Assessment of breakup severity on operational satellites

In the past years, several methods have been proposed to rank spacecraft and space debris objects depending on their effect on the space environment. The interest in this kind of indices is primarily motivated by the need of prioritising potential candidates of active debris removal missions and to decide on the required reliability for disposal actions during the design phase. The index proposed in this work measures the effect of the catastrophic fragmentation of the analysed spacecraft in terms of the resulting collision probability for operational spacecraft. The propagation of the debris cloud generated by the fragmentation and the estimation of the collision probability are obtained by applying an analytical approach based on the study of the density of the fragment cloud. The dependence of the proposed severity index on the mass of the spacecraft and on its semi-major axis and inclination is investigated. The index was computed for the objects in the DISCOS database and its results were compared to other formulations proposed in literature. A discussion on the results and on the comparison is presented.