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Space Systems ArchitectureLecture 3
Introduction toTradespace Exploration
Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
Hugh McManusMetis Design
Space Systems, Policy, and Architecture Research ConsortiumA joint venture of MIT, Stanford, Caltech & the Naval War College
for the NRO
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• A process for understanding complex solutions to complex problems• Allows informed “upfront” decisions and planning
Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
Tradespace Exploration
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• Model-based high-level assessment of system
capability
• Ideally, many architectures assessed
• Avoids optimized point solutions that will not
support
evolution in environment or user needs
• Provides a basis to explore technical and policy
uncertainties
• Provides a way to assess the value of potential
capabilities Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
Architecture Trade Space Exploration
A process for understanding complex solutions to complex problems
Allows informed “upfront” decisions and planning
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• State-of-the-art rapid preliminary design method
• Design tools linked both electronically and by co-
located
humans
• Design sessions iterate/converge designs in hours
• Requires ready tools, well poised requirements
Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
Integrated Concurrent Engineering
A process creating preliminary designs very fast
Allows rapid reality check on chosen architecturesAids transition to detailed design
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• Linked method for progressing from vague user
needs to
conceptual/preliminary design very quickly
• MANY architectures, several/many designs
considered
• Understanding the trades allows selection of robust
and
adaptable concepts, consideration of policy, risk.
Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
Emerging Capability
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Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
What is an Architecture Trade Space?
X-TOS• Small low-altitude
science mission
Each point isa specific
architecture
DESIGN VARIABLES: The architectural trade parameters
• Orbital Parameters – Apogee altitude (km) 150-1100 – Perigee altitude (km) 150-1100 – Orbit inclination 0, 30, 60, 90
• Physical Spacecraft Parameters – Antenna gain – communication architecture – propulsion type – power type – delta_v Assessment of the utility and cost of a large
space of possible system architectures
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Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
Developing A Trade Space
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Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
XTOS Tradespace Development
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Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
Continued
Pareto front of “best”architectures
Each point is aspecific architecture
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Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
Understanding What Systems Do
• Transmit Information• Collect Information• Move Mass (inc. People)• Others (Space Station…)
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Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
StakeholdersUnderstanding who cares -
• Many interested parties in a complex system
• Each “customer” has a set of needs
• They are different, and can be contradictory
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Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
Concept Selection: Bounding
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Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
Scoping
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Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
Attribute
• “what the decision makers need to consider”
• ( and/or what the user truly cares about)
• Examples: Billable minutes = GINA metrics
• TPF Pictures = camera performance metrics
• Rescue/move satellites = mass moving, grappling capability, timeliness – Could have sub-cartoons for above
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Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
XTOS Attribute
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Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
Utilities
• “What the attributes are WORTH to the
decision
makers”
• Single Attribute utility maps attribute to utility
• Multi-attribute utility maps an architecture (as
expressed by its attributes) to utility
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Single Attribute Utilities
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Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
Multi-Attribute Utilities
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Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
XTOS Design Vector
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Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
ATOS Design Vector
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Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
Scoping-QFDs
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Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
Scoping-Iteration/evolution
Swarm type Concept type Swarm perigee altitude Swarm perigee altitude# sats/swarm # sats/swarm Swarm apogee altitude Swarm apogee altitude# swarms # swarms per plane # sats/swarm # sats/swarmSwarm orbit # orbital planes # subplanes/swarm # subplanes/swarm Intra-swarm orbit Swarm altitude # suborbits/subplane # suborbits/subplaneInstrument type Swarm orientation Yaw angle of subplanes Yaw angle of subplanes# instruments/sat Swarm geometry Max sat separation Max sat separationTT&C scheme Separation within swarm Mothership (yes/no)Ground station Mothership (yes/no)Mission lifetimePosition control schemeProcessing schemeLatitude of interest
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Mapping Design Vector to Attributes
and Utilities - Simulation Models
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Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
Techsat ModelsInputs (Design Vector)
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Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
Exploring the Tradespace
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Space Systems, Policy, and Architecture Research Consortium ©2002 Massachusetts Institute of Technology
The Pareto Front
• Set of “best” solutions
• “Dominated” solutions are more expensive or less
Capable
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Optimization
• Can look for the Pareto front using advanced
optimization techniques
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Using the Trade Space to Evaluate
Point Designs