Target sequence optimization for multiple debris rendezvous using low thrust based on characteristics of SSO

A method is proposed to select the target sequence for a $J_2$-perturbed multiple debris rendezvous mission aimed at removing dozens of debris from several thousand debris candidates running on sun-synchronous orbits (SSO). The solving methodology proceeds in two steps: Firstly, the variance of the right ascension of ascending node (RAAN) of the debris group is used for narrowing down the potential debris candidate; secondly, the debris of the candidate group that has closest RAAN to the current debris is chosen as the next debris. The low thrust near-minimum-fuel trajectories of each rendezvous leg are obtained by the indirect optimization method. The proposed approach is demonstrated for the problem of the 8th China Trajectory Optimization Competition (CTOC). The radar cross section (RCS) of the debris is also considered in the first step since the primary performance index of the competition is to maximize the total RCS of the debris visited. The results show that the proposed approach achieves better performance within a competition period. Of the many rendezvous sequences found, the best one submitted for the competition obtained a total RCS of 184 by accomplishing rendezvous with 70 debris within a transfer duration of one year.