Multi-mission, multi-sensor study of the Shackleton Crater constrained for volatiles with emphasis on albedo distribution of the Lunar South Pole

Abstract

Shackleton Crater on the Moon is named in honor of a pivotal figure of the Heroic Age of Antarctic Exploration Sir Ernest Henry Shackleton. The Crater was formed about 3.6 billion years ago at the Lunar South Pole. Due to the low (1.5°) tilt of the lunar axis of rotation, the interiors of the crater receive almost no direct sunlight and observations by passive hyperspectral sensors are only possible due to reflected light. Active sensors are however able to illuminate the interior surface of the crater and make observations. Here we present the results of study of the crater using data from multiple sensors onboard two missions of Indian Space Research Organization (ISRO) and National Aeronautics and Space Administration (NASA). Hyperspectral observations from Moon Mineralogy Mapper (M3) on-board Chandrayaan-1, temperature from Diviner Lunar Radiometer Experiment (DLRE), albedo from Lunar Orbiter Laser Altimeter (LOLA) and Off/On band ratios from Lyman-Alpha Mapping Project (LAMP) on board Lunar Reconnaissance Orbiter (LRO) have been used. Permanently Shaded Regions (PSRs) are identified and Shackleton has been found, as reported, to be a PSR. Emphasis has been laid on LOLA albedo analysis of lunar south pole (80°-90° South). It is observed that the Shackleton Crater exhibits significantly higher albedo compared to its surrounding regions. Some regions exhibit albedo even higher than the Shackleton Crater in the lunar south pole region. The findings of high albedo, coupled with high Off/On band ratio of LAMP, extremely low DLRE temperatures in the permanently shaded regions and detection of hydration features in the M3 hyperspectral data suggests higher probability of hydration in the Shackleton Crater.