Optimization and Analysis of NRHO Two-impulsive Phasing Trajectory in Cislunar Space

During the construction and operation of the lunar gateway station under the U.S. Artemis program, numerous cargo and crew rendezvous and docking missions will be executed in the Near-Rectilinear Halo Orbit (NRHO). To address the phasing trajectory optimization problem in NRHO, a method based on the Circular Restricted Three-Body Problem (CRTBP) model is adopted. Initially, the transfer time is traversed using a trust-region algorithm. This step is critical to determining the transfer time that minimizes fuel consumption. Following the exploration of transfer times, a nonlinear optimization algorithm is applied to locally correct position errors along the trajectory. This local optimization fine-tunes the spacecraft’s path, ensuring precise alignment during the rendezvous. Finally, the nonlinear equations are solved iteratively to reduce the velocity increment required for the maneuver. This reduction in velocity increment is key to achieving low-fuel consumption during the NRHO phasing process. In addressing the phasing cost issue, this method is further utilized to analyze various scenarios on the NRHO, taking into account different transfer times and phase relationships. The analysis demonstrates that the algorithm boasts high computational efficiency, reducing computation time by 53.2% compared to a genetic algorithm. It is also observed that the longer the transfer time, indicating an increase in the number of transfer orbit revolutions, the smaller the velocity increment consumed during the maneuver becomes. Additionally, when the target spacecraft exhibits a phase lag, opting for a phasing maneuver along the outer loop of the NRHO results in fuel savings, whereas if the target spacecraft’s phase is advanced, choosing the inner loop proves to be more fuel-efficient. Finally, the study notes that when the tracking spacecraft departs from the perilune, the consumed velocity increment is comparatively lower. This approach, therefore, provides an effective and efficient solution for optimizing NRHO phasing, ensuring reliable rendezvous operations with reduced fuel consumption and enhanced computational performance.