ESA decommissions the first Galileo satellite

On March 12, 2013, the time had come: with GSAT0104, four Galileo satellites were operational in orbit, making it possible to determine their position using the European satellite navigation system. According to the European Space Agency (ESA), it was the first satellite in the constellation to be decommissioned.

GSAT0104 is one of the 38 Galileo satellites of the first generation. These were designed to operate for twelve years, which is why GSAT0104 has now been decommissioned, the ESA announced. This has no impact on the functionality of Galileo.

GSAT0104 was launched on October 12, 2012 from the Kourou launch site in the French overseas department of French Guiana. On board the Russian Soyuz-ST-B launch vehicle was another in-orbit validation (IOV) satellite. The first two IOV satellites were launched into space in October 2011.

Decommissioning was decided in October 2023, work began in March 2024 and was completed in April of this year, according to ESA. To ensure that a decommissioned Galileo does not pose a risk to other satellites, it is transferred to a so-called graveyard orbit at the end of its mission. These orbits are located at least 300 kilometers above the active constellation and are designed to remain stable over a very long period of time.

Because GSAT0104 still had enough fuel reserves, it could even be placed 700 kilometers above the operational Galileo constellation, according to ESA. The tank was then emptied and the satellite was finally deactivated. The satellites that will be decommissioned in the future will each be placed at a slightly different altitude to avoid collisions.

"At Galileo, we need to keep the orbits clear and safe to enable the continuous renewal of the fleet," said Riccardo Di Corato, Head of the Galileo Constellation Analysis Unit. "It is crucial that a satellite is removed from the constellation while key components such as attitude control, thrusters and telecommunication systems are still functioning. If we are certain that the satellite can be disposed of at a later date, we will extend its operation for as long as possible." This is the case with the three remaining IOV satellites: they are not due to be decommissioned until the end of this year.

(wpl)