Joint Development of a Water Electrolysis Propelled Hall Effect Thruster and LaB6 Hollow Cathode

URA Thrusters Ltd., Aliena Pte. Ltd., and the Imperial Plasma Propulsion Laboratory (IPPL) present the development of a Hall effect thruster designed to operate on the products of water electrolysis, i.e. oxygen to the anode and hydrogen to the cathode. A pseudo-2D version of the IPPL’s particle-in-cell code PlasmaSim is used to size the discharge channel of a new thruster, termed AQUAHET. In parallel, a 0D plasma-thermal model is used by Aliena to size the emitter and orifice of a LaB6-based hollow cathode, termed Hydrocat. Preliminary test campaigns are then carried out at the IPPL and the Aliena Jet Propulsion Test Facility (JPTF). At the IPPL, a retrofitted version of an existing laboratory model thruster, the WET-HET, is tested to provide benchmarking data to validate AQUAHET channel sizing. At the JPTF, prototype and engineering model cathodes are subjected to extensive thermal and discharge characterization. After qualification and acceptance testing, the engineering model Hydrocat is shipped to the IPPL for the project’s final joint validation test campaign. The campaign began with operation of the Hydrocat alongside the retrofitted WET-HET. This marked the first time a HET had been successfully operated with the by-products of water electrolysis from pressurized bottles. Detailed characterization of the AQUAHET and Hydrocat followed. Best oxygen-hydrogen performance is obtained at 1168 ± 1 W for 1.7 mg/s of oxygen and 0.2 mg/s of hydrogen, with 19.9 ± 0.8 mN of thrust, 1217 ± 48 s of specific impulse, and 10.2 ± 0.8 % of anode thrust efficiency measured.