Protecting space environment

Sustainability in and from space is a core priority for ESA, that promotes a responsible use of space to benefit both society and the environment. Central to this commitment is reducing space debris, a serious global hazard threatening current and future missions, and the essential services they provide.

To address the growing space debris issue, ESA has set an ambitious goal of net zero space pollution for new missions by 2030. This target is backed by sustainable design practices, rigorous debris mitigation policies and end-of-life satellite disposal protocols.

ESA, as system development prime and design authority for Galileo, has aligned Galileo’s space segment management with the agency's Space Debris Mitigation Policy and Requirements, showing dedication to sustainable space activities and setting an example as a key European flagship programme. Galileo satellite decommissioning operations are coordinated by EUSPA.

When a Galileo satellite reaches end of service, it is to be moved to a higher and safe orbit and passivated by depleting all its sources of energy. Galileo’s graveyard orbits are located at least 300 km above the active constellation and are designed to remain stable for a very long time. This is a vast region that does not interfere with Galileo, geostationary satellites or any other constellation for hundreds of years.

Thanks to the propellant reserves in GSAT0104, it was possible to place it 700 km above the Galileo operational constellation on a very stable disposal orbit. Then, the satellite tank was depleted and the satellite passivated by removing all internal energy, such as battery charge. Future decommissioned Galileo satellites will be disposed at slightly different altitudes to maintain a safe distance between them.

Graveyard orbits are the standard disposal strategy for satellites in medium Earth and geostationary orbits, where Earth re-entry is generally not feasible.