Analysis of the permanently shadowed region of Cabeus crater in lunar south pole using orbiter high resolution camera imagery

The Orbiter High Resolution Camera (OHRC) on-board India's Chandrayaan-2 orbiter mission had acquired two images of the Permanently Shadowed Region (PSR) and adjacent area of Cabeus crater at an unprecedented resolution (<0.3 m/pixel). Numerous small features, such as meter scale boulders, craters, and slope-normal lobes were identified in these images. Boulders and craters as small as 1.5 m and 1.8 m, respectively, were identified in PSR making this size limit two times better than the currently reported values (>3 m for boulders and > 4 m for craters). The crater size distributions in PSR and Non-PSR regions were found to be alike in the size range of 3-20 m. We identified over 20% more smaller craters (<3 m) in the Non-PSR areas as compared to the PSR because of the higher illumination in the Non-PSR. Slope-normal lobes (potentially related to the presence of ice) were present in PSR as well as in Non-PSR areas. The impact generated debris (potentially) of Lunar Crater Observation and Sensing Satellite (LCROSS) impactors were also identified inside the Cabeus crater. Finally, it is concluded that OHRC is one of the most suitable camera, presently available on any orbiter around the Moon, for the imaging of PSRs to facilitate the study of small surface features that might be related to surface/subsurface ice, and equally important for the trafficability inside the PSRs.