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.

Lunar permanently shadowed regions (PSRs) never see direct sunlight and are illuminated only by secondary illumination - light reflected from nearby topography. The ShadowCam imaging experiment onboard the Korea Pathfinder Lunar Orbiter is acquiring images of these PSRs. We characterize and discuss the nature of secondary illumination for the Shackleton PSR from ShadowCam radiance-calibrated images. We also use modeling to understand the magnitude and direction of the secondary illumination. Results from our analysis highlight the non-homogeneous, dynamic, and complex nature of PSR secondary lighting. Knowledge of the direction of the secondary illumination is crucial for reli-able interpretation of contrasts observed in ShadowCam images. This preliminary analysis of the floor of Shackleton crater from images acquired over multiple secondary illumination conditions does not reveal indications of exposed surface ice, even though temperatures are constantly below 110K.

Lunar polar volatiles, such as water ice, are essential lunar exploration objects. The conceptual design for China's Chang'E-7 lunar exploration mission to the South Pole was proposed. The mission comprises an orbiter, a lander, a rover, a leaper, and a relay satellite. The orbiter can provide high-resolution images to select a suitable landing site. The rover and leaper will be deployed for in-situ exploration in sunlit areas and permanently shadowed regions, respectively. The relay satellite will transmit all data to the ground. We calculated the accumulated illumination, as an engineering condition, within a 15 kmx15 km area partially covering the Shackleton crater from January 1, 2024, to December 31, 2026. Two potential landing sites-areas SR1 and CR1-were analyzed in detail by comparing their average illumination rate, slope, and distance to the exploration target. Additionally, we simulated the electric field of the Shackleton crater within a 37 kmx27 km area, considering the effect of the plasma wake on the electric field in shadowed areas. The results show that the maximum surface potential near the rims is less than 2.1 V, while the minimum surface potential at the bottom of the crater can reach as low as -500 V due to the plasma wake effect. Therefore, a risk assessment is necessary, especially for the exploration of the leaper at the bottom of the Shackleton crater.

The Moon's permanently shadowed regions (PSRs) never see direct sunlight and are illuminated only by secondary illumination - light reflected from nearby topography. Modeling the secondary illumination enables our understanding of the illumination and thermal condition at the PSRs and can be computed for any point in time by using topography. The ShadowCam instrument onboard the KPLO spacecraft is now in the nominal mission phase, acquiring images of the PSRs. We compare the secondary illumination model generated images with true high-resolution images of the Shackleton PSR acquired by ShadowCam.

Whether water molecules of cometary and/or solar wind origin migrated to and accumulated in cold permanently shadowed areas at the lunar poles has long been debated from the perspective of scientific interest and expectations for future utilization. Recently, high reflectance condition was observed inside the lunar South Pole Shackleton Crater for the 1064.4 nm of the Lunar Orbiter Laser Altimeter on the Lunar Reconnaissance Orbiter, and the high reflectance was explained to perhaps be due to a surface frost layer in excess of 20% water-ice. Here we investigate the crater with the Selenological Engineering Explorer Multi-band imager that has nine bands in the visible to near-infrared range, including a 1050 nm band (62 m/pixel resolution). Part of the illuminated inner wall of Shackleton Crater exhibits high reflectance at 1050 nm but also exhibits the diagnostic 1250 nm spectral absorption, a signature that is consistent with naturally bright purest anorthosite.