page_title: Geology of the Moon
section_title: Lunar lava tubes
hierarchical_section_title: Geology of the Moon / Lunar landscape / Lunar lava tubes
caption_attribution_description: English: Spectacular high Sun view of the Mare Tranquillitatis pit crater revealing boulders on an otherwise smooth floor. Image is 400 meters wide, north is up, NAC M126710873R. When the Sun is well overhead, the floor of the Mare Tranquillitatis pit is illuminated. With an incidence angle of 26.5° and a shadow of 55 meters (180 feet), scientists can estimate the depth to be a bit over 100 meters (328 feet). That estimate is from the edge of the shadow, which begins a slightly downslope from the gradual margin of the pits. When measured from the level of the surrounding mare plain, the depth of the pit is even greater. Compare this depth to the width, which ranges from 100 to 115 meters (328 to 377 feet) across the sharp precipice. NASA's Goddard Space Flight Center built and manages the mission for the Exploration Systems Mission Directorate at NASA Headquarters in Washington. The Lunar Reconnaissance Orbiter Camera was designed to acquire data for landing site certification and to conduct polar illumination studies and global mapping. Operated by Arizona State University, LROC consists of a pair of narrow-angle cameras (NAC) and a single wide-angle camera (WAC). The mission is expected to return over 70 terabytes of image data. The description is copied from en:File:Mare Tranquillitatis pit crater.jpg.
context_page_description: The geology of the Moon is quite different from that of Earth. The Moon lacks a true atmosphere, which eliminates erosion due to weather; it does not have any known form of plate tectonics, it has a lower gravity, and because of its small size, it cooled more rapidly. The complex geomorphology of the lunar surface has been formed by a combination of processes, especially impact cratering and volcanism. The Moon is a differentiated body, with a crust, mantle, and core.
  Geological studies of the Moon are based on a combination of Earth-based telescope observations, measurements from orbiting spacecraft, lunar samples, and geophysical data. Six locations were sampled directly during the crewed Apollo program landings from 1969 to 1972, which returned 380.96 kilograms of lunar rock and lunar soil to Earth. In addition, three robotic Soviet Luna spacecraft returned another 326 grams from 1970 to 1976. The Moon is the only extraterrestrial body for which we have samples with a known geologic context. A handful of lunar meteorites have been recognized on Earth, though their source craters on the Moon are unknown.
context_section_description: Lunar lava tubes form a potentially important location for constructing a future lunar base, which may be used for local exploration and development, or as a human outpost to serve exploration beyond the Moon. A lunar lava cave potential has long been suggested and discussed in literature and thesis. Any intact lava tube on the Moon could serve as a shelter from the severe environment of the lunar surface, with its frequent meteorite impacts, high-energy ultraviolet radiation and energetic particles, and extreme diurnal temperature variations. Following the launch of the Lunar Reconnaissance Orbiter, many lunar lava tubes have been imaged. These lunar pits are found in several locations across the Moon, including Marius Hills, Mare Ingenii and Mare Tranquillitatis.
caption: Lunar pit in Mare Tranquillitatis
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