Abstract: The environmental conditions of Mars landing missions are much different from that of Earth reentry missions, including the distance between the spacecraft and the Earth, the atmosphere, landform, aerodynamic forces, thermal effects. Therefore there are more autonomy requirements, more flight phases, more uncertainties in modeling and analysis, and more difficulties in validation of the flight sequence. Firstly the challenges of Mars landing missions are summarized in this paper. Then the key issues for Mars landing missions are analyzed according to the phases of the landing process. Finally suggestions and proposals for further development for Mars landing technologies are given.

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