Description: Supporting human life on long-tern space exploration missions to the surface of Mars requires sustainable in-situ resource utilization with minimal support from Earth. In particular, atmospheric carbon dioxide (CO2), which makes up 95% of the atmosphere on Mars, provides an abundant in-situ resource for human explorers. CO2 can be electrochemically reduced into ethanol, which exists as a liquid on the Martian surface, allowing for relative ease of storage.Ethanol is a critical component for manned missions to exoplanets, as this chemical is a high energy density fuel (30 MJ/kg), is a potent chemical for sterilization of equipment to prevent cross contamination of Earth life and potential Martian life, and can be used as a solvent for a variety of scientific experiments. Phase I demonstrated the feasibility of electrochemical conversion of atmospheric CO2 to ethanol. Ethanol was produced at a rate of 2.2 g per hour, with an energy efficiency of 0.31 g of ethanol per watt-hour and faradic efficiencies of87% and 72% for catalyst and electrochemical cell, respectively. Phase II will include improvement of the catalyzed cathode surface to achieve a faradaic efficiency in the cell of at least 80%, coupled with scaling the cell to increase the ethanol production rate to at least 20 g per hour at an energy efficiency of 0.5 g of ethanol per watt-hour. We will produce ethanol under conditions that are relevant to the surface of Mars (down to -60℃ and 7 mbar), work on purification of the ethanol product, and perform durability testing, catalyst regeneration studies, and operation under various orientations versus gravity. Phase II will include designing an alpha-scale electrochemical cell for testing in later work, with the long term goal of ethanol production rates of 2.8 kg per hour. We will reach out to commercialization partners in the space industry to align the technology transition to their needs.

Benefits: Production of high-value energy and chemical feedstocks using in-situ resources is critical for success of manned missions to Mars. The proposed technology would support lower launch masses required for escaping Earth’s gravity well and long-term activities on the Martian surface. Ethanol produced using this technology could be used as a fuel source, for disinfection, or as a feedstock for production of materials such as polyethylene. The oxygen produced as a byproduct can be used in life-support systems or an oxidant in propellants.