In a first for Galileo, a satellite performed a collision-avoidance maneuver to avoid space debris.
Under the management of the European GNSS Agency (GSA), the maneuver for satellite GSAT0219 was performed March 6 following a collision risk alert received from EU Space Surveillance and Tracking (EUSST).
Event timeline. (Image: EUSST)
On Feb. 25, the Galileo Service Operator (GSOp) received from EUSST a collision risk alert between GSAT0219 and an inert Ariane 4 upper stage launched in 1989. Following the warning, GSOp closely monitored the risk, in close cooperation with EUSST that was refining its predictions.
In line with operational procedures, GSOp informed the GSA of the situation. In a joint effort with the European Commission, the GSA managed the follow-up activities. The effective cooperation between EUSST and the GSA/GSOp was instrumental to the success of the mission and bears testimony to the need for efficient cooperation between different organizations in the space sector.
Maneuver Authorized
Following refinement of the Ariane 4 orbit, the risk of collision was still unacceptably high. After assessment of different strategies and associated risks on the service provision, the GSA authorized the execution of an avoidance maneuver.
The satellite was taken out of service on March 5, and users were informed via NAGU #2021009. The collision avoidance maneuver was performed shortly thereafter, by temporarily relocating the satellite away from its nominal position.
Satellite GSAT0219 was reintroduced into service on March 19 after the completion of two station-keeping maneuvers to reposition it into its nominal operational orbit. A second NAGU advised users that the satellite was once again available.
Map of sensors contributing to the event. (Image: EUSST)