Collision and debris hazard assessment for a low-earth-orbit space constellation

In an effort to assess issues associated with a low-Earth-orbit constellation development, the potential collision of the constellation spacecraft with background trackable and smaller debris objects was examined. The background flux of debris was projected to the year 2002. The collision potential with a Space Station sized object passing through the constellation was also determined. A modified analytical approach was used to estimate the collision probabilities in Earth orbit based on the concepts from the asymptotic theory of extreme-order statistics. The approach is based on a propagation or a Monte Carlo simulation of the orbital motion of a spacecraft and a population of objects in orbit. An empirical set of close approach distances is obtained at random times from which the probability of collision and the rate of encounters at specified ranges is determined, The encounter rate within a specified range was determined and found to compare favorably with that obtained from a close approach determination software package.