Impact risk repercussions on the iridium and COSMO-SkyMed constellations of two recent catastrophic collisions in space

Following the catastrophic collisional breakups of three intact spacecraft (Fengyun 1C, Cosmos 2251 and Iridium 33) occurred in low Earth orbit, a detailed analysis was carried out, with a dedicated software tool (SDIRAT), in order to evaluate the additional impact flux of cataloged objects on the satellites of two operational constellations in high inclination orbits, Iridium and COSMO-SkyMed. As of 1 May 2011, the flux increase with respect to the debris background was 160%, on average, for the Iridium satellites, distributed on six equally spaced orbit planes at 781 km, and 47% at the altitude of the COSMO-SkyMed constellation, using a single orbit plane at 623 km.