Design of contingency point return trajectory in the lunar orbit insertion phase for crewed lunar exploration missions

To satisfy the requirement of contingency rescue in the lunar orbit insertion phase for crewed lunar exploration missions, this paper designs the contingency point return trajectory. First, according to different failure situations of the main propulsion system in the lunar orbit insertion phase, different types of contingency return modes are analyzed and summarized. Second, considering the terminal constraints of point return, a calculation model of the contingency point return trajectory is established, and a serial optimization process is adopted to obtain a high-fidelity solution. Finally, a numerical simulation is used to verify the model. The simulation results indicate that this model can be applied to determine the contingency point return trajectories under different situations in the lunar orbit insertion phase and demonstrate the validity and feasibility of the trajectory calculation model proposed in this paper. The research conclusions can provide a reference for the design of contingency rescue schemes in the lunar orbit insertion phase for crewed lunar exploration missions.