Bipropellant Enabled Solid Oxide Fuel Cell Stack Power Supply: Energy Agility for Space Vehicles

Abstract

A Solid Oxide Fuel Cell (SOFC) system capable of running on the same fuel and oxidizer as an onboard bipropellant thruster can create enhanced operational flexibility. If a spacecraft needs thrust, the bipropellant can be ignited to provide thrust. If a spacecraft needs electric power, the spacecraft can consume bipropellant to generate auxiliary power. In this work, the proven bipropellant pair ammonia (NH3) and nitrous oxide (N2O) are shown to be a viable fuel and oxidant for SOFCs, as in situ thermal NH3 cracking will generate H2 and N2O decomposition will generate O2. A 5 cell SOFC stack produced 89 W when fueled with NH3 and N2O. The results of this study demonstrate the potential for a bifunctional spacecraft system that can satisfy both operational power and on-orbit maneuverability requirements.