![Taurus-littrow-valley](https://upload.wikimedia.org/wikipedia/commons/b/b2/Taurus-littrow-valley.jpg)
Taurus–Littrow is a
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 ...
valley
A valley is an elongated low area often running between hills or mountains, which will typically contain a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers or streams ove ...
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 ...
at the coordinates . It served as the landing site for 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 17 mission in December 1972, the last crewed mission to the Moon.
The valley is located on the southeastern edge of
Mare Serenitatis
Mare Serenitatis (Latin ''serēnitātis'', the "Sea of Serenity") is a lunar mare located to the east of Mare Imbrium on the Moon. Its diameter is .
Geology
Mare Serenitatis is located within the Serenitatis basin, which is of the Nectarian epo ...
along a ring of
mountains formed between 3.8 and 3.9 billion years ago when a large object impacted the Moon, forming the Serenitatis basin and pushing rock outward and upward.
[
Taurus–Littrow is located in the Taurus mountain range and south of Littrow crater, features from which the valley received its name. The valley's name, coined by the Apollo 17 crew, was approved by the ]International Astronomical Union
The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...
in 1973.[
Data collected during Apollo 17 indicate that the valley is composed primarily of ]feldspar
Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) felds ...
-rich 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 ...
in the large massif
In geology, a massif ( or ) is a section of a planet's crust that is demarcated by faults or flexures. In the movement of the crust, a massif tends to retain its internal structure while being displaced as a whole. The term also refers to a ...
s surrounding the valley and basalt
Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...
underlying the valley floor, covered by an unconsolidated layer of mixed material formed by various geologic events. Taurus–Littrow was selected as the Apollo 17 landing site with the objectives of sampling highland
Highlands or uplands are areas of high elevation such as a mountainous region, elevated mountainous plateau or high hills. Generally speaking, upland (or uplands) refers to ranges of hills, typically from up to while highland (or highlands) is ...
material and young 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 plates a ...
material at the same location.
Geology
Formation and geography
Several million years after the formation of the Serenitatis basin, 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 un ...
s began to upwell from the Moon's interior, filling the basin and forming what is now known as Mare Serenitatis. As a result of these lavas, rock and soil samples from the area that were collected by Apollo 17 astronauts Eugene Cernan
Eugene Andrew Cernan (; March 14, 1934 – January 16, 2017) was an American astronaut, naval aviator, electrical engineer, aeronautical engineer, and fighter pilot. During the Apollo 17 mission, Cernan became the eleventh human being t ...
and Harrison Schmitt
Harrison Hagan Schmitt (born July 3, 1935) is an American geologist, retired NASA astronaut, university professor, former U.S. senator from New Mexico, and the most recent living person—and only person without a background in military aviation ...
provided insight into the natural history and geologic timeline of the Moon.[
Somewhere between 100 and 200 million years after the Serenitatis basin and Taurus–Littrow formed, the lavas that had seeped through the lunar crust began to flood the low-lying areas.] These lava flows were often accompanied by fire fountains that blanketed the surrounding area with tiny glass beads. These glass beads may present as a discoloration of the soil in which they came to rest, including that of the "orange soil" discovered by the Apollo 17 astronauts at Shorty crater
Shorty is a feature on Earth's Moon, an impact crater in the Taurus–Littrow valley. Astronauts Eugene Cernan and Harrison Schmitt visited it in 1972, on the Apollo 17 mission. It is the location of the famous "orange soil", which geologists be ...
. Most of these beads, however, are dark in coloration, to which the dark appearance of Mare Serenitatis from Earth can be attributed.[
]
The valley is elongated along an axis that roughly intersects with center of Mare Serenitatis. Large massifs are located on either side of the valley, named the North and South massifs, respective to their geographic location in relation to each other. The height of these massifs give the valley a depth greater than that of the Grand Canyon in the United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
.
Along the South Massif lies Bear Mountain, named after a mountain of the same name near Harrison Schmitt's hometown of Silver City, New Mexico
)
, population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano)
, seat = Santa Fe
, LargestCity = Albuquerque
, LargestMetro = Tiguex
, OfficialLang = None
, Languages = English, Spanish ( New Mexican), Navajo, Ke ...
. The sculptured hills and East massif make up the eastern edge of the valley and to the west, a scarp cuts across the valley floor and rises about two kilometres (1.2 miles) above it. The North and South massifs funnel into the main outlet of the valley, which in turn opens to Mare Serenitatis, such gap partially blocked by Family mountain.[
Based on Apollo 17 observations, the valley floor is generally a gently rolling plane. Boulders of various sizes, together with other geologic deposits, are scattered throughout the valley. At the ]ALSEP
The Apollo Lunar Surface Experiments Package (ALSEP) comprised a set of scientific instruments placed by the astronauts at the landing site of each of the five Apollo missions to land on the Moon following Apollo 11 (Apollos 12, 14, 15, 16, ...
lunar experiment deployment area, located west of the immediate landing site, the boulders average about four meters in size and are higher in concentration than in other areas of the valley.
The Tycho impact, which occurred between 15–20 and 70–95 million years ago, formed secondary crater
Secondary craters are impact craters formed by the ejecta that was thrown out of a larger crater. They sometimes form radial crater chains. In addition, secondary craters are often seen as clusters or rays surrounding primary craters. The study of ...
clusters in various locations of the Moon. Data from the examination of these clusters suggest that the central crater cluster in the valley formed as a result of that impact. Analysis of known secondary impact clusters resulting from the Tycho impact reveals that the majority of them have a downrange ejecta blanket
An ejecta blanket is a generally symmetrical apron of ejecta that surrounds an impact crater; it is layered thickly at the crater's rim and thin to discontinuous at the blanket's outer edge.
The impact cratering is one of the basic surface format ...
, or debris layer, with a distinctive 'birdsfoot' pattern. Apollo 17 observation data and comparison between the valley's central crater cluster and known Tycho secondary impacts indicate many similarities between them.[
The valley's central crater cluster has a 'birdsfoot' ejecta pattern that points in the direction of Tycho and the debris pattern of the light mantle points directly towards the South massif. The latter lends further support to the hypothesis that the light mantle formed as a result of an avalanche from the South massif, perhaps as a result of secondary Tycho impacts. Large-scale analysis suggests that the crater cluster may be part of a larger secondary Tycho cluster, which may include craters on the North massif and other clusters as far north as Littrow crater. If indeed related, these smaller clusters could then form a large cluster, a constituent of a nearby ray of Tycho.][
]
Composition
Evidence from the Apollo 17 mission indicates that the massifs surrounding the valley are composed primarily of feldspar-rich breccia and that basalt underlies the valley floor, a result of the lava flows during the valley's geologic history. Seismic
Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other ...
studies suggest that the basalt below the valley floor is greater than 1400 meters (4600 feet) thick. Above the layer of subfloor basalt lies a deposit of unconsolidated material of various compositions ranging from volcanic material to impact-formed regolith.[
The valley floor's unusually low ]albedo
Albedo (; ) is the measure of the diffuse reflection of solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body that refl ...
, or reflectivity, is a direct result of the volcanic material and glass beads located there. The deeper craters on the valley floor act as 'natural drill holes' and afforded Apollo 17 the ability to sample the subfloor basalt. These basalt samples are composed primarily of plagioclase
Plagioclase is a series of tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continuous solid solution series, more pro ...
, but also contain amounts of clinopyroxene
The pyroxenes (commonly abbreviated to ''Px'') are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents calcium (Ca), sodium (Na), iron (Fe I ...
and other minerals
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed ...
.[
The unconsolidated regolith layer on the valley floor has a thickness of about and contains ejecta from many impact event, most notably that which formed Tycho. Apollo 17 was thereby able to retrieve sample material from the Tycho impact without having to visit the crater itself. The possibility that select craters in the valley could be secondary impacts resulting from the Tycho impact presented further opportunity for sampling ejecta from that impact.][
There are several geologic deposits on the valley floor originating from a variety of events in the geologic timeline of the Moon. One of these formations, the light mantle, is a deposit of lightly colored material in a series of projections extending about six kilometres (3.7 mi) from the south massif across the floor. Pre-Apollo 17 analyses suggested that this deposit might have been the result of an avalanche originating from the northern slope of the south massif.][
Analysis of the mantle material collected during Apollo 17 revealed a finely-grained texture interspersed with larger fragments of rock. Evidence from these samples, together with visual observation during Apollo 17, indicate that the light mantle varies in thickness throughout the valley. Craters located farther away from the south massif penetrate through the light mantle to darker underlying material. Meanwhile, craters close to the south massif as wide as do not appear to penetrate to darker material at all. The age of the light mantle is estimated to be about the same as the valley's central crater cluster, or about 70–95 million years old.][
Apollo 17 discovered and returned ]Troctolite 76535
Troctolite 76535 is a lunar sample discovered and collected on the Apollo 17 mission in 1972 in the Taurus–Littrow valley. It has a mass of about and is about across at its widest point. It was collected by geologist astronaut Harrison Schmi ...
, a 4.25 billion-year-old coarse-grained
Granularity (also called graininess), the condition of existing in granules or grains, refers to the extent to which a material or system is composed of distinguishable pieces. It can either refer to the extent to which a larger entity is sub ...
troctolite
Troctolite (from Greek τρώκτης 'trout' and λίθος 'stone') is a mafic intrusive rock type. It consists essentially of major but variable amounts of olivine and calcic plagioclase along with minor pyroxene. It is an olivine-rich anorth ...
composed primarily of olivine
The mineral olivine () is a magnesium iron silicate with the chemical formula . It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers quickl ...
and plagioclase
Plagioclase is a series of tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continuous solid solution series, more pro ...
, in the valley as part of a rake sample. The sample has been called the most interesting to be returned from the Moon and has been the subject of thermochronological calculation in an effort to determine whether the Moon generated a core dynamo or formed a metallic core
Core or cores may refer to:
Science and technology
* Core (anatomy), everything except the appendages
* Core (manufacturing), used in casting and molding
* Core (optical fiber), the signal-carrying portion of an optical fiber
* Core, the centra ...
, an inquiry that has yielded results in apparent support of the former—an active, churning core which generated a magnetic field, manifested in the magnetism of the sample itself. Further analysis by Garrick-Bethell et al. of the sample reveals nearly unidirectional magnetism—perhaps parallel to that of a larger field—lending further support to the hypothesis that the sample's magnetic properties are the result of a core dynamo in lieu of a singular shock event acting upon it.
Rocks sampled in the immediate vicinity of the Lunar Module are mostly vesicular coarse-grained subfloor basalt, with some appearance of fine-grained basalt as well. Much of the valley floor, as indicated by observations of the immediate landing area, is made up of regolith and fragments varying in sizes excavated by several impacts in the Moon's history.
Landing site selection
As Apollo 17 was the final lunar mission of the Apollo program, planners identified a number of different scientific objectives in order to maximize the expedition's scientific productivity. Landing sites considered and rejected for previous missions received reconsideration. Taurus–Littrow was one of several potential landing sites considered for Apollo 17 along with Tycho crater, Copernicus
Nicolaus Copernicus (; pl, Mikołaj Kopernik; gml, Niklas Koppernigk, german: Nikolaus Kopernikus; 19 February 1473 – 24 May 1543) was a Renaissance polymath, active as a mathematician, astronomer, and Catholic canon, who formulated ...
crater, and Tsiolkovskiy crater on the far side, among others.[
Planners ultimately eliminated all but Taurus–Littrow from consideration for a combination of operational and scientific justifications. A landing at Tycho was thought to exceed mission safety constraints because of the rough terrain found there. A landing on the far side in Tsiolkovskiy would add the expense and logistical difficulty of communications satellites that would be necessary to maintain contact between the crew and mission control during surface operations, and data from Apollo 12 had already afforded an opportunity to gauge the timing and history of the Copernicus impact.][
Apollo mission planners ultimately selected Taurus–Littrow with the dual objectives of sampling ancient highland material and young volcanic material at the same landing site—the former in the form of Tycho ejecta, and the latter as a result the supposed volcanic origin of some of the valley floor's crater-like features.][
]
Future exploration
The Apollo 17 landing site within the valley is subject to NASA's guidelines for the protection of Apollo lunar landing sites issued in 2011, which recommend keeping new exploration away from the vicinity of the aging Apollo 17 hardware that NASA has identified as historically significant. Aerospace company PTScientists announced in 2019 that its ALINA lunar lander was planned to land 3 to 5 km (1.9 to 3.1 mi) away from the Apollo 17 LM within the Taurus–Littrow valley in early 2020, later postponed to an indefinite date no earlier the second half of 2021.
Craters within Taurus–Littrow
See also
* Apollo 17
*Geology of the Moon
The geology of the Moon (sometimes called selenology, although the latter term can refer more generally to " lunar science") is quite different from that of Earth. The Moon lacks a true atmosphere, which eliminates erosion due to weather. It does ...
*Mare Serenitatis
Mare Serenitatis (Latin ''serēnitātis'', the "Sea of Serenity") is a lunar mare located to the east of Mare Imbrium on the Moon. Its diameter is .
Geology
Mare Serenitatis is located within the Serenitatis basin, which is of the Nectarian epo ...
References
External links
Apollo 17 Preliminary Science Report
— Apollo 17 Professional Paper
LAC 43
— Lambert Conformal Projection map
Apollo Image Atlas
— Images of Taurus–Littrow
43D1S2(25) Apollo 17 Traverses
— Apollo 17 traverse map
— Catalog of samples from Taurus–Littrow
{{DEFAULTSORT:Taurus-Littrow (lunar valley)
Valleys on the Moon
Apollo program
Apollo 17