Next-generation Mars EDL GNC: Challenges and solutions

All Mars landers to date continue to rely on the entry, descent and landing (EDL) technologies developed for the Viking missions in the mid-seventies of the last century. Viking-like landers adopt the inertial navigation and unguided entry mode, which lead to the larger landing error ellipse and lower elevation landing site restriction. Next-generation Mars missions requires the capability of pin-point landing (safe landing within tens of meters to 100 m of a pre-selected target site), the current Mars EDL guidance navigation and control (GNC) system cannot meet the requirements. In this paper, main challenges that impact on Mars EDL GNC are analyzed firstly. Then, some potential solutions are proposed to circumvent the challenges. Integrated navigation schemes are presented to improve the navigation accuracy. At the same time, active entry guidance schemes are proposed to improve the guidance performance with the larger parameter uncertainties using robust and adaptive control theory. Fault-tolerant control strategies are given to enhance the reliability, and the autonomous hazard detection and avoidance scheme is also developed to improve the safety of landing.