CRYSALIS · Cryogenic storage and refuelling in space

To move away from the dependence on hydrazine for space propulsion, greener alternatives must be sought. Cryogenic propellant combinations such as oxygen / methane offer higher specific impulses than storable combinations, but their low saturation temperatures raise additional challenges with respect to preventing their evaporation during long-term storage. While the ability to refuel craft with cryogenic propellants would allow for longer-term manned missions to Mars and the Moon, as well as aid in the improvement of in-space sustainability, preventing the evaporation of the propellants during the transfer process also poses challenges. As of today, neither long-term storage nor refuelling with cryogenic propellants has been demonstrated in-orbit. CRYSALIS will develop and mature the technologies needed for the management of cryogenic propellant for future space transportation and in-orbit servicing activities. This maturation will include performing a small-scale in-orbit demonstration to mature those whose performance can only be characterised in a microgravity environment. This will be a closed-system demonstrator flown on-board the Nyx capsule, which will aim to not only demonstrate the feasibility of such processes but will aim to improve the understanding of the behaviour of such propellants under microgravity, allowing for development of future systems. These technologies will aid in ensuring the independent access of the EU to space, in particular to manned and heavy missions beyond GEO and LEO, by supporting the development of a logistical network of craft, depots, and hubs, required for cis-lunar and future Martian missions.