1. National Aeronautics and Space Administration Asteroid Redirect Mission Solar Electric Propulsion 18 May 2016 Michael J. Barrett NASA-Glenn Space Technology Project Office

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3. Solar Electric Propulsion Flight Evolution 1998 Deep Space-1: 2 kW NASA Tech demo, asteroid comet flyby 2003 Hayabusa: 2 kW JAXA Tech demo, asteroid sample/return 2008 SMART-1: 1.5kW ESA Tech demo, lunar science 2010-2011 Advanced EHF: 15kW DoD comsat 6.2mT S/C with 3mT of biprop propellant Launched to GTO, apogee engine failure, 9kW EP system used for GEO transfer Over the course of a year ~ 500 maneuvers (from mins to >14 hrs) to reach GEO SEP saved $1.6 B asset with full function 1990’s – present: Geostationary Communication Satellites: kW-class solar electric propulsion used for station keeping by all foreign and domestic satellite manufacturers Using SEP increased operational lifetimes up to 18 years Substantially increased payload capability 100’s of spacecraft and tens of thousands hours of successful on- orbit operation 1 kW 10 kW 500 kW 2030s: 200 - 500 kW Possibilities Human missions to Mars Hybrid Chem/SEP vehicle for crew SEP vehicle for prepositioning assets 2020-2025: 50 kW Possibilities HEOMD – Asteroid Redirect Robotic Mission SMD – Mars Orbiter & sample return DoD – space situational awareness Commercial – geo insertion & orbital servicing 2025-2030: 80 - 200 kW Possibilities Proving Ground Logistics resupply Excursion mission capability 50 kW 2007-2016 Dawn: 2 kW (10 kW @ 1AU) NASA SMD mission, asteroid rendezvous 100 kW

4. 4 Asteroid Redirect Mission: Three Main Segments Infrared Telescope Facility GoldstoneArecibo NEOWISE IDENTIFY REDIRECT EXPLORE Ground and space based assets detect and characterize potential target asteroids Solar electric propulsion (SEP) based system redirects asteroid to cis- lunar space. Crew launches aboard SLS rocket, travels to redirected asteroid in Orion spacecraft to rendezvous with redirected asteroid, studies and returns samples to Earth Pan-STARRS 4

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6. 6 Robotic mission acquisition strategy decisionsAug 2015 Formulation Assessment and Support Team (FAST) establishedAug 2015 Robotic mission requirements technical interchange meeting Dec 2015 Update with Small Bodies Assessment GroupJan 2016 Robotic spacecraft early design study contracts selectedJan 2016 Formulation guidance updated for ARRM KDP-BFeb 2016 Crewed segment operational requirements meetingsFeb 2016 FAST final report releasedFeb 2016 STMD electric propulsion development contract selectionApr 2016 Asteroid Redirect Mission Progress

7. SEP System Extensibility for Notional Vehicles 7 Proving Grounds or Split Mars Architecture Hybrid Mars Architecture 50-kW Solar Array System 40-kW EP System 5-t class Xenon Capacity - Refueling Capability 13-kW EP strings 190-kW Solar Array 150-kW EP System 16-t class Xenon Capacity 13-kW EP strings 400-kW class Solar Array 300-kW class EP System 16-t class Xenon Capacity 30-kW class EP strings or 13-kW strings Initial SEP Bus Note: Complexity of using multiple EP strings is more like managing multiple electrical loads than employing multiple chemical engines.

8. Notional SEP Bus for ARM Operations 104

9. Major Risk-reduction Activities Completed Solar Array Development Contracts Fully Successful  MegaFlex Engineering Development Unit  ROSA Engineering Development Unit  Both arrays achieved all SOA-related goals including:  4x rad tolerance  1.7x power/mass (kW/kg)  4x stowed volume efficiency  20x deployed strength Technology Development Thruster and PPU Tests at NASA-Glenn  Confirmed thruster magnetic shielding (enables long-life operation)  Power Processing Unit vacuum tests successfully completed  Conducted 12.5 kW thruster integrated tests with 300-V and 120-V PPUs  400+ hours of testing completed 9 Demonstrated full performance compatibility between thruster and PPUs

10. Advanced Electric Propulsion System (AEPS) Contract NNC15ZCH014R (Base: EDU hardware; Opt: Flight hardware) 10 Contract award announced April 2016 If option executed, flight hardware delivery anticipated in CY19 (1 qual, 4 flight) 6-13kW class string; 200-700mN class thrust (throttleable)

11. Next Strategic Technology Exploration Partnership (NextSTEP) Broad Area Announcement (BAA) selected 3 propulsion systems for development –Ad Astra: VASIMR (Variable Specific Impulse Magnetoplasma Rocket) –MSNW: ELF-250 (Electrodeless Lorentz Force) –Aerojet-Rocketdyne: Nested Hall Thruster All Contracts awarded –1-yr. base development contracts w/two 1 yr. options –All Demos to be completed by late FY18 or early FY 19 Primary goal: during third year demonstrate 100 hours continuous, steady-state, 100-kW operation of propulsion system in a relevant environment –System includes thruster, power processing unit, feed system, and other key subsystems Key performance goals include Isp range of 2,000 to 5,000s, total system efficiency> 60%, operational life> 10,000 hrs, total system specific mass < 5kg/kw, and scalable to MW levels Alternate Electric Propulsion Options: NextSTEP BAA 14

12. 12 Notional Solar Electric Propulsion Development Blocks Mars Hybrid Xport (300kW EP) ProvingGround  2 and Mars Cargo Xport (150kW EP) ProvingGround  1 (40kW EP) kW AEPS 13kW HERMeS' 30-50kW (PPU or DDU as options) Demonstrate large scale solar electric propulsion capability, performance Validate higher power generation and electric propulsion system capability in deep space HERMeS’ 30-50kW Annular Ion 20-60kW Nested Hall 100kW VASIMR 100kW ELF 100kW AEPS 13kW Annular Ion 20-60kW Nested Hall 100kW VASIMR 100kW ELF 100kW Bold Green Text : Reference Plain Green Text: ARRM-derived option Yellow Text: Other alternate SEP  SEP  ARRM BUS SEP  Images not to scale

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15. 15 Supplemental Material

16. 16 Orbiter MPS Helium System Complexity

17. ARM: An Early Mission in the Proving Ground of Cis-Lunar Space 17 TRANSPORTATION & OPERATIONS: Capture and control of non- cooperative objects Common rendezvous sensors and docking systems for deep space Cis-lunar operations are proving ground for deep space operations, trajectory, and navigation TRANSPORTATION & OPERATIONS: Capture and control of non- cooperative objects Common rendezvous sensors and docking systems for deep space Cis-lunar operations are proving ground for deep space operations, trajectory, and navigation IN-SPACE POWER & PROPULSION: High efficiency 40kW SEP extensible to Mars cargo missions Power enhancements feed forward to deep-space habitats and transit vehicles IN-SPACE POWER & PROPULSION: High efficiency 40kW SEP extensible to Mars cargo missions Power enhancements feed forward to deep-space habitats and transit vehicles High Efficiency Large Solar Arrays Exploration EVA Capabilities Solar Electric Propulsion EXTRAVEHICULAR ACTIVITIES: Two in-space EVAs of four hours each Primary Life Support System design accommodates Mars Sample selection, collection, containment, and return EXTRAVEHICULAR ACTIVITIES: Two in-space EVAs of four hours each Primary Life Support System design accommodates Mars Sample selection, collection, containment, and return Deep-Space Rendezvous Sensors & Docking Capabilities

18. Key Aspects of ARM 18 Moving large objects through interplanetary space using SEP Integrated crewed/robotic vehicle operations in lunar distant retrograde orbit (DRO) –Integrated attitude control, e.g. solar alignment –Multi hour EVAs Lean implementation –Clean interfaces, streamlined processes –Common rendezvous sensor procurement for robotic vehicle and Orion Integrates robotic mission and human space flight (HSF) capabilities –HSF hardware deliveries to and integration and test with robotic spacecraft –Joint robotic spacecraft and HSF mission operations

19. Split Mission Concept Returning from Mars, the crew will return to Earth in Orion and the Mars Transit Habitat will return to the staging point in cis-lunar space for refurbishment for future missions 19

20. PROVING GROUND OBJECTIVES 20 Enabling Human Missions to Mars ISRU: Understand the nature and distribution of volatiles and extraction techniques and decide on their potential use in human exploration architecture. Deep-space operations capabilities: EVA, Staging, Logistics, Human-robotic integration, Autonomous operations Science: enable science community objectives Heavy Launch Capability: beyond low-Earth orbit launch capabilities for crew, co- manifested payloads, large cargo Crew: transport at least four crew to cislunar space In-Space Propulsion: send crew and cargo on Mars-class mission durations and distances TRANSPORTATIONWORKING IN SPACESTAYING HEALTHY Deep-Space Habitation: beyond low- Earth orbit habitation systems sufficient to support at least four crew on Mars-class mission durations and dormancy Crew Health: Validate crew health, performance and mitigation protocols for Mars-class missions