Homework #7:
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Homework #7:
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Homework #7:
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Homework #7 - (Answer)
Science
- Infrared Sensor
- X-ray Sensor
Total Science Mass
75 W
100 W
30 lbm
40 lbm
70 lbm
If only one sensor is on at a time is the requirement of 20 hours
met?
Only have one sensor on at a time, therefore the Science power
requirement is 100 W, not 175 W.
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Homework #7 - (Answer)
Power
Need at least 1,000 W to stay alive plus 100 W for science
therefore you need to have at least 1,200 W solar array and
battery
Total weight = 60 lbm for solar array
= 120 lbm for battery
Total = 180 lbm
You will find out the Fuel cell is way too heavy
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In-Class Exercise: (Answer)
Propulsion
Need at least 80 lb of thrust therefore you need the following
Two 25 lb thrusters
Three 10 lb thrusters
= 20 W
= 20 W
25 lbm
15 lbm
Total Power
Total Mass
= (40+60 W) = 100 W
= (25+25+15+15+15) =95 lbm
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In-Class Exercise: (Answer)
Total Mass
Science
Power
Propulsion
Total
= 70 lbm
= 180 lbm
= 95 lbm
= 345 lbm (minus propellant)
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In-Class Exercise: (Answer)
Propellant Mass
2x25 lb = 50 per/100 lbm
3x10 lb = 20 per/100 lbm
Total
= 100 lb
= 60 lb
= 160 lb per 100 lbm
345 lbm / 100 lbm * 160 lbm = 552 lbm
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In-Class Exercise: (Answer)
Total Mass
Science
Power
Propulsion
Total
= 70 lbm
= 180 lbm
= 95 lbm
= 345 lbm (minus propellant)
Propellant
= 552 lbm
Total mass
= 897 lbm
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Systems Engineering
Jessica Brown
Lockheed Martin
Rachel Landess
Lockheed Martin
Colorado Space Grant Consortium
Introduction to Systems
Engineering
October 23, 2012
Rachel Landess
Keith Morris
Jessica Brown
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What is Systems Engineering
• Is a systematic, interdisciplinary approach
that transforms customer needs into a total
system solution
• A framework of interrelated activities that
spans Design, Management, and
Realization of systems
• Balances customer needs with system
capabilities
• Led and organized by Systems Engineers
– But all functions play a role
• It is the technical “glue” which makes
separate design disciplines and
subsystems function together to provide an
integrated system
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Be a “Systems Thinker”
• The Design Engineer
– The specialist's viewpoint
– Views the system from the inside
– Concerned with other system elements
only as they affect their own design task
– Not necessarily how their system may
affect others
• Systems thinkers
– Views the system from the outside.
– Concerned with the effect of all system
elements as they affect overall system
design / performance / cost / schedule
– Concerned no matter where the hole in the
boat is
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Systems Engineering must focus on the entire problem:
optimize the whole, not the parts!
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The Art & Science of Systems Engineering
• Art of Systems Engineering
– Technical Leadership
– Understanding how all the individual
pieces go together to make the big
picture
• Science of Systems Engineering
– Systems Management
– Managing all the details for every
piece of the system and keeping
them in synch
• Cost, Schedule, Performance, &
Risk
To be Successful, we must balance both technical leadership
and systems management into complete systems engineering
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Systems Engineering “V” Model
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Architecture
• System Architecture is the overall structure of the program, internal
interfaces, and how it interacts with external interfaces
– System Level – Constellation of Satellites, Ground stations, etc.
– Spacecraft Level – Subsystems and interfaces that make up
spacecraft
– Subsystem – Components and technologies that make up subsystem
– Architect’s role is to ensure customer requirements and needs are
properly addressed in the system
• Identifies utility and flexibility of the system
• Optimizing architecture can make spacecraft trades easier
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Spacecraft Architecture
(image credit: NASA/GSFC)
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Concept of Operations
• Concept of Operations (CONOPS)
– How the system will be used
– Links technical requirements with user’s needs
• Requirements do not fully represent customer’s wishes…
– Operational scenarios, timelines, block diagrams, orbital
maneuvering among the products
– Example: Assignment Requirements do not specify how often
payloads need to operate, could reduce overall power required
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Con Ops Example – ALL-STAR
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Requirements Management
• A requirement is a “single, verifiable
shall statement”
• Requirements dictate the form, fit
and function the system design shall
Level 0
meet
(Mission)
• Requirements address both
characteristics as well as
Level 1
(System)
capabilities
– Characteristics=what the system
Level 2
shall be
(Subsystem)
– Capabilities=what the system
shall do
Level 3
(component
• Higher level requirements are
decomposed to lower level
requirements
3.0 Mission shall
consist of...
3.1 System shall
interface to...
3.2 System shall
interface to...
3.3 System shall
provide...
3.1.1 Subsystem
shall provide...
3.1.1.1 Component
shall consist of...
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Why are requirements important
How the customer
explained it
How materials
ordered it
How the project
manager understood it
How it was built
How the engineers
designed it
How the customer
really wanted it
Clearly communicating requirements is essential
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Design Integration
• Balance the needs of the customer with the
capabilities of the spacecraft
• Balance the needs of the individual subsystems
– Allocate mass, volume, power constraints
– Relate it to their assignment
• Ensuring subsystems are talking with one another
– Making sure they are compatible
• Identifying subsystem interfaces
Its kind of like
Herding Cats
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Risk Management
Risk Matrix
Probability of Occurrence
• Risk management is done throughout the entire
program life cycle
• Risk is defined in two dimensions
– Probability of occurrence
– Consequence if the risk occurs
• Identify risks while there is still time to react
• Put in place mitigation strategy to minimize or
eliminate risks
• Sources of risks include:
– Poorly defined technical tasks or cost
estimations
– Poorly defined requirements and interfaces
– Low technological maturity (technical risks)
– Unrealistic project planning or inadequate
resources
– Inadequate workforce skill level
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3
2
1
1
2
3
4
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Consequence
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Hardware Integration
• Assembly of spacecraft hardware
Spitzer Space Telescope from design to integration
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Verification and Validation
• Verification
– “Did we build the system right”
• Validation
– “Did we build the right system”
• System Testing
– Functional tests
– Vibe tests (drop tests)
– Shock tests (swing tests)
– Thermal Vacuum tests
– Acoustic tests
ALL-STAR and team at vibe test at
Lockheed Martin
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Mission Operations
• Starts when spacecraft development is
initiated and continues through final
disposal of space asset
• Provide mission requirements support for
development of operational systems
– Used to plan and control launch vehicle
and spacecraft operations
• Developing mission profiles, operational
procedures and related operational
documentation
• Balance and allocate operational
requirements with operational performance
• Determine operations integration tasks
– Defining capabilities and constraints
associated with launch vehicles,
spacecraft and mission control and
ground systems
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Summary
• Systems Engineering is an integrated composite of
people, products, and processes
– Forms a structured development process
– Spans design, production, and operation of systems
• Balances the needs of the customer with the
capabilities of the system
• Uses technical leadership and systems management
– Integrates all disciplines and specialty groups into
team
– Manages cost, schedule, performance, and risk
• There is no perfect solution
– Systems engineering produces the optimal solution
for the entire spacecraft
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