Abstract:
Knowing the likelihood of collision for satellites operating in Geosynchronous Earth Orbit (GEO) is of extreme
importance and interest to the global community and the operators of GEO spacecraft. Yet for all of its importance, a
comprehensive assessment of GEO collision likelihood is difficult to do and has never been done. In this paper, we
employ six independent and diverse assessment methods to estimate GEO collision likelihood. Taken in aggregate,
this comprehensive assessment offer new insights into GEO collision likelihood that are within a factor of 3.5 of each
other. These results are then compared to four collision and seven encounter rate estimates previously published.
Collectively, these new findings indicate that collision likelihood in GEO is as much as four orders of magnitude higher
than previously published by other researchers. Results indicate that a collision is likely to occur every 4 years for one
satellite out of the entire GEO active satellite population against a 1 cm RSO catalogue, and every 50 years against a
20 cm RSO catalogue. Further, previous assertions that collision relative velocities are low (i.e., < 1 km/s) in GEO are
disproven, with some GEO relative velocities as high as 4 km/s identified. These new findings indicate that unless
operators successfully mitigate this collision risk, the GEO orbital arc is and will remain at high risk of collision, with
the potential for serious follow-on collision threats from post-collision debris when a substantial GEO collision occurs.
Keywords: GEO collision likelihood, encounter rate, comprehensive, collision risk.
Oltrogge, D.L., Alfano, S., Law, C., Cacioni, A. and Kelso, T.S., “A Comprehensive Assessment of Collision Likelihood in Geosynchronous Earth Orbit,” IAC-17,A6,2,4,x39125, 2017 International Astronautical Congress, Adelaide, Australia, 26 September 2017, accessible at https://comspoc.com/Resources/Content/Private/C-20220422T150555/Paper/IAC-17,A6,2,4,x39125.pdf
