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 - Space Debris Impact Risk Assessment Tool), 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 May 1, 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.