Close Satellites Disposal Operations: Improving Safety and Operational Efficiency

The ESSAIM family was a cluster of four microsatellites flying together in a close geometric formation. They were decommissioned at the end of 2010. CNES already had a strong experience with disposal operations for GEO and LEO satellites, but it was the first time that four close satellites had to be deorbited at the same time. Indeed, large manoeuvres performed on close satellites after many years in orbit can be risky. In addition, as a microsatellites program with limited budget, operation costs also had to be minimized. A specific and efficient manoeuvre strategy was set up, with few manoeuvres for simplicity and a particular attention to eccentricity management for safety that allowed to avoid collision risks between the ESSAIM satellite during disposal operations and over a long term, even in manoeuvre degraded case. Collision risks with other operational satellites on the way were also considered and handled during operations.