Real-time autonomous guidance generation around small bodies via Sequential Convex Programming

This paper introduces a novel approach to real-time convex guidance generation for spacecraft navigating in proximity to small celestial bodies, such as asteroids or small moons. The proposed method leverages Sequential Convex Programming (SCP) techniques to model and navigate irregular gravity fields encountered near these bodies, addressing the strong nonlinearities by iteratively refining a convex guidance sub-problem. The key contribution is the development of an adaptive algorithm that autonomously determines the optimal time of flight and dynamically adjusts to the gravitational environment, enabling spacecraft to autonomously generate robust guidance trajectories in real time including a non-convex collision avoidance constraint. The algorithm is developed in library-free C code to be ready for real-time embedded implementation and gain a realistic understanding on possible onboard application. The efficacy of the proposed method is validated for both asteroids and small moons through numerical simulations including sliding-mode close-loop control, showcasing high accuracy, computational efficiency, and flexibility to different environments.