First collision avoidance manoeuvre

First collision avoidance manoeuvre
22.03.2021 spaceopal-GmbH

First collision avoidance manoeuvre for a Galileo satellite has been successfully implemented

Under the leadership of the European GNSS Agency (GSA), Spaceopal managed the first time a sequence of collision avoidance manoeuvres for a Galileo satellite. It has been an orchestrated work with the two centres, GCC-D for the aspects related to the satellite control and GCC-I for the mission impacts management. These manoeuvres were conducted following a collision risk alert received from EU Space Surveillance and Tracking (EUSST).

On 25 February, Spaceopal, the Galileo Service Operator (GSOp), received from the EUSST a collision risk alert between a Galileo satellite (GSAT0219) and the debris of an inert Ariane 4 upper stage launched in 1989. Following this warning, Spaceopal together with the operations teams on site started to closely monitor the risk, in close cooperation with EUSST that was refining its predictions.

In line with operational procedures, Spaceopal informed the GSA of the situation. In a joint effort together with the European Commission and the GSA all the follow-up activities have been professionally managed. The effective cooperation between stakeholders was instrumental to the success of the mission and bears testimony to the need for efficient cooperation between different organisations in the space sector.

Following refinement of the Ariane 4 orbit, the risk of collision was still unacceptably high, so, after assessment of different strategies and associated risks on the service provision, the GSA authorised the execution of an avoidance manoeuvre.

The satellite was taken out of service on 5 March, and users were informed via NAGU #2021009. The collision avoidance manoeuvre was performed shortly thereafter, by temporarily relocating the satellite away from its nominal position. All this has been perfectly managed.

The satellite has been reintroduced into service after the completion of two station keeping manoeuvres to reposition it into its nominal operational orbit and after completion of mission task service related optimized to minimize the overall satellite time unavailability. Users have always be kept informed via NAGUs.

The implementation of the first time collision avoidance manoeuvre affecting the Galileo constellation was another excellent proof of cooperation between the industrial team servicing the Galileo System, responsible for ensuring the service continuity of the Galileo System and the institutional sector.