Lux Aeterna At The Moon's South Pole


The rim crest and upper part of the rim of Shackleton crater; the south pole is located on the rim near the upper right corner of the image. The upper slopes of the crater's interior are very steep, often exceeding 30 degrees. The shadowed interior never receives direct sunlight; image width approximately 11 kilometers M1195011983LR [NASA/GSFC/Arizona State University].

Close to the south pole, the Sun never rises far from the horizon, but as the Moon spins on its axis, the direction to the Sun changes.

Local ridges cast ragged shadows that shift dramatically over the landscape as the Sun circles the horizon. Many high points are illuminated for extended periods of time. Conversely, low areas near the poles remain in darkness all year. Areas that never receive direct sunlight are called Permanently Shadowed Regions (PSRs); the interior of Shackleton crater is one such area.

Shackleton crater is 21 kilometers in diameter and over 4 kilometers deep. An elevated ridge runs roughly between Shackleton and de Gerlache craters, and the relatively high elevation of this landscape means that some portions are illuminated up to 90% of the time, but nowhere is permanently illuminated.

Future explorers could take advantage of this persistent illumination by setting up solar panels in several closely spaced locations providing nearly constant solar generated electricity. The proximity to Permanently Shadowed Regions in and around Shackleton crater adds scientific value to this destination, as PSRs are often home to compounds such as water ice that are not found elsewhere on the Moon, but which contain clues to the history of of inner Solar System water and other volatile elements.

A nearby, ready source of water-ice would also be of benefit to human surface activities, either as a consumable (air or water) or as spacecraft fuel.

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