Risk mitigation activities for potential collision avoidance events for cosmo-skymed constellation in flight operations

COSMO-SkyMed (COnstellation of Satellites for Mediterranean basin Observation) is an Earth Observation space program funded by the Italian Ministry of Research and Ministry of Defence (It-MoD) and managed by the Italian Space Agency (ASI) in conjunction with Italian MoD. COSMO-SkyMed (CSK) consists of a constellation of four Low Earth Orbit mid-sized satellites, each carrying a multi-mode, high resolution, electronically steerable Synthetic Aperture Radar (SAR) instrument operating at X- band and a full featured Ground Segment to properly exploit space capabilities. CSK System is fully qualified and now in operative phase, see Ref-17. The aim of this paper is to describe the characteristics and functionalities of COSMO-SkyMed collision avoidance system, highlighting its versatility and effectiveness for constellation in flight operations. Moreover, it outlines the operational activities performed at ground segment level in order to mitigate the risk arising from potential collision avoidance events. Finally, it includes the description of some real cases of management of collision avoidance events, occurred during several years of satellites in flight operations. This work has been carried out under an ASI contract. Copyright © (2012) by the International Astronautical Federation.