Abstract:

A method for manned lunar landing mission trajectory and trans-lunar window integrated design is proposed considering with the task background and project constraints. Through the two coordinate rotations, circumlunar free-return trajectory parameter is decoupled to the independent variables in perilune. Free-return trajectories parameters and window quick search algorithm matching with low earth orbit (LEO) plane are achieved based on 4 stage two-body patched-conic approach under the double two-body model, and the result can be treated as the initial iterative value in the next step, which a free-return trajectory with high precise orbit dynamic model is obtained by sequential quadratic programming (SQP), a free-return trajectory and zero-window approach to LEO phase are gotten from the generation of the 90min neighborhood trajectories. The design example demonstrates the precision and rapidity of the circumlunar free-return trajectory and trans-lunar window approach with complex task background and rigorous project constraints for manned lunar landing mission.

Key words: Manned lunar landing, Circumlunar free-return, Trajectory design, Low earth orbit connection, Trans-lunar window