Probability of Collisions in the Geostationary Ring

Abstract

Geostationary satellites not removed from the geosynchronous altitude at the end of their useful life will expose future spacecraft orbiting in this unique region to a continual collision hazard. The probability of a collision occurring before the end of this century is less than 2 x 10 ~ , unless large space structures such as solarpower satellites become operational, in which case collisions would likely occur every few years. Fundamental data on the collision probabilities are derived from deterministic orbit propagation for a representative sample of uncontrolled objects using an intersection process in which the active satellites are described by a probability distribution within the geostationary ring. The study clearly points out that all geostationary satellites should be removed from the ring at the end of their operational lifetime in order that the collisional risk remains within acceptable bounds in the future. The cost of this remedy amounts to no more than that of one month of active station-keeping for present-day satellites.