Abstract:

We present an optimization-based approach for fuel-efficient spacecraft rendezvous to Gateway, a lunar space station architecture based on a near rectilinear halo orbit (NRHO) around the Earth-Moon L2 point. Our main contribution is a method that ensures safety at all times in the presence of Gaussian uncertainty while incorporating disturbance compensation feedback through correction maneuvers. Specifically, the approach: i) ensures passive safety and satisfies path constraints at all times, ii) satisfies the specifications for critical decision points along the trajectory, and iii) accounts for common uncertainties arising from orbital insertion maneuvers, actuation, and navigation measurements. To account for these uncertainties, we use both chance constraints and disturbance compensation feedback to bound the effects of errors. We leverage sequential convex programming (SCP) together with an isoperimetric reformulation of continuous-time path constraints, including passive safety, to eliminate the risk of inter-sample constraint violations common in existing methods. This enables sparse time discretization that supports efficient offline mission design and analysis and aligns with operational preferences for less frequent control actions. We demonstrate the method on a case study representative of Gateway rendezvous operations.