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SpaceNet: Simulation Environment for Space Exploration Logistics. Future In-Space Operations (FISO) Telecon Colloquium October 26, 2011 at 3pm Eastern Time Prof. Olivier de Weck, Paul Grogan PhD candidate Massachusetts Institute of Technology. Outline. Introduction
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SpaceNet: Simulation Environment for Space Exploration Logistics Future In-Space Operations (FISO) Telecon Colloquium October 26, 2011 at 3pm Eastern Time Prof. Olivier de Weck, Paul Grogan PhD candidate Massachusetts Institute of Technology
Outline • Introduction • Challenges of Space Logistics • Time-varying launch opportunities • Nested complexity and object hierarchy • Asset management in m-gravity • SpaceNet Simulation Environment • Ontology of Space Logistics – Key Concepts • SpaceNet 2.5 – Discrete event simulation software • Four Application Case Studies • Conclusions
MIT Strategic Engineering Research Group (http://strategic.mit.edu) Research sponsors • Broad research agenda in Systems Engineering with a lifecycle focus Strategic Engineering is the process of designing systems and products in a way that deliberately accounts for future uncertainties and attempts to maximize lifecycle value. Ilities – A Definition The ilities are desired properties of systems that often manifest themselves after a system has been put to initial use. These properties are not the primary functional requirements of a system’s performance, but typically concern wider system impacts with respect to time and stakeholders than embodied in those primary functional requirements. O. de Weck A. Alfaris G. Bounova A. Siddiqi J.Agte D.Asai T. Coffee B.Baker S. Do T. Ishimatsu P. Grogan Ref: de Weck O., Roos D., Magee C., “Engineering Systems: Meeting Human Needs in a Complex Technological World”, MIT Press, Fall 2011) - Chapter 4 G. O’Neill C.Lee S. Nag S.W.Paek N.Shougarian K. Sinha H. Yue
Definition (http://spacelogistics.mit.edu) • Space logistics is the theory and practice of driving space system design for operability, and of managing the flow of materiel, services, and information needed throughout the space system lifecycle. Campaign Analysis Asset Management ISS Resupply In-Space Refueling Launch Logistics AIAA Space Logistics Technical Committee 2008-2010 In-Space Refueling
Challenges of Space Logistics Earth Mars: Time-varying Launch Opportunities Can only launch missions every ~ 26 months = time-expanded transportation. C3d Contour Plot [km2/s2] Ishimatsu T., Hoffman J., de Weck O.L., “Interplanetary Trajectory Analysis for 2020- 2040 Mars Missions Including Venus Flyby Opportunities”, AIAA-2009-6470, AIAA Space 2009 Conference & Exposition, Pasadena, California, September 14-17, 2009
Pocket Container Carrier Module Segment Compartment Element Pallet Assembly Facility* Node Vehicle Challenges of Space Logistics Supply Items M02 Bags MPLM Racks MPLM Cargo Integration MPLM In Shuttle Nested Complexity and Object Hierarchy • Item • Drawer • Kit • Locker • Unit • Rack • Lab • Platform • MPLM • Payload Bay • Fairing • Component • Subsystem • System • SRU • LRU • ORU • CTB • M-01 • M-02 • M-03 *In-Space Facility (e.g., the European Technology Exposure Facility (EuTEF) Net cargo mass fractions are very low (<1% of launch mass). Tare mass matters. Evans W., de Weck O., Laufer D., Shull S., “Logistics Lessons Learned in NASA Space Flight”, NASA/TP-2006-214203, National Aeronautics and Space Administration Technical Report, May 2006
Expedition 11 NASA ISS Science Officer John Phillips is working with cargo transfer bags inside the Quest Airlock
Challenges of Space Logistics Asset Management in m-gravity Tracking ~ 20,000 items Manual bar-code based system Relatively accurate system, but still ~ 3% of items are tagged as lost Space Requires substantial manual labor in space And on the ground (ISO) (>20’/day/crew) Earth Russian/NASA Inventory Management System (IMS) Automate real-time asset management. Track parent-child relationships. Shull S., Gralla E., de Weck O., Siddiqi A., Shishko R., “The Future of Asset Management for Human Space Exploration: Supply Classification and an Interplanetary Supply Chain Management Database”, AIAA-2006-7232, Space 2006, San Jose, California, Sept. 19-21, 2006
SpaceNet 2.5 Modeling and Simulation of Space Logistics A computational environment for • Modeling space exploration from a logistics perspective • Discrete event simulation • at the individual mission level (sortie, pre-deploy, re-supply,…) • at the campaign (=set of missions) level • Evaluation of manually generated exploration scenarios with respect to feasibility and measures of effectiveness • Visualization of the flow of elements, agents and supply items through the “interplanetary” supply chain • Optimization of scenarios according to selected MOEs • Provide software tool for users (= logisticians, mission architects) to support trade studies and architecture analyses. Open Source Release 2.5.2 Sep 2011 Under GNU General Public License http://spacenet.mit.edu
Building Blocks of SpaceNet • Nodes • Surface, Orbital, Lagrange • Objects • Supply Items, Elements, Crew (Agents) • Network (Time-Expanded) • Time-dependent Edges • Surface, Trajectory, Flight • Events • Create, Transfer, Remove, Reconfigure, Demand • Higher-level Processes (Transport, Exploration) Domain Simulator Nodes, Edges Alter State Read Events Events time = 4.2 MOE1 = 39.294 MOE2 = 198.339 Read State Add Events Elements, Supplies Grogan P., Armar N., Siddiqi A., de Weck O., Shishko R. , Lee G., “Object Oriented Approach for Flexibility in Space Logistics Discrete Event Simulation”, AIAA-2009-6548, AIAA Space 2009 Conference & Exposition, Pasadena, California, September 14-17, 2009
Case 1: ISS Resupply • Assembly nearly complete • Lifetime extended to 2020 or beyond • Most critical resupply vehicle retired (STS Shuttle) • Six or more vehicles to participate in ISS operations • Analyze scheduled supply versus estimated demands Grogan P.T., Yue H., de Weck O., “Application Case Studies for Flexible Space Logistics Modeling and Simulation using SpaceNet 2.5”, AIAA Space 2011 Conference & Exposition, Long Beach, California, September 27-29, 2011 Image credit: NASA
ISS Resupply Scenario Sept. 2010 – Dec. 2015: 77 missions 2 STS 22 Progress 22 Soyuz 12 Dragon 8 Cygnus 6 HTV 4 ATV 1 Proton-M
ISS Resupply Analysis Demands • 10 tons/year spares • 15 tons/year science • 7.5 kg/person/day consumables Results • Supply capacity exceeds demands • Existing stockpile can supply gaps • Frequent resupply missions (every 20 days)
Case 2: Lunar Outpost Campaign • Lunar south pole outpost buildup to continuous human presence • Based on NASA LSSPO / CxAT-Lunar Scenario 12 • Well-vetted case • Sufficiently detailed design • Surface mobility elements: • Lunar electric rover (LER) • Tri-ATHLETE Image credit: NASA
Lunar Outpost Scenario Sept. 2021 – Dec. 2028: 17 missions 2 sortie-style (1 un-crewed) 7 outpost-style 8 cargo resupply Excursions to Malapert Crater and Schrödinger Basin
Lunar Outpost Analysis • 7.5 kg/person/day consumables • 1000 kg/year ISRU oxygen production • 10% dry mass/year spares during crewed periods • 5% dry mass/year spares during un-crewed periods • Extra overhead mass for packaging (50-120% based on COS)
Case 3: Near-Earth Object Sortie • Evaluate 2-person, 5-day exploration at asteroid 1999-AO10 • Constellation-style heavy-lift launch vehicle • Increased upper stage propellant • Increased service module propellant • Greatly expanded cargo capacity • Significant assumptions: • No airlock in CEV • Zero-loss cryo-coolers • Restartable in-space stages • 7.5 kg/person/day demands including packaging mass Image credit: NASA
Near-Earth Object Scenario Sept. 2025 – Feb. 2026: 1 mission 2 crew members (7.5 kg/person/day demands) Upper Stage reused for Earth departure and 1999-AO10 arrival 5-day exploration at 1999-AO10
NEO Sortie Analysis • Small residual propellant values: • Upper stage: 0.1% • Service module: 0.2% • Limited volume and mass capacity in CEV • No ECLSS closure • Cryogenic fuel losses • No airlock for EVA exploration • Technically “feasible” though not realistic
Case 4: Mars Exploration Campaign • A “flexible path to Mars” • Four interchangeable missions • Use of propellant depots in Earth and Mars orbit • Human/robotic exploration • Pirogue vehicle for human exploration in the vicinity of Mars • Builds on concepts in NASA Design Reference Architecture 5.0 NASA/NIA 2010 RASC-AL Competition Winner Image credit: NASA
Mars Exploration Scenario 2034-2053: 4 flexible missions Mars Tele-exploration Mission (MTM) – 3 kg returned (hoppers) Phobos and Deimos Sorties (PDS) – 150 kg returned (Pirogue) Phobos Exploration Mission (PEM) – 150 kg returned Mars Surface Mission (MSM) – 250 kg returned
Conclusions • Space Exploration Logistics is challenging and distinct from terrestrial logistics • Key issues are launch windows, competition for manifest space, accommodation mass overhead .. • Need to move from individual missions to campaigns of integrated missions (also for purely robotic missions) • SpaceNet is a flexible and user friendly environment for integrated mission planning and logistics analysis
Questions? Acknowledgements: • NASA Exploration Systems Mission Directorate for funds for SpaceNet 1.3 development • Jet Propulsion Laboratory for support in developing SpaceNet 2.5 • DoD, Air Force Office of Scientific Research, National Defense Science and Engineering Graduate (NDSEG) Fellowship, 32 CFR 168a spacenet.mit.edu Image credit: NASA