Novel Guidance Schemes For GT Missions Master Thesis

Abstract

Ensuring the long-term stability of a gravity-tractor spacecraft near a binary asteroid demands guidance laws that can withstand the nonlinear, multi-body dynamics and uncertainties of space. We derive and compare three controllers the PD+, the LQR, and a High-Order Sliding-Mode Controller (HOSMC) with super-twisting, for both a two-body approximation and the full circular restricted three-body problem. Simulations will reveal that while the PD+ is simple and the LQR is optimal near its linearization point, only the HOSMC attains rapid, accurate convergence from large deviations and under significant unmodeled perturbations, with the super-twisting sliding-mode law thus representing a promising guidance scheme for future gravity-tractor missions in binary systems.

Ensuring the long-term stability of a gravity-tractor spacecraft near a binary asteroid demands guidance laws that can withstand the nonlinear, multi-body dynamics and uncertainties of space. We derive and compare three controllers the PD+, the LQR, and a High-Order Sliding-Mode Controller (HOSMC) with super-twisting, for both a two-body approximation and the full circular restricted three-body problem. Simulations will reveal that while the PD+ is simple and the LQR is optimal near its linearization point, only the HOSMC attains rapid, accurate convergence from large deviations and under significant unmodeled perturbations, with the super-twisting sliding-mode law thus representing a promising guidance scheme for future gravity-tractor missions in binary systems.