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A novel propellant storage system for air-breathing electric propulsion



Prime contractor
Organisational Unit
01 December 2023

Duration: 36 months


Air Breathing Electric Propulsion (ABEP) could enable use of very low Earth orbits, providing improved space services on Earth. ABEP technologies are already being developed: systems typically have an intake to collect atmospheric gas, compress it, and deliver it to an ion engine. This tight coupling of intake and engine imposes strict constraints and limits operation to a narrow band of altitudes. Our concept adds propellant storage to decouple intake and engine, which opens up a much wider range of applications. Initial work, using proven technology, shows promising results and in this study, we aim to validate the concept experimentally, as a precursor to flight demonstration.

Our storage concept uses space-proven cryocoolers to capture and store gas from the intake on a cold surface, a process known as cryopumping. Once frozen, the chamber containing the solidified gas is sealed. By raising the temperature of the pump surface, the gas can be fed to the engine when needed, and at the correct pressure to maintain ionisation. This significantly improves system performance: the capture process is more efficient and thrust can be used more effectively around the orbit. Propellant can be collected at low altitudes and used in higher ones, enabling many new mission possibilities.

In a recent feasibility study, we investigated several system designs. Results showed real promise and no showstoppers were found. For the next step we plan to prototype the critical storage technology – adopting a fail-fast approach to challenge key assumptions and simulation results. If this is successful, flight demonstration would next be possible by integrating our storage technology into existing ABEP systems.

Contract number
OSIP Idea Id
Related OSIP Campaign
Open Channel
Main application area
Generic for multiple space applications
A novel propellant storage system for air-breathing electric propulsion