The European Space Agency has announced a new initiative to design, build, and test a prototype in-orbit refuelling system for green, self-pressurizing propellants.
Announced on 6 February, the In-Orbit Test of Prototype Refuelling Technologies for Green Propellants initiative will be jointly managed by the agency’s Space Transportation and Connectivity and Secure Communications directorates. The initiative aims to extend a satellite’s in-orbit lifespan by more than 100%.
In addition to identifying satellite life extension as a benefit of this technology, the announcement highlights the potential to reduce the propellant load needed at launch by over 50%. Since propellant can account for up to 50% of a satellite’s total launch mass, any reduction here could significantly ease the demands on the launch vehicle, opening up payload capacity.
The initiative will be implemented in two phases, with the first phase focused on the design, manufacture, and flight readiness of the prototype system. The second will be the actual in-orbit demonstration mission itself, which will validate the docking interface and evaluate the propellant transfer performance.
According to the call, the initiative is focused on equipping multi-orbit satellite communication constellations with in-orbit refuelling capabilities. This is likely a direct reference to IRIS², the European Commission’s €10.6 billion secure communications constellation. That’s also why the project features the involvement of the agency’s Connectivity and Secure Communications directorate.
The planned in-orbit refuelling demonstration mission isn’t the only initiative of its kind being pursued by ESA. In October 2024, the agency announced that it had selected ArianeGroup, GMV Aerospace and Defence, MT Aerospace, SAB Aerospace, and The Exploration Company to develop in-orbit fuel storage and refilling capabilities.
Also in October 2024, ESA awarded a €119 million contract to D-Orbit for the development of the agency’s first in-orbit servicing mission, RISE. While this mission focuses on using a vehicle to extend the life of a client satellite, ESA called the initiative “a promising step towards enhancing in-orbit services and technologies.”
With ESA launching a third initiative in less than a year, it’s clear that in-orbit life extension is a priority for the agency.
