Missed Thrust Analysis and Design for Low Thrust Cislunar Transfers

This paper details the analysis of the missed thrust problem for low thrust cislunar transfers. Missed thrust analysis is completed for a reference NRHO to DRO transfer that is designed to maximize the final mass without consideration of robustness to unexpected loss of thrust. A new missed thrust design method is presented to include the robustness of the transfer as part of the optimization problem by including a minimal number of branching trajectories tied to the start of thrust arcs in the reference transfer and optimizing them all simultaneously. Results from variations of this approach are presented for and compared to the reference transfer designed without consideration for missed thrust. The results show that this new method can reduce the additional propellant required for recovery from an unexpected 7-day outage by up to 90% without significant increase to the propellant required to complete the reference transfer.