Collision Risk Monitoring for SPOT Satellites


F. Alby (2000), JBIS53, 39-44

Refcode: 2000.53.39

After the loss of SPOT 3 CNES decided to study more in detail the collision risk between the SPOT satellites and the catalogued space debris. The main objectives of this experimental procedure were to better assess the risk and to highlight the technical and operational difficulties of such monitoring. For that purpose a dedicated procedure was implemented in the Operational Orbit Centre: this procedure makes use of software already developed in the framework of previous R&D studies and takes as input two-line element sets and external radar tracking data. The procedure was used for one year, in a near operational context, to predict the collision risk between the 3 SPOT satellites and the objects in space. In particular this monitoring evidenced in real time some very critical cases which are detailed: for instance, one of these cases led to performing an avoidance manoeuvre. In addition, after a one-year experiment, a preliminary assessment could be carried out, giving in particular statistical information concerning the fly-by distances between the satellites and the objects in space. Finally the need for new theoretical studies was evidenced together with software developments in view of a possible future system.