SpaceNet: Simulation Environment for Space Exploration Logistics Future In-Space Operations (FISO) Telecon Colloquium October 26, 2011 at 3pm Eastern Time.

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

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Outline

• Introduction• Challenges of Space Logistics

– Time-varying launch opportunities– Nested complexity and object hierarchy– Asset management in -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)

• Broad research agenda in Systems Engineering with a lifecycle focus

© Olivier de Weck, October 2011 Page 3

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.

Research sponsors

J.Agte D.Asai T. Coffee S. Do P. Grogan T. Ishimatsu

C.Lee S. Nag N.ShougarianG. O’Neill S.W.Paek K. Sinha H. Yue

A. Alfaris A. Siddiqi G. Bounova

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.

Ilities – A Definition

Ref: de Weck O., Roos D., Magee C., “Engineering Systems: Meeting Human Needs in a Complex Technological World”, MIT Press, Fall 2011) - Chapter 4

B.Baker

O. de Weck

• 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.

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LaunchLogistics

ISSResupply

In-SpaceRefueling

CampaignAnalysis

Asset Management

AIAA Space Logistics Technical Committee 2008-2010

Earth Mars: Time-varying Launch Opportunities

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

Can only launchmissions every~ 26 months = time-expanded transportation. C3d Contour Plot [km2/s2]

Challenges of Space Logistics

Nested Complexity and Object Hierarchy• Pocket• Container• Carrier• Module• Segment• Compartment• Element• Pallet• Assembly• Facility*• Node• Vehicle

• 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)

M02 Bags

SupplyItems

MPLMRacks

MPLMCargoIntegration

MPLMIn Shuttle

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

Challenges of Space Logistics

Expedition 11 NASA ISS Science Officer John Phillips is working with cargo transfer bags inside the Quest Airlock

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Asset Management in -gravity

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Bar Code R eader

Multiple SSC/NGL

Clients

SSC/NGL File Server

DB

Communication occurs via Radio Frequency (RF) and is relayed through the RF Access Point located in the LAB

OCA Up

OCA Dow n

SSC/NGL Client

OCA Router

Tracking ~ 20,000 items

Manual bar-code based system

Relatively accurate system, but still ~ 3% of items are tagged as lost

Requires substantialmanual labor in spaceAnd on the ground (ISO)(>20’/day/crew)

Russian/NASAInventoryManagementSystem (IMS)

SpaceEarth

Automate real-timeasset 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

Challenges of Space Logistics

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SpaceNet 2.5 Modeling and Simulation of Space Logistics

• 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.

A computational environment for

http://spacenet.mit.edu Open Source Release 2.5.2 Sep 2011Under GNU General Public License

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)

Slide 10

EventsSimulator

Nodes, Edges

Elements, Supplies

Domain

time = 4.2MOE1 = 39.294

MOE2 = 198.339

Read Events

Add Events

Alter State

Read State

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

Slide 11

• 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

Case 1: ISS Resupply

Image credit: NASA Slide 12

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

Slide 13

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

Slide 14

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)

• 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

Case 2: Lunar Outpost Campaign

Slide 15Image credit: NASA

Slide 16

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

Slide 17

• 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)

• 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

Case 3: Near-Earth Object Sortie

Slide 18Image credit: NASA

Slide 19

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

Slide 20

• 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

• 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

Case 4: Mars Exploration Campaign

Slide 21Image credit: NASA

NASA/NIA 2010 RASC-AL Competition Winner

Slide 22

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

Slide 23

Mars Exploration Campaign Bat Chart in SpaceNet

Mars Exploration Analysis

Slide 24

Figure of Interest MTM PDS PEM MSMCampaign

TotalsAres V launches (mission payloads) 2 2 2 4 10Ares V launches (PRM payload) 6 6 6 11 29Crew launches 1 1 1 1 4Total mass in LEO (mT) 681.7 681.7 681.3 1,448.7 3,493.4Number of sites sampled 3 2 1 1 5Returned sample mass (kg) 3 150 150 250 553EDS propellant usage (mT) 510.9 510.9 511.9 1,019.1 2,552.8EDS propellant remaining (mT) 4.7 4.7 4.8 47.3 61.5Crew consumables demand (mT) 12.5 12.5 12.5 15.3 52.8Crew consumables remaining (mT) 1.2 1.2 1.2 12.3 15.9Robotic-days of exploration (robot-days) 360 0 0 1,060 1,420Human-days of exploration (human-days) 0 28 360 2,120 3,568

Overview of SpaceNet Modeling Flexibility

Slide 25

ISS Resupply

Lunar Outpost

NEO Sortie

Mars Exploration Campaign

Nodes 9 5 4 10

Edges 13 6 3 23

Missions 78 17 1 21

Events 271 156 6 337

Elements Types 14 30 11 32

Elements 90 140 12 234

Duration (days) 1,920 2,628 148 6,911

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

Slide 26

Slide 27Image credit: NASA

Questions?

spacenet.mit.edu

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