Trajectory optimization and explicit guidance for rendezvous with Gateway using finite thrust

This research assesses the effectiveness of a closed-loop iterative Lambert-based guidance in cislunar space, to achieve rendezvous with Gateway. Orbit dynamics is simulated in a high-fidelity ephemeris-based framework, employing Modified Equinoctial Elements as the state variables. First, optimal two-impulse transfers from low lunar orbit to Gateway are identified, using an effective approach based on a heuristic algorithm and backward propagation, while assuming different rendezvous positions. Then, a computationally efficient Lambert-based guidance algorithm is successfully tested through Monte Carlo campaigns, in the presence of nonnominal conditions related to actuation, using either the impulsive thrust approximation and finite thrust.