Near-optimal maneuver design for high-accuracy trans-lunar injection with highly elliptical phasing loops

To match the trans-lunar injection with high accuracy, a near-optimal orbit control method for phasing loops is proposed. Sensitivity analysis was performed based on Gauss’s variational equations, and a near-optimal orbit control strategy was developed. A sequential shooting method was proposed to reduce the dimensions of each shooting problem and improve convergence. To satisfy the accessibility requirements of ground facilities, a maneuvering location adjustment strategy is proposed. The advantage of the delta-V saving of the near-optimal method was verified by comparing with the differential correction method. The robustness of the practical method was verified using Monte Carlo simulations with high-fidelity dynamics. The results of this study can be applied to midcourse correction of phasing loops before the trans-lunar injection of a lunar probe.