Potential landing sites characterization on lunar south pole: De-Gerlache to Shackleton ridge region

The lunar south polar region is of specific interest with a much higher probability for finding water ice and volatile resources in the permanently shadowed regions (PSRs). Here, the uneven topography coupled with very low axial inclination of the Moon of similar to 1.5(o) helps in maintaining a perennial temperature below 110 K in relatively broad areas. Along with the possibility of finding water ice and other volatiles that can be used for future explorations, the south polar region is expected to be compositionally diverse being situated inside the South Pole Aitken Basin (SPA). Though several lunar polar missions were planned, none of them have yet experienced and explored the unique polar environment in-situ. Several sites have been identified majorly based on technical feasibility of landing. The polar sites are challenging to land due to the difficult terrain and limited information about its characteristics. In this study, we selected a ridge region connecting two PSRs: de-Gerlache and Shackleton, and evaluated four sites in that ridge and prioritized them based on the expected scientific outcomes and feasibility to access a PSR for volatile detection and quantification. Our detailed analysis of landing sites is based on terrain characteristics, which include slope, illumination, surface roughness, surface temperature, accessibility to nearby PSRs, compositional diversity, and trafficability. Moreover, multiple micro PSRs have been identified in close vicinity of four landing sites that can potentially trap water ice and other volatiles. We find that the site C1 (-136.2 degrees, - 89.406 degrees) situated on the ridge connecting de-Gerlache and Shackleton, and site D (-87.514 degrees, -89 degrees) situated on the rim of de-Gerlache are the most promising sites that can be considered for near future polar exploration missions. These sites provide opportunity of exploration utilizing solar power without compromising on scientific outcomes. Both the sites are found to be in close vicinity of PSR providing opportunities to sample volatiles. The sites C1 and D provide a good alternative to site S (-158.162 degrees, -89.769 degrees) located on Shackleton crater rim, which is considered to be scientifically enriched but technically challenging for landing.