Analysis for chain-crash risk of LEO satellite due to collision between Iridium-33 and Cosmos-2251

The commercial communication satellite, Iridium-33 and a defunct Russian satellite, Cosmos-2251 ran into each other on February 10, 2009 above Northern Siberia, creating a cloud of debris. The impact occurred at 16:56:00 UTC, at latitude 72°20′04″, longitude 97°52′46″, altitude 788.68 km. As a result of these events, it is assumed that a significant amount of debris including thousands or even tens of thousands of fragments was produced. In this research, the probability of chain-crash between debris fragments generated by the collision and a Korean LEO satellite, which has been performing its mission in sun-synchronous orbit with 685 km altitude, was analyzed. The breakup model for the catastrophic collision, in which both the satellites are totally fragmented, was applied for modeling debris parameters which consist of size, mass, and delta-velocity and so on. The orbits of the fragments generated after the collision and the Korean LEO satellite were propagated in order to estimate other collision possibility between them. In especial, the orbit of each fragmentation using SGP4 propagator is propagated individually instead of the debris cloud propagation. The osculating orbits of the fragments were converted into the mean orbit of Two Line Element (TLE) using the Newton-Rhapson iterative procedure. The weekly update TLE was also used for propagation of the Korean LEO satellite. A Monte Carlo simulation was implemented to estimate statistical possibility of collisions. The result shows that the evolution of collision fragmentations increases the possibility of additional collision between the fragments and the Korean LEO satellite.