conditions on the lunar South Pole by teams from NASA and the ESA revealed a small number of illuminated ridges within 15 km of the pole, each of them much like an island of no more than a few hundred meters across in an ocean of eternal darkness, where a lander could receive near-permanent lighting (for ~70–90% of the southern lunar winter, and likely all of the southern lunar summer). The Malapert Mountain region, on the rim of the Malapert crater 122 km from the lunar south pole on the Earth-facing side, may also have high levels of illumination. One study estimates the Malapert Mountain region to receive less than full sunlight 11% of the time. Sunlight exposure varies by year due to the Moon's orbit being 1.5° off-plane with the Sun. 2005 estimates of sunlight coverage of the Malapert Mountain region found only six partially lit or unlit events that year: 0–159 hours of complete sunset per event and 41–199 hours of complete or partial sunset per event. A later study using a combination of both Clementine imaging and SELENE topographical data estimated only 74% of full sunlight for the year 2020. This study found that two points only ~8 km from each other along a straight ridge extending from Shackleton Crater at the Lunar South Pole are illuminated a combined ~94% of a lunar year. This is because both points cast shadows upon each other during different times of the lunar year, and only a few times of darkness occur when further peaks throw shadows over both of these points simultaneously. The data set from Lunar Reconnaissance Orbiter shows that some sites on the rim of Shackelton remain illuminated for 94% of a lunar year. The longest all three Shackleton outposts are eclipsed is 43 h. See also Crater of eternal darkness References External links The Peak of Eternal Light video by the European Space Agency. Dynamics of the Solar System Extraterrestrial mountains Geological features on the Moon