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.

Chandrayaan-1, the first Indian planetary exploration mission, will carry out high resolution remote sensing studies of the moon to further our understanding about its origin and evolution. Hyper-spectral imaging in the UV-VIS-NIR region using three imaging spectrometers, along with a low energy X-ray spectrometer will provide mineralogical and chemical composition of the lunar surface at high spatial resolution. A terrain mapping camera will provide high resolution three-dimensional images of the lunar surface and will be complemented by a laser ranging instrument that will provide lunar altimetry. Three payloads - a high energy X-gamma ray spectrometer, a sub-keV atom reflecting analyser, and miniature imaging radar - will be used for the first time for remote sensing exploration of a planetary body. They will investigate transport of volatiles on the lunar surface, presence of localized lunar mini-magnetosphere and possible presence of water ice in the permanently shadowed lunar polar region respectively. A radiation dose monitor will provide information on energetic particle flux en route to the moon and in lunar orbit. An impact probe carrying an imaging system, a radar altimeter and a mass spectrometer will be released from the spacecraft to land at a predestinated lunar site. The design of the one tonne-class spacecraft is primarily adapted from flight proven Indian Remote Sensing satellite bus with several modifications that are specific to the lunar mission. The spacecraft was launched by using a variant of the indigenous Polar Satellite Launch Vehicle (PSLV-XL) and placed in a 100 km circular polar orbit around the moon with a planned mission life of two years. An Indian Deep Space Network and an Indian Space Science Data Center have been established as a part of Chandrayaan-1 mission and will cater to the need of future Indian space science and planetary missions.