Title: Methane and oxygen from energy-efficient, low temperature in situ resource utilization enables missions to Mars

Abstract: NASA mandate is a human mission to Mars in the 2030s and sustained exploration of Mars requires in-situ resource utilization (ISRU). Exploiting the Martian water cycle (alongside perchlorate salts that depress the freezing point of water to less than 213K) and the available 95 volume percent atmospheric CO2, we detail an ultra-low temperature (255K) CO2-H2O electrolyzer to produce methane fuel and life-supporting oxygen on Mars. Methane production is thermodynamically favored across a range of operational pressures and temperatures and our electrolyzer polarization model concurred with reported experimental performance. A hypothetical 10-cell, 100 square cm electrode-area-per-cell electrolyzer produced 0.31g per W per day of CH4 and 3.54g per W per day of O2 at 2V per cell (operating voltage) versus 0.8g per W per day of O2 produced by the Mars Oxygen in-situ Resource Utilization Experiment (MOXIE) from the Mars 2020 mission (MOXIE produces no fuel). Material performance requirements are presented to show that this technology is an energy-efficient complement to the MOXIE high temperature approach.