Abstract: An autonomous high fault tolerance touchdown strategy is proposed in this paper for the soft landing stability and safety. In the process of the entry, descent and landing, the touchdown monitor signals may be triggered for the Mars environment of large impact, high dynamic and strong vibration. A practical method which combines the touchdown monitor signals with the acceleration information and the accurate navigation information is proposed to guarantee the accuracy of decision. Meanwhile, an optimized touchdown shutdown timing control strategy is proposed to realize the autonomous management and fault tolerant reconstruction of the touchdown shutdown. The test and actual flight results show that the proposed autonomous high fault tolerance touchdown strategy can satisfy the requirement of explorer for soft landing touchdown.

Key words: Tianwen 1 Probe, Soft landing, Shutdown at touchdown, Online decision making