Atmosphere Independent Bipropellant Solid Oxide Fuel Cells (SOFCs) for On-Orbit Space Power
Sustained duration power output onboard modern spacecraft is primarily constrained by the rate of photovoltaic energy collection or the limited energy density of batteries. An alternative energy source is mandatory during eclipse, lunar night scenarios, or short manned missions such as the Apollo program where the long duration energy consumption made batteries infeasible. As a solution, the chemical energy of the propellants onboard a spacecraft can be utilized for electrochemical work in a fuel cell, thereby taking advantage of the much higher specific energy of liquid fuels. The hypergolic pair MMH/NTO represent a specific energy density approximately eight times that of modern space-worthy lithium-ion batteries. The option to use propellants for thrust and/or power greatly reduces the invested weight in the final plumbing and storage. Regenerative fuel cells have already been studied as a prospective power sources for satellites, as well as reusable fuel cells fed with hypergolic propellants for spacecraft. A similar solid oxide electrolyzer cell has already been successfully integrated into the Mars Perseverance rover. This project seeks to validate the concept of a solid oxide fuel cell integrated with a hypergolic bipropellant propulsion system.
