Speaker
Description
Very Low Earth Orbit (VLEO), orbits below 450 km, offers significant advantages for high-resolution Earth observation and low-latency telecommunications. Still, atmospheric drag poses major challenges for long-term sustainability and debris mitigation. In clean space initiatives, achieving sustainable, ecological satellite operations is a primary objective. Air-Breathing Electric Propulsion (ABEP) is a key enabling technology for extended operations; however, conventional ABEP systems remain limited by the direct coupling between thruster performance and stochastic atmospheric density. Because most ABEP concepts utilise atmospheric gases immediately, they are limited to simple drag compensation, leaving them vulnerable to density fluctuations and limiting their ability to execute critical collision-avoidance manoeuvres.
To address this limitation, this research evaluates a propellant collection and storage architecture that decouples gas harvesting from thruster operation. Building on foundational storage concepts, the architecture utilises a cryopump engineered to capture the multispecies atmospheric constituents via a multi-stage thermodynamic batch cycle. The cryopump actively captures rarefied gases during cooling and subsequently serves as a high-pressure regeneration vessel during heating, transferring dense propellant into a central storage tank.
This on-demand propellant supply ensures fuel for agile, high-thrust manoeuvres and mission continuity during atmospheric deficits that would otherwise cause failure in traditional ABEP systems. This research will detail a numerical framework developed in MATLAB that employs the NRLMSIS 2.1 atmospheric model, incorporating altitude-dependent densities and variable drag coefficients to evaluate the system's operational envelope. By simulating these parameters across varying solar activity levels, the system's operational envelope, minimum survival altitudes, peak daily propellant yields, and necessary refill timelines are defined.
The results validate that an ABEP system can collect more propellant than is needed for direct drag compensation. By storing this excess, the architecture breaks the limitations of immediate use harvesting and introduces sustainable, propellant-less operations. Specifically, it would enable novel mission architectures in which satellites in higher orbits can periodically lower their perigee to VLEO to refuel from the atmosphere before returning to their operational altitude. This technology not only enhances spacecraft robustness for collision avoidance and zero-debris compliance but also establishes a foundation for ecological in-space operations independent of Earth-launched propellants.