Online landing site selection considering maneuverability constraint during mars powered descent phase

In Mars landing process, smaller hazards like rocks and craters can only be detected when the vehicle is near the surface. The original landing point might be found dangerous and thus the onboard selection of a new landing site and a real-time trajectory generation become the key to the success of the whole mission. In this paper, an autonomous online safe landing site selection considering maneuverability constraint during powered descent phase is proposed. The new landing site is selected based on a novel criterion called Landing Site Selection Index (LSSI). The index includes not only factors like safety of the terrain in view and terminal motion state, but also the maneuverability of the vehicle. A real-time slidingmode guidance is adopted to transfer the vehicle to the updated destination. The online selection and transfer process ensures the safety of the landing mission from multiple aspects. Further Monte Carlo simulations show the effectiveness and robustness of the scheme.