Continuous-Time Successive Convexification for Passively-Safe Spacecraft Rendezvous on a Near Rectilinear Halo Orbit

This paper presents an optimization-based method for spacecraft rendezvous to the Gateway that (i) enforces passive safety and an approach-cone path constraint in continuous time, (ii) satisfies decision-point specifications, and (iii) accounts for NRHO insertion, actuation, and navigation uncertainties via chance constraints and stabilizing feedback. The approach employs sequential convex programming within the continuous-time successive convexification (ct-SCvx) framework, in which continuous-time path constraints are reformulated as isoperimetric integral constraints, thereby decoupling continuous-time feasibility (solution quality) from the chosen time-discretization density. In addition, time dilation is used to treat the actuation time instants as optimization variables. A numerical case study for an NRHO apolune rendezvous to the Gateway, validated through Monte Carlo simulation, demonstrates satisfaction of passive-safety and approach-cone constraints with high probability and with fuel use comparable to recent NRHO rendezvous studies.