Review of Techniques for In-Situ Oxygen Extraction on the Moon

Resources intrinsic to the lunar environment, the abundant and oxide rich surface regolith and local water ice reserves, can be processed in order to liberate O-2 and H-2 gases for downstream applications in life support or as propellant. The range of extraction processes continues to evolve and the technology readiness level (TRL) develops, with a perspective of having initial demonstration missions in the medium term on the lunar surface. Of these processes, renewed focus has been on a subset which show significant potential; extraction via a reactive gas, reduction via electrolysis, vapour phase pyrolysis and thermal extraction of volatiles and water ice. These processes are outlined herein, their general principles, thermodynamic fundamentals and possible reactor layouts are described and their current state of the art is presented.