Statistical Conjunction Analysis and Modeling of Low-Earth-Orbit Catalogued Objects

摘要

The number of space debris objects in the low Earth orbits, especially in the sun synchronous orbits, is increasing, and the breakups in 2007 have added more risk to the satellites in this region. It is necessary to study the risk of conjunctions in these orbits to plan a future course of action regarding the control and mitigation of space debris objects. A statistical approach to obtain the number of conjunctions in a prescribed altitude bin considering various inclination bands is presented in this paper. The low Earth orbits, which are affected the most by the accumulation of space debris objects, are analyzed with special emphasis on sun synchronous orbits. The study is based on the catalogued objects from the two line element sets. It is observed that, after the major breakups in 2007, the number of conjunctions in the sun synchronous orbital region is highly significant. The second part of the study concentrates on the modeling aspects of spatial density and brings out a stochastic model based on a mixture of Laplace distributions. It is noted from the model that the fragmentation events in low Earth orbit during 2007 have redefined the pattern of spatial density distribution in the region below 1100 km.