Estimating Encounters: An Assessment of Space Debris Collision Risk in Low-Earth Orbit From 1960 to 2015

Abstract

The total number of objects in the U.S. Strategic Command’s (USSTRATCOM) space debris catalog has greatly increased from 1960 to 2015. This paper shows that the number of near collisions per day for a specified target satellite, a metric used to describe the probability of collision for a particular space object, is growing at approximately the same rate. Using the orbital data from over ten thousand space objects in Space-Track.org’s publicly available version of the USSTRATCOM’s debris catalog, the number of near collisions can be calculated using a series of distance measurements between each object and a selected target satellite and determining the closest approach of each object over the course of one day. This paper uses the International Space Station as measured on May 1st, 2015 as a case study, which demonstrates the growing threat of collision in low-Earth orbit more generally from 1960 to 2015.