Ultra-cold Electrolytic In-situ Resource Utilization (ISRU) for Fuel and Oxygen Production on Mars

Provisioning a crewed Mars mission from Earth, including 35,000-40,000kg of propellant needed for the return journey, is estimated to require ~400,000kg of propellant (fuel and oxidant) on 4–5 heavy lift launch vehicles. Thus, future crewed Martian missions necessitates “living off the land” through in-situ Resource Utilization (ISRU). The National Aeronautics and Space Administration (NASA) is considering deploying an ISRU electrolyzer 26 months before a human mission to produce 25,000–30,000 kg of oxygen (O2) using atmospheric CO2 abundantly present on Mars. This solid electrolyzer was tested using the Mars Oxygen ISRU-Experiment (MOXIE) device onboard the Perseverance rover. I studied a low-temperature electrolyzer that produces rocket propellant (CH4) and life-supporting oxygen utilizing Martian brines and atmospheric CO2 to remedy the pitfalls of MOXIE. I have completed the framework for this Martian ISRU life-support brine - CO2 electrolyzer by first modelling a hypothetical 10-cell, 100 cm2 electrode-area-per-cell, 50% faradaic efficiency (FE) electrolyzer, which produced 0.45 gW 1day-1 of CH4 and 3.55 gW 1day-1 of O2 at 2V/cell vs. MOXIE’s production of 2.5 gW 1day-1 of O2. This modelling was expanded to alternative configurations for Martian ISRU brine - CO2 electrolysis to produce CO, HCHO, CH3OH, C2H4, and C2H5OH to provide the industrial backbone needed to explore the solar system. Additionally, I have shown that silver wire pseudo-reference electrodes are stable for Martian brine electrochemistry. This electrode was integral to exploring the kinetics of the primary competing hydrogen evolution reaction in ambient Martian temperatures to address the anti-Arrhenius behavior recorded by other groups. The findings herein establish this technology as a promising ISRU methodology for sustainable Martian exploration.