Performance Characterization of the HYDROS™ Water Electrolysis Thruster

The HYDROS thruster uses a novel hybrid electrical/chemical propulsion scheme to enable CubeSates and other secondary payloads to perform missions requiring orbit agility and large ∆Vs while launching with an inert, unpressurized, non-toxic propellant: water. The HYDROS thruster splits the water propellant on-orbit using electrical power to produce hydrogen and oxygen gas. The evolved gases are then combusted in a bipropellant thruster to provide hight-thrust propulsion or utilized as cold gas to provide minimum impulse-bit thrust events. The addition of a larger gas volume to the current engineering test unit has allowed for more robust operation of the electrolyzer and longer thrust events. The parallel development of a torsional spring thrust stand allows for increased thrust and impulse measurement accuracy. Utilizing these tools we have conducted a detailed characterization of the electrolyzer and thruster performance. The electrolyzer characterization effort has demonstrated that the electrolyzer provides consistent and efficient performance across the range of upstream and downstream pressures and has demonstrated that electrolyzer wetting is the key predictor of electrolyzer performance. The thruster characterization effort has demonstrated high thrust (300-600 mN) performance and provided insight into potential design improvements moving forward