Impulsive Relative Motion Control with Continuous-Time Constraint Satisfaction for Cislunar Space Missions

TL;DR

This paper introduces a Sequential Convex Programming method for impulsive relative motion control in cislunar space, ensuring continuous constraint satisfaction with improved computational efficiency for space missions.

Contribution

It presents a novel SCP-based approach that optimizes impulsive maneuvers with continuous-time constraint satisfaction, outperforming existing methods in computational speed.

Findings

Validated on a selenocentric orbiting problem.

Achieved significant reduction in CPU time per iteration.

Demonstrated continuous constraint satisfaction over the entire time horizon.

Abstract

Recent investments in cislunar applications open new frontiers for space missions within highly nonlinear dynamical regimes. In this paper, we propose a method based on Sequential Convex Programming (SCP) to loiter around a given target with impulsive actuation while satisfying path constraints continuously over the finite time-horizon, i.e., independently of the number of nodes in which domain is discretized. Location, timing, magnitude, and direction of a fixed number of impulses are optimized in a model predictive framework, exploiting the exact nonlinear dynamics of non-stationary orbital regimes. The proposed approach is first validated on a relative orbiting problem with respect to a selenocentric near rectilinear halo orbit. The approach is then compared to a formulation with path constraints imposed only at nodes and with mesh refined to ensure complete satisfaction of path constraints over the continuous-time horizon. CPU time per iteration of 400 ms for the refined-mesh approach reduce to 5.5 ms for the proposed approach.