The Descartes Highlands is an area of

lunar Lunar most commonly means "of or relating to the Moon". Lunar may also refer to: Arts and entertainment * ''Lunar'' (series), a series of video games * "Lunar" (song), by David Guetta * "Lunar", a song by Priestess from the 2009 album ''Prior t ...

highlands Highland is a broad term for areas of higher elevation, such as a mountain range or mountainous plateau. Highland, Highlands, or The Highlands, may also refer to: Places Albania * Dukagjin Highlands Armenia * Armenian Highlands Australia *Sou ...

located on the

near side The near side of the Moon is the lunar hemisphere that always faces towards Earth, opposite to the far side. Only one side of the Moon is visible from Earth because the Moon rotates on its axis at the same rate that the Moon orbits the Earth—a ...

that served as the landing site of the

American American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, pe ...

Apollo 16 Apollo 16 (April 1627, 1972) was the tenth human spaceflight, crewed mission in the United States Apollo program, Apollo space program, administered by NASA, and the fifth and penultimate to Moon landing, land on the Moon. It was the second o ...

mission in early 1972. The Descartes Highlands is located in the area surrounding Descartes crater, after which the feature received its name.

Geology

Two major formations dominate the Descartes Highlands area: the Cayley plains and the Descartes formation. The latter is composed primarily of highland

plateau In geology and physical geography, a plateau (; ; ), also called a high plain or a tableland, is an area of a highland consisting of flat terrain that is raised sharply above the surrounding area on at least one side. Often one or more sides ...

material, perhaps debris from large impact events—specifically the impact that formed

Mare Nectaris Mare Nectaris (Latin ''nectaris'', the "Sea of Nectar") is a small lunar mare or sea (a volcanic lava plain noticeably darker than the rest of the Moon's surface) located south of Mare Tranquillitatis southwest of Mare Fecunditatis, on the near ...

. North Ray and South Ray craters, the former sampled directly by the Apollo 16 crew, revealed a layering sequence, possibly an overlap of the Cayley and Descartes formations. The area of the Descartes Highlands is characterized by an undulating landscape covered with old and some new, sharp rimmed craters. Based upon findings during the Apollo 16 mission, some of the floors of these craters were covered with glass similar to that found at the Taurus-Littrow landing site on

Apollo 17 Apollo 17 (December 7–19, 1972) was the final mission of NASA's Apollo program, the most recent time humans have set foot on the Moon or traveled beyond low Earth orbit. Commander Gene Cernan and Lunar Module Pilot Harrison Schmitt walke ...

. According to Apollo 16 commander

John Young John Young may refer to: Academics * John Young (professor of Greek) (died 1820), Scottish professor of Greek at the University of Glasgow * John C. Young (college president) (1803–1857), American educator, pastor, and president of Centre Coll ...

, the arrangement of the glass gave it the appearance of dried mud. Before Apollo 16 sampled the Descartes Highlands, it was believed that

volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plat ...

material would be abundant in the area after visual analysis of the features there. It was thought that the formations in the area were formed by

lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or ...

s more

viscous The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the in ...

than the lavas that formed the Lunar mare. This was later disproved after the analysis of samples from the area. It was revealed that many of the rocks in the area are not volcanic in origin, but

breccia Breccia () is a rock composed of large angular broken fragments of minerals or rocks cemented together by a fine-grained matrix. The word has its origins in the Italian language, in which it means "rubble". A breccia may have a variety of ...

s composed of fragments from several lunar impacts. Astronauts Young and Duke visited

Sudbury Sudbury may refer to: Places Australia * Sudbury Reef, Queensland Canada * Greater Sudbury, Ontario (official name; the city continues to be known simply as Sudbury for most purposes) ** Sudbury (electoral district), one of the city's federal el ...

, Ontario, Canada in July 1971 to examine shatter cones. Sudbury is a site of a large meteor impact exhibiting substantial evidence of shatter cone geology. In the Descartes Highlands, it was determined that the region's topography was formed by meteor impact instead of volcanic activity.

Landing site selection

All of the preceding

Apollo Apollo, grc, Ἀπόλλωνος, Apóllōnos, label=genitive , ; , grc-dor, Ἀπέλλων, Apéllōn, ; grc, Ἀπείλων, Apeílōn, label=Arcadocypriot Greek, ; grc-aeo, Ἄπλουν, Áploun, la, Apollō, la, Apollinis, label= ...

landing missions sampled

Lunar mare The lunar maria (; singular: mare ) are large, dark, basaltic plains on Earth's Moon, formed by ancient asteroid impacts on the far side on the Moon that triggered volcanic activity on the opposite (near) side. They were dubbed , Latin for 'seas' ...

material, either directly or indirectly. A landing site in the Lunar highlands was to be selected with the goal of investigating the material located there. Two landing sites were given consideration to achieve this goal: the Descartes site and the crater Alphonsus. The Descartes Highlands was selected for the Apollo 16 mission in order to enable astronauts John Young and

Charles Duke Charles Moss Duke Jr. (born October 3, 1935) is an American former astronaut, United States Air Force (USAF) officer and test pilot. As Lunar Module pilot of Apollo 16 in 1972, he became the tenth and youngest person to walk on the Moon, at ...

to sample the prominent Descartes and Cayley formations concentrated in the area. Sampling these formations was a priority, as the two cover much of the near side of the Moon. Priority was also given to locating and obtaining samples of old highland material that was older than the Imbrium impact in order to give insight to the

geologic Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other E ...

timeline and composition of the Moon. North Ray and South Ray craters, both prominent features in the immediate landing area, were also prioritized because material from the prominent formations in the area had been naturally excavated there by the impacts that formed them.

References

{{Apollo program Geological features on the Moon LQ20 quadrangle 1972 in spaceflight Apollo 16

Geology

Landing site selection

See also

References