Efficient selection of asteroid landing sites using composite guidance vectors

The complex topographies on the asteroid surface are not only the main object to avoid in the landing process, but also the key target of observation to provide navigation information. This paper focuses on the need of autonomously selecting a landing site during asteroid exploration, and reveals the guiding effects of the environment on mission decision-making through a vectorized landing site selection. Specifically, the lander's navigation observation performance on the way to different landing locations is taken into account. A quantified observation efficiency index is formulated through a prediction of the observable navigation features in the transfer process. Combining landing safety and observation efficiency evaluation results, the proposed method constructs a composite guidance vector field on the safe areas, where the guidance vectors shed light on the search direction of a superior landing site. Using the guidance vectors, a step-diminishing random search algorithm is designed to realize an efficient search for the optimal solution. The simulation results demonstrate that the proposed method can rapidly find a satisfactory landing site in the complex topography, balancing both landing safety and observation requirements for asteroid landing missions.