Spacecraft rendezvous trajectory safety quantitative performance index eliminating probability dilution

In view of the probability dilution problem of the existing quantitative indexes of rendezvous trajectory safety performance using collision probability, this paper proposes a new quantitative index of rendezvous trajectory safety performance by well combining collision probability with warning threshold. The proposed new index increases monotonously as the position errors of the chaser spacecraft increase, therefore it can effectively overcome the problems of the reduction in the largest performance value and the advancement in the most dangerous time induced by the probability dilution. The proposed new index is applied to the safety design of close range rendezvous missions. The mission’s safety requirements for initial navigation precision and the safe region of initial and final keeping points’ positions with a certain navigation precision are analyzed, and several valuable conclusions about the relation between position navigation precision and velocity navigation precision as well as the relation between keeping points’ positions and navigation precision are obtained.