Molecular Propellant Hall Effect Thruster for Enabling Multi-Mode Missions

Earth Observant Inc.’s (EOI’s) Direct to Phase II work will further the development of their HET-X Hall Effect Thruster (HET) by incorporating the DoD’s desire for the use of molecular propellants in Electric Propulsion (EP) to enable multi-mode missions and to increase space asset resiliency. HETs operating directly on molecular propellants is rather novel, with little published information on compatibility or practical performance metrics. The HET-X incorporates design features not found on any other commercial HET: innovative pre-ionization technology, advanced thermal design, and a new electrical layout. These features help enable the successful testing and operation on molecular propellants. EOI intends to evaluate the HET-X against aspects of the SMC S-016 qualification process to drive design changes to enhance reliability of the hardware and provide a viable path forward for qualifying towards flight readiness. EOI will use Ascent, AF-M315E, as its main molecular propellant to conduct direct thrust measurements on the HET-X. Two key supporting subsystems to the HET-X thruster will be adapted and built so that EOI can demonstrate a path to flight to the Air Force (AF) of a HET propulsion system capable of running molecular propellants. The first subsystem would be the design and construction of a Power Processing Unit (PPU) for powering the various elements of the thruster, specifically the pre-ionizer technology and propellant flow controllers. The second subsystem would incorporate a special feed system into a more conventional Propellant Management System (PMS) for injecting molecular propellants alongside with starting and running the thruster on the control propellant of Xenon. The propulsion system that results from this work, the HET-XMP, will be a key enabling technology both commercially and for the DoD. Allowing for hybrid propulsion architectures and increased capabilities in on-orbit maneuverability.