Martian subsurface water ice prediction at the Tianwen-1 mission landing site

One of the important sub-tasks of China's ongoing Tianwen-1 exploration mission is to find water ice on Mars. We have predicted the distribution of shallow subsurface water ice at the Tianwen-1 landing site to provide reference information for the mission. A detailed analysis shows that only for an exceptionally favorable combination of slope, albedo, and thermal inertia would perennial near-surface ice be expected at the Tiwanwen-1 landing site and the Zhurong rover is hardly to carry out in-situ searching for ice at steep slopes with dust-mantled surfaces, while seasonal ice is very likely to be found in winter in Tianwen-1 landing area with appropriate terrain conditions. With the interaction of a hygroscopic salt, the transient diurnal ice can exist and experience phase transitions. Notably, under the influence of Ca (ClO4)2, liquid brine may exist in diurnal cycles even on the hottest day of Mars.