Water Electrolysis Technologies for Extraterrestrial Water Resource Conversion

ABSTRACT Extraterrestrial water resources are critical strategic assets for the establishment of off‐earth bases and long‐term deep space exploration. Based on a systematic review of water resource types and characteristics in space stations and lunar and Martian environments, this paper focuses on four water electrolysis technologies for extraterrestrial water conversion: alkaline water electrolysis, proton exchange membrane water electrolysis, solid oxide water electrolysis, and anion exchange membrane water electrolysis. It elaborates on their reaction mechanisms, core components, and system integration approaches. Drawing from engineering practices of water electrolysis systems in space stations, the analysis highlights unique challenges posed by extraterrestrial environments, including key technical bottlenecks such as complex water purification, bubble detachment, gas–liquid two‐phase flow control of the electrolyzer, gas–liquid separation, and system environmental adaptability. Furthermore, discussions are provided on the prospects for large‐scale water electrolysis, high‐pressure water electrolysis, and direct electrolysis of unpurified water, which serve as technical references for the future in situ utilization of lunar, Martian, and other extraterrestrial water resources.