Abstract:The lunar distant retrograde orbit (DRO) can serve as a crucial transfer hub for future lunar development and manned missions to Mars, making its airline-flight-mode transfers essential for sustained transportation and resource supply. To address challenges associated with the airline flight mode—such as limited transfer time of flight and extensive time window requirements—we employ lunar gravity assist techniques alongside a multi-impulse trajectory optimization method utilizing a perturbation Lambert solver to minimize fuel consumption for individual transfer trajectories. Furthermore, a local optimization method is implemented to schedule the docking time window sequence for the DRO, achieving comprehensive optimization of multiple round-trip transfer trajectories. Simulation shows that there is a specific time window where late departing spacecraft arrive at the DRO service station earlier, resulting in lower overall fuel consumption for the mission. The local optimization method for the docking time window sequence can achieve an overall fuel savings of 2.5%.