Numerical simulation of COSMOS 2499 fragmentation

In-space satellites fragmentation events contribute to the continuous growth of man-made debris. Observations of these events can provide limited information on the number and characteristics of the generated fragments, as only the largest ones can be detected with ground instrumentation. Numerical simulations replicating in-orbit fragmentation can integrate the missing information regarding fragments number, shape, and orbital distribution. In this context, this paper presents the numerical reconstruction of COSMOS 2499 break-up of January 4th, 2023. First, a digital twin of the satellite is modeled with the Collision Simulation Tool Solver, a custom semi-empirical simulation code, to replicate the explosion of an internal tank; different expansion velocities for the exploding elements are examined and the resulting fragments size and shape distributions are presented. In a second part, the effect of the attitude at the moment of the break-up on the generated debris orbital distribution is discussed. Finally, the numerical results are compared with the available data from ground observations, showing a good accordance with them.