Air-Breathing Electric Propulsion with Oxygen Resilience for Long Duration Operation in VLEO

The Air-Breathing Electric Propulsion (ABEP) system enables long-duration, fuel-independent operations in Very Low Earth Orbit (VLEO), supporting the Department of Defense’s (DoD) need for sustained space maneuverability and resilience in contested environments. ABEP eliminates reliance on stored propellants by collecting and processing atmospheric gases to power a Hall Effect Thruster (HET), significantly extending mission lifetimes and reducing operational costs. This Phase II effort focuses on advancing ABEP’s core enabling technology: an oxygen-resistant cathode system utilizing RF Cathode Technology and an Oxygen Transport Membrane (OTM) filter. Current electric propulsion systems struggle with cathode degradation in oxygen-rich environments, limiting their viability in VLEO. Traditional thermionic cathodes degrade when exposed to atomic oxygen.  RF cathodes can serve to minimize materials that are particularly susceptible to oxygen, but to fully overcome these challenges, Viridian Space has partnered with Northrop Grumman to integrate an OTM filter, selectively removing oxygen from the cathode feed, enabling stable long-term operation in VLEO’s atmospheric composition. This effort builds upon a successful Phase I feasibility study, which identified RF Cathodes and OTM-filter technology as the optimal solution for sustaining ABEP operations. Phase II objectives include designing, fabricating, and validating the OTM-filtered RF cathode in a simulated VLEO environment, developing an optimized flow control system, and integrating the cathode with an ABEP testbed. The anticipated results will advance the system’s Technology Readiness Level (TRL) from 3-4 to 5-6, demonstrating key performance parameters required for a future flight demonstration in Phase III. The outcome of this effort will provide DoD with a revolutionary propulsion system for maneuverable, fuel-independent spacecraft, supporting ISR, tactical mobility, and resilient space logistics in VLEO.