Self-induced collision hazard in high and moderate inclination satellite constellations

Abstract

The assessment of the hazard posed by space debris to constellations of satellites in low Earth orbit is of growing importance, with the proliferation of proposed and implemented constellation systems with a variety of mission objectives. This applies to current constellation-based commercial communication systems, in particular, since these are typically deployed at altitudes where there is a peak in the space debris environment. An impact risk analysis is performed over a period of up to 1 month after a breakup event using two examples of constellation configurations. The first is similar to the IRIDIUM system, containing around 70 satellites in near-polar orbits at approximately 800 km altitude, and the second is a Globalstar-like configuration with 56 satellites at around 1400 km altitude, distributed in orbit planes inclined at 52°. The analysis is performed using the SDS software, which applies the probabilistic continuum dynamics technique. This has the benefit of being a self-contained and rigorous method. However, it is found to be not well-suited to ‘long-term’ analysis, due to the computational effort required. The risk analysis for the chosen examples is presented, as well as an investigation of the robustness of the method when applied to complex and ‘long-period’ simulations.