RAPID LOCAL TRAJECTORY OPTIMIZATION IN CISLUNAR SPACE

This paper presents an algorithm for rapid local trajectory optimization around a reference using the reference trajectory’s higher-order state transition tensors (STTs) to approximate the local dynamics, and differential dynamic programming (DDP) to optimize the controls. The algorithm is applied to a variety of transfers in cislunar space within the context of the Earth-Moon circular restricted threebody problem. Continuous-thrust transfers both arriving at and departing nearrectilinear halo orbits are examined. The STT/DDP algorithm is shown to perform more accurately than linearized methods for these types of transfers, while requiring significantly less computational power than standard numerical optimization methods. The method is promising for rapidly conducting large-scale tradeoff analyses for transfers with varying or uncertain departure and arrival conditions. In addition, the proposed method could be used for on-board guidance applications with limited computational resources, or time-critical trajectory re-planning scenarios.