1. Servicing Study Notional Mission Interim Status Satellite Servicing Study Ben Reed Benjamin.B.Reed@nasa.gov Jackie Townsend Jacqueline.A.Townsend@nasa.gov

2. Notional Mission Paradigm Space Servicing Capabilities Project, Astrophysics Projects Division at Goddard Space Flight Center is responding to a Congressional directive to study the assess the feasibility, practicality and cost of servicing satellites using elements of currently planned and future NASA human spaceflight systems and/or robotic technologies. This work is in support of recommendations by the National Research Council, NASA’s Authorization Act of 2008 (Public Law 110-422) and the FY2009 Omnibus Appropriations Act. A suite of notional missions was developed that would sample the trade space of satellite servicing as broadly as possible. We intentionally want to poke into the unsampled corners. The notional missions were also chosen to explore the technology need commonalities between them. This will lead to a technology gap assessment in the final report. Where possible existing satellites and launch vehicles are employed in the design process. Each notional mission will be designed by the unique combination of the Hubble Space Telescope (HST) servicing team and the Integrated Design Center (IDC) at GSFC. The IDC is a multi-discipline engineering design “think tank” that builds complete mission concepts from simple ideas.

3. Notional Mission Suite NM1NM2NM3NM4NM5NM6 SuperSyncGeoFuelLEO Refurb-COTSEM AssemblyHEO Human Refurb SE Human (Hab) Assembly OrbitGEO LEOEML1HEOSEL2 Service despin, orbit adjust (robotic) fluid transfer (robotic) ORU swap (human + robot) complex assembly (robotic) refurbishment (human + robot) assembly (human + robot) Customer (mass) uncontrolled GEO satellites (5000 kg, ~10 total) GEO satellites w/ monoprop (5000 kg) existing observatory designed for servicing (11,000 kg) 30 m telescope (20,000 kg) 9.2 m telescope (15,700 kg) 20 m telescope (TBD kg) Mission Duration9 days per customerone week per customer 2 days EVA, 4 weeks EVR 24 months EVR10 days EVA/EVRTBD Prox Ops AR&C of spinning, non-coop AR&C of non-coop customer, AR&D w/ tanker AR&D to HST, cap & berth of COTS AR&D with barges Cap & berth w/ barges and Orion TBD Robot Arms6 m 14 m, 7 m, distributed control Reconfigurable arms, walk-about 20 m grapple arm, 2 m dexterous pair TBD Dry Mass (kg)2,300 1,500 + 2,200 kg prop to customers 12,000 (+ 3,600 SI/ORU) 12,000TBD

4. Notional Missions As part of NASA GSFC’s Satellite Servicing Study, suite of notional missions was developed that would sample the trade space of satellite servicing as broadly as possible. Where possible existing satellites are employed in the design process. Each notional mission will be designed by the unique combination of the Hubble Space Telescope (HST) servicing team and the Integrated Design Center (IDC) at GSFC. The IDC is a multi-discipline engineering design “think tank” that builds complete mission concepts from simple ideas. 1.Robotic capture, reposition to supersync orbit, and release GEO non-functioning and functioning non-cooperative satellites 2.Robotic capture, refuel, and release GEO functioning non-cooperative satellites 3.Robotic assembly of large cooperative observatory at EML2 then deploy to SEL2 Additional notional missions are being developed that will explore the broadest areas feasible within the trade space including: –Target location, attitude, design, task complexity, robotic and/or EVA, etc.

5. Notional Mission 1 Study Summary Geo-Supersync Notional Mission: Develop a Servicer to autonomously rendezvous and dock with customer satellites in GEO and relocate them to a super-synchronous disposal orbit. Servicer incorporates an autonomous rendezvous and capture (AR&C) system consisting of a sensor suite, control electronics and robotic arms actuated via supervised autonomy. Requirement: 5-year design life and at least 10 disposal sorties. Customers are non-cooperative: not designed for servicing and may be uncontrolled or tumbling. Servicer comprised of Spacecraft Bus and Payload elements –Servicer bus design: Class B full redundancy – contractor –Payload elements: AR&C system (sensors, control electronics) - GSFC Robot system system (2 – 4 arms, control electronics) – GSFC –Integration of bus and payloads – GSFC Launch January 2015 –Launch to GSO, into plane of first Customer satellite –Move to Customer –Rendezvous and Capture Customer –Boost to Super-Synchronous Orbit: Geo + 350 km –Release Customer and return to Parking orbit –Drift to next Customer

6. Raise to Parking Orbit Mission Overview GEO Orbit Parking Orbit GEO + 300 km Drift to Cust. (3.8 °W/day) Lower to GEO (FarField) Raise to SuperSynch SuperSynch Orbit GEO + 350 km Delivery to GEO by ELV  V to first customer 59 m/s  V to first customer 59 m/s Lower to Parking Orbit Release Customer Drift to Next Customer (3.8 °W/day) AR&C

7. Overall Operations Concept

8. Final Rendezvous Profile

9. Spacecraft Bus Requirements Maneuver in Geostationary orbit to proximity of target (~200km) Sufficient agility to rendezvous with and capture targets with rotation rates up to.25 º per sec (all axes simultaneously) Provide the ability of the AR&C payload to direct the S/C GN&C system during Autonomous Rendezvous and Capture phase Provide the ability to maneuver the target to super synchronous disposal orbit (NASA-STD-8919.14) Provide electrical power, commanding, data downlink, thermal control, and structural support for the payload –Provide very low latency data to the payload operations center during AR&C operations –Provide adequate power during all phases of the mission, including capture phase, where solar arrays might not be illuminated Provide adequate expendable resources to perform 10 sorties in 5 years (two times per year)

10. Servicer (S/C) Component Layout

11. Specialized Servicer Elements (Payload) Autonomous Rendezvous and Capture Package Cameras LIDAR Laser Rangefinders 141 kg Robot Arms (2 - 4 total) 7 DOF Cameras and LIDAR in End Effector 615 kg for 4 arms

12. Servicer with Robotic Arms Layout

13. Servicer Satellite Concept

14. Customer Satellite Assumptions First customer: DSP –Uncontrolled and non-cooperative (not designed for servicing) Configuration –Non-cooperative (no retro-reflectors or other targets) –dry mass = 2,115 kg total mass = 2,277kg –Orbit altitude: 22,000 miles (35,900 km) –Power plant: Solar arrays generate 1,485 watts –Height: 32.8 ft (10 m) on orbit; 28 ft (8.5 m) at launch –Diameter: 22 ft (6.7 m) on orbit; 13.7 ft (4.2 m) at launch –Fuel in satellite at launch: 382 lbs monopropellant

15. 32.8 FT 22.95 FT Customer Satellite Mass ~ 2300 kg Tumble Rate ~0.05 deg/sec (solar radiation pressure dominates tumble rate)

16. Docked Configuration

17. Launch Vehicle Atlas V 551 3960 kg capability to GSO Atlas V 551 Short Fairing

18. Geosynchronous Satellite Refueling 18

19. Mission Study Summary Capture and refuel multiple Customers in Geostationary orbit 5 years to transfer ~2000 kg of fuel Servicer and Depot designed for 10 year life Size Servicer and Depot to launch aboard Delta IV (4050H-19) Servicer designed to allow consumable replenishment by future Depots Payload Elements –Automated Rendezvous and Capture System (sensors, control electronics) –Robot System (2 arms, control electronics) –Refueling package (end effectors/tools, fuel transfer hose) Customer Assumptions –3 axis stabilized –Can assume free drift mode –No retroreflectors –Fill and drain valve was not designed for on-orbit refueling –Monoprop (hydrazine) delivered –No pressurant delivery 19

20. Overall Lifecycle Launch 5 Campaigns to 30 Customers Approach & Capture Launch LV Separation Insert into GEO+100 Rate Null Sun Acquisition Servicer SA Deploy Burn to InterceptCustomer Capture Servicer: HGA Deploy Systems Checkout RAs CGAlign Commissioning For Each Customer: Enter Safety Ellipse Survey Customer Prepare Servicer for Approach & Capture Depot: Deploy solar sail Separate from Servicer Stay at GEO+100km Every 6 Customers, return To Depot, refuel, and adjust orbit Disposal GEO + 300 km Refuel Prepare Customer Maintain battery charge Transfer Fuel Closeout Depart 20

21. Post Vane Deploy Prior to Separation Refueling Servicer at Depot between Campaigns Mission Phases 21

22. Servicer vs. Depot Summary Mechanical – composite truss design, composite/Al honeycomb decks Thermal – MLI, heaters, thermistors, etc (TRL = 9) Comm – S band Omni, X band HGA, 10 Mbps downlink EPS – 7.2 m2 SA, dual axis SA drives, 200 Ah battery ACS – thruster based, star tracker, IRU, CSS, GPS Propulsion –monoprop Hz and cold gas N2 systems Avionics – 200 MIPs, 370 Gb onboard storage Payload – updated ARnC (no pan/tilt, extra cameras), 2 Robot Arms, 2 toolboxes Depot (minimal subsystems) Mechanical – composite truss design, composite/Al honeycomb decks Thermal – MLI, heaters, thermistors, etc (TRL = 9) Comm – none EPS – 0.9 m2 SA, no battery ACS – passive nutation damping, deployable solar sail Propulsion – none Avionics – heater controls, dormant electronics box becomes active during refueling Payload – 6 Toolboxes, Retro-reflectors Servicer 22

23. Timeline Overviews Customer 1 Undock from Depot Customer 2 Customer 3 Customer 4 Customer 5 Customer 6 Redock with Depot Campaign 1 Launch Self Disposal Rendezvous and Capture Start Refuel Recharge Batteries Finish Refuel Recharge Batteries Separate and move to next Customer 1.Overall Lifecycle Launch, 5 Campaigns, disposal 2.Each Campaign Fuel 6 Customers, adjust depot orbit as necessary 3.Customer Rendezvous and Refuel ARnC Prepare for fuel transfer Recharge batteries Transfer fuel (4 hours)(Up to 38 days)(4 hours)(3 hours)(4 hours)(~ 6 days) Customer must assume rendezvous configuration before capture 3 timelines: Campaign 2 Campaign 3 Campaign 4 Campaign 5 23

24. Notional Refueling of Customer 24

25. Notional Mission 3 MDL Study April 12 thru 16, 2010 Combined Robotic and Human Servicing of Satellite in Low Earth Orbit

26. Study Summary Single crewed spacecraft, single payload launch, human rated portions of payload spacecraft Design a mission to autonomously rendezvous and capture a known cooperative satellite in Low Earth Orbit and service it via teleoperations –Design Dexterous Servicing Module (DSM) and mission Customer satellite has known target & docking features DSM provides target docking features to allow Commercial Orbital Transportation Services (COTS) crew vehicle to dock to it –Identify mission operations, ground operations, and launch options

27. Mission Requirements Maneuver into LEO orbit in proximity to cooperative target at 560 km x 28.5 o orbit –After all servicing completed, reboost target to 615 km, and maintain deorbit reserve for combined stack if unable to undock from target Provide active autonomous rendezvous and capture with passive target –Control the stacked configuration Provide for autonomous rendezvous and crew controlled capture with Commercial Orbital Transportation Services (COTS) spacecraft –Control the stacked configuration; crew has authority to move stack & abort Provide consumable resources, electrical power, commanding, data downlink, thermal control, and structural support for robotic and EVA servicing operations –Service one target once and dispose of itself –Shade EVA worksite on HST from the Sun –2 EVA days (9 hrs/day) plus 1 contingency EVA day, assume 4 crew (2 in / 2 out) –5 days COTS attached to the DSM (4 plus 1 contingency) –Provide power to target during EVA servicing Provide electrical power, commanding, data downlink, thermal control, and structural support for all payloads Human rated mission – One fault: remain operational. Two faults: fail-safe where required to prevent catastrophic hazards to the crew. Crew able to abort and return home at any time. –DSM not required to actively support crew abort sequence Launch date based on 7/2011 Phase B start

28. Target Satellite Decision Hubble Space Telescope was utilized for requirements development –Few (if any) opportunities exist for LEO targets with as large a menu for interfaces and servicing needs –Provides known tool-tool interfaces –Provides known man-spacecraft interfaces –Provides excellent opportunities for exploring “worse case” scenarios, e.g. keep-out & “no-touch/no-damage” zones, plume impingement, thermal limits for change-outs, work site limitations & obstacles, etc. History of tool/technique development –HST is a proven test bed for LEO on-orbit repair and refurbish –HST has set standards for tool development over five servicing missions –Lessons learned regarding EVA technique have been applied to other (ISS) space missions –Demonstrated history of accomplishing what “can’t be done”

29. Concept of Operations Launch & Checkout Launch LV Separation Orbit Insertion SA & HGA Deploy Systems Checkout DSM Separates and Deorbits DSM EVR Work & Re-boost DSM robotic arms finishes servicing tasks DSM re-boosts HST AR&D & Pre-Servicing Preparation DSM direct docks with HST DSM controls of HST/DSM stack DSM performs worksite preparation EVA-EVR Servicing Crew performs two EVAs 2 Robotic arms assist crew during EVA & prepares worksite for next EVA overnight DSM Rendezvous/Grapple/Berth DSM grapples Dragon & berths DSM control of COTS/HST/DSM stack Dragon supplies own power & comm DSM supplies power & comm for DSM/HST COTS Separates and De-orbits

30. Maneuver Operations Concept: HST Capture Target Orbit Altitude = 537.5 km 5 km Co-Elliptic Orbit HST – 5.0 km Hubble Orbit Altitude = 560 km ARnD –3  Target Orbit Altitude = 530 km  V 10 m/s + 6 m/s (3  )  V 2 m/s 1.5 km Co-Elliptic Orbit HST – 1.5 km  V 23 m/s

31. Maneuver Operations Concept: Re-Boost & De-Orbit Hubble Orbit Altitude = 560 km Re-Boost Orbit Altitude = 615 km De-Orbit 50 x 615 km  V 30 m/s  V 161 m/s

32. NM03 Configurations and Sequence Timeline 1 Stack is +V3 sun pointing unless it needs to do something else (alpha angle from sunline for shading HST +V3 worksite). 2 May use a bag or box for sun shade on each item of equipment being translated (in addition to deployment of a worksite sun shade), rather than have robots carry parasols. 3 Constrain DSM SA envelope to stay out of EVA corridor, including crew, tools, instruments trajectories; DSM SA is not shaded by COTS SA, does not shade HST SA, may incidentally shade some HST worksites. 4 From moment prior to COTS capture through robot berthing to CBM/LIDS, both DSM/HST and COTS are in free drift. 5 Comm mode H indicates high-rate mode, including video data; this mode is nearly continuous since robotic activity proceeds almost constantly. 6 2 months DSM launch through deorbit, not fully scheduled, hiatuses, wait states, background ops TBD

33. Mission Timeline Robot Cleanup & Re-boost DSM Leaves DSM De-orbits COTS Leaves 2 weeks On-orbit checkout DSM RNDV w/ HST Robot Service/ Adv Prep 2 weeks Launch DSM COTS RNDV w/ DSM/ HST Airlock Pressure & C/O Service Prep HST FT Robot Cleanup & Prep EVA 2 Cont EVA EVA 1 4 days HST FT Robot Cleanup & Prep

34. DSM Mechanical – Composite/Al honeycomb panel construction, deployable payload bay doors Thermal – 15.5 m 2 radiator with embedded heat pipes, loop heat pipes for both payloads and bus components, thermostatically controlled heaters, MLI, coatings Comm –Ku band HGA to TDRS, S band omni to ground, UHF to COTS vehicle, S band to HST, GPS for orbit det. Avionics – three main flight computers, Auto FDIR and Voting ACS – Thruster-based 6-DOF control, solar inertial attitude, star trackers, IMUs, CSS Propulsion – Biprop/Monoprop pressure-regulated, 4350 kg total propellant load for 328 m/s DV, thrusters canted 60 o from sensitive areas EPS – 110 m 2 TjGaAs SA, block redundant; 8 x 100 Ah LiIon batteries; block redundant buses Solar Array size 110.23 M 2 Airlock – 170 ft 3,interior vol with exterior hatch and COTS/CBM ECLSS consumables/storage/dis tribution – N2/O2/H2O for Airlock Multi-Function Ports (12) – provide structural/power/data I/F to robot arms and other payloads e.g. sunshield Robot Arm Systems (14 m, 7 m), control electronics AR&C – LIDAR/LRF/cameras for rendezvous and capture of HST LIDS – active version docking I/F to HST CBM/LIDS – berthing I/F to COTS vehicle Sunshades (3) – approx. 1m x 3m for worksite shading EVA Payloads 3 types of SI: Axial (2), Radial, FGS (2) Small ORUs (4) CATs boxes (2) Payloads provided to S/C S/C Bus Subsystems

35. Ground System Functional Architecture DSM Mission Ops Center Mission planning & scheduling Orbit determination/control Network & contact scheduling Commanding S/C monitor/control RT health/safety processing Trending/Analysis Instrument data handling Level 0 product processing Level 0 Data Archive DSM Mission Ops Center Mission planning & scheduling Orbit determination/control Network & contact scheduling Commanding S/C monitor/control RT health/safety processing Trending/Analysis Instrument data handling Level 0 product processing Level 0 Data Archive S-band TLM: 4 kbps CMD: 2 kbps Ku-band TLM: 50 Mbps CMD: 2 kbps White Sands Complex Prime NEN Contingency CMD TLM, HK HST Control Center COTS Control Center TLM, HK CMD TLM, HK COTS Network Voice Legend: CMD = Commanding HK = House-Keeping data TLM = Telemetry data

36. Mass Rackup (1 of 2)