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Solid Oxide Electrolysis (SOE) with an embedded Sabatier reactor is an innovative and efficient concept for regenerative air revitalization. The concept safely eliminates handling of hydrogen, and works regardless of gravity and pressure environments with no moving parts and no multi-phase flows. It also is efficient because it requires no expendables from Earth while being compact with minimal impact on mass. The consequence is significant because SOE is an inherently suitable technology (and possibly the only technology) for enabling 100% oxygen regeneration from carbon dioxide and water vapor, two byproducts of crew activity that must be managed. To investigate the feasibility of this concept, a Sabatier reactor was successfully embedded into a single SOE cell.

Solid oxide electrolysis with embedded Sabatier reactors is being developed to regenerate all the oxygen required by a crew, eliminating any resupply needs. Metabolically produced carbon dioxide and water are electrolyzed at high temperature to produce pure dry oxygen. Carbon monoxide and hydrogen byproducts are converted to methane and water in the embedded Sabatier reactor. As it is embedded in the electrolyzer, the water is further electrolyzed to produce additional oxygen. A demonstration unit has been designed at full scale with a design production rate equivalent to that required to support one third of one person's oxygen requirements. Stack design was configured to enable the electrolyzer and Sabatier stacks to operate at their respective temperatures. Thermal modeling was performed to support internal heater sizing, insulation design, and evaluate touch temperatures. The unit was built and tested. Modeling and initial testing results are presented.

Solid Oxide Electrolysis with an embedded Sabatier reactor is being developed for regenerative air revitalization. In a previous effort, an embedded Sabatier reactor was demonstrated using a nickel-based electrode in a SOE cell. To explore the performance potential, new experiments were performed at various operating temperatures and inlet gas compositions. Successful methane and oxygen regeneration was achieved. The gas compositions fed to the cell were a mixture of carbon dioxide, water, carbon monoxide, and hydrogen in ratios indicative of a previously electrolyzed stream of metabolically produced by-products (carbon dioxide and water vapor) of nominal crew activity. The composition was varied by simulating various degrees of oxygen regeneration by upstream electrolysis cells. All results are presented and compared to previous testing where applicable. Carbon deposition was observed in the inlet tube to the cell.