Water Electrolysis for ISRU Kristopher A Lee 1

Water Electrolysis for ISRU Kristopher A. Lee 1

Why Water Electrolysis? Electrolysis is a straightforward way to make oxygen on Mars or the Moon if you can obtain water. 2

Why Water Electrolysis? Water is a common commodity in the ISRU processing of resources on Mars and the Moon Sabatier: CO + 4 H CH +2 H O 2 2 RWGS: CO 2 + H 2 4 2 CO + H 2 O Ice and hydrated minerals Hydrogen reduction: H 2 + regolith H 2 O Carbothermal reduction: CH 4 + regolith + methanation H 2 O 3

HESTIA ISRU Plant 4

Previous ISRU Water Electrolyzer 5

Current ISRU Water Electrolyzer 6

Current ISRU Water Electrolyzer Manufacturer: Number of cells: Max Pressure: O 2 per stack: Number of stacks: Giner 24 400 psi 200 g hr 2 2 Giner stacks installed in current ISRU water electrolysis system 7

HESTIA Electrolyzer Operations Integrated with the JSC Life Support group’s 20 -ft chamber at Building 7 for HESTIA Testing. Supplied 1. 86 SLPM oxygen to he chamber during 5 day HESTIA test in Sep 2015. HESTIA testing in Building 7 with 20 -foot chamber. 8

HESTIA Electrolyzer Operations Water Management Automatic internal water transfer Manual external 9

HESTIA Electrolyzer Operations Continuous, configurable fault monitoring that triggers automatic safing for dangerous conditions. Electrolyzer GUI showing parameter monitoring and configuration. 10

HESTIA Electrolyzer Lessons Learned Good system performance – Nominal O 2 production for duration of 5 -day test Water ingestion in O 2 stream – Flowing O 2 out of O 2/H 2 O separator brought liquid too Hydrogen traces in O 2 stream – Dissolved H 2 in H 2 O pumped to O 2 side 11

HESTIA Electrolyzer Lessons Learned Current ISRU electrolyzer designed primarily for in situ propellant production. Future electrolyzer should be designed with entire system in mind (including ECLSS). 12

ISS US Regenerative ECLSS from ICES-2105 -115 https: //io. jsc. nasa. gov/app/info. cfm? pid=22 224188 13

Future of ISRU Water Electrolysis Stack R&D is continuing in both ISRU and ECLSS areas Future ISRU electrolyzer should be designed with both ISRU and ECLSS in mind A System Solution!! 14

Questions? 15