Simulating a breakup event and propagating the orbits of space debris

Explosions or collisions of satellites around the Earth generate space debris, whose uncontrolled dynamics might raise serious threats for operational satellites. Mitigation actions can be realized on the basis of our knowledge of the characteristics of the fragments produced during the breakup event and their subsequent propagation. In this context, important information can be obtained by implementing a breakup simulator, which provides, for example, the number of fragments, their area-to-mass ratio or the relative velocity distribution as a function of the characteristic length of the fragments. Motivated by the need to analyze the dynamics of the fragments, we reconstruct a simulator based on the NASA/JSC breakup model EVOLVE 4.0 that we review for self-consistency. This model, created at the beginning of the XXI century, is based on laboratory and on-orbit tests. Given that materials and methods for building satellites are constantly progressing, we leave some key parameters variable and produce results for different choices of the parameters. We will also present an application to the Iridium–Cosmos collision and we discuss the distribution function after a breakup event. The breakup model is strongly related to the propagation of the fragments; in this work, we discuss how to choose the models and the numerical integrators, we propose examples of how fragments can disperse in time, and we study the behavior of multiple simultaneous fragmentations. Finally, we compute some indicators for detecting streams of fragments. Breakup and propagation are performed using our own simulator SIMPRO, built from EVOLVE 4.0; the executable program will be freely available on GitHub.