Fig. 4: Parameter analysis of the lunar regolith at the Longji site.

a Lunar regolith bearing parameters analysis in comparison to terrestrial soil samples. The bearing parameters of lunar regolith at the Longji site are estimated to be within the rectangle area (in light orange) framed by three orange boundary dots. Black scatter points represent bearing parameters of terrestrial soil samples, and dashed-dotted lines represent typical bearing parameters of terrains on the Moon (N = 1.0, K_s = 820 kPa m^-N). LLL represents Land Locomotion Lab. WES represents Waterways Experiments Stn. N is the variable sinkage exponent of wheel-terrain interaction; for black scatter points and dashed-dotted lines, N = n (intrinsic sinkage exponent of the terrain). The bearing and shearing parameters of terrestrial soil samples are listed in Supplementary Table 9. b Lunar regolith shearing parameters analysis in comparison to terrestrial soil samples. The shearing parameters of lunar regolith at the Longji site are estimated to be within the rectangle area (in light orange) framed by two orange boundary dots. Black scatter points represent shearing parameters of terrestrial soil samples, and dashed-dotted lines represent typical shearing parameters of terrains on the Moon (c = 520 Pa, φ = 42°). c Lunar regolith shearing parameters of the Longji site compared with those estimated in other lunar exploration missions. The shearing parameters of soil samples on other lunar landing sites are listed in Supplementary Table 10. Each error bar defines the upper and lower bound of c and φ estimated in different lunar exploration missions with different methods, and the center point is the median value of the parameter range. d Lunar regolith lateral parameters analysis in comparison to the lunar simulants. The shearing parameters of lunar regolith at the Longji site are estimated to be within the rectangle area (in light orange) framed by two orange boundary dots. Dashed-dotted lines represent the lower and upper bound of K_y according to experience (K_y = 13 mm, K_y = 40 mm). The lunar simulant is equivalent to FJS-1⁸⁵, whose material components and mechanical characteristics (Supplementary Table 12) are similar to those of the real lunar soil, as reported in ref. ⁴⁹. Another simulant (Supplementary Table 13) is standard commercial experimental sand, numbered HIT-LSS2, whose particle size is set to be uniform for repeatability of terramechanics experiments. The lateral parameters of the lunar simulant and the standard commercial experimental sand are from refs. ^43,86.