The Fra Mauro formation (or Fra Mauro Highlands) is a
formation
Formation may refer to:
Linguistics
* Back-formation, the process of creating a new lexeme by removing or affixes
* Word formation, the creation of a new word by adding affixes
Mathematics and science
* Cave formation or speleothem, a secondar ...
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 ...
of
Earth's Moon that served as the landing site for the American
Apollo 14
Apollo 14 (January 31, 1971February 9, 1971) was the eighth crewed mission in the United States Apollo program, the third to land on the Moon, and the first to land in the lunar highlands. It was the last of the " H missions", landings at s ...
mission in 1971. It is named after the 80-kilometer-diameter crater
Fra Mauro
Fra Mauro, O.S.B. Cam., (c.1400–1464) was a Venetian cartographer who lived in the Republic of Venice. He created the most detailed and accurate map of the world up until that time, the Fra Mauro map.
Mauro was a monk of the Camaldolese ...
, located within it. The formation, as well as Fra Mauro crater, take their names from a
15th-century Italian monk and mapmaker of the same name.
Apollo 13
Apollo 13 (April 1117, 1970) was the seventh crewed mission in the Apollo space program and the third meant to land on the Moon. The craft was launched from Kennedy Space Center on April 11, 1970, but the lunar landing was aborted aft ...
was originally scheduled to land in the Fra Mauro highlands, but was unable due to an in-flight technical failure.
Fra Mauro is thought to have been formed from
ejecta
Ejecta (from the Latin: "things thrown out", singular ejectum) are particles ejected from an area. In volcanology, in particular, the term refers to particles including pyroclastic materials (tephra) that came out of a volcanic explosion and magma ...
, or debris, from the impact which formed
Mare Imbrium
Mare Imbrium (Latin ''imbrium'', the "Sea of Showers" or "Sea of Rains", "Sea of Tears") is a vast lava plain within the Imbrium Basin on the Moon and is one of the larger craters in the Solar System. The Imbrium Basin formed from the colli ...
. During Apollo 14, the crew members sampled ejecta from
Cone
A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the apex or vertex.
A cone is formed by a set of line segments, half-lines, or lines con ...
crater, a feature close in proximity to the immediate landing site of the mission, which provided insight into the composition of material deep inside the formation. Data from the mission has helped to determine the approximate age of Mare Imbrium, suggesting that it is no more than about 4.25 billion years old.
Formation and geography
Fra Mauro is a widespread hilly geological area covering large portions of the lunar surface around Mare Imbrium, and is thought to be composed of ejecta from the impact which formed Imbrium. The area is primarily composed of relatively low ridges and hills, between which exist undulating valleys. Much of the 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 ...
from the Imbrium impact is covered with debris from younger impacts and material churned up by possible moonquakes. Debris found in the formation may have originated from deep beneath the original crust, and samples collected there could give insight into the geologic history of the Moon.[ The ]petrology
Petrology () is the branch of geology that studies rocks and the conditions under which they form. Petrology has three subdivisions: igneous, metamorphic, and sedimentary petrology. Igneous and metamorphic petrology are commonly taught together ...
of the formation, based on data obtained on Apollo 14, indicates a history of impact and ejection possibly spanning over approximately 500 million years.
A relatively recent impact created Cone crater, 1,000 feet across and 250 feet deep, near the landing site of Apollo 14. One of the main objectives of that mission was to sample the original Imbrium material located on its rim.[
Samples obtained of the Fra Mauro formation during Apollo 14 suggest that the impact that formed the Imbrium basin is no older than 4.25 billion years.]
Geology
Analysis of Apollo 14 samples suggests that there are five major geologic constituents present in the immediate landing area: regolith
Regolith () is a blanket of unconsolidated, loose, heterogeneous superficial deposits covering solid rock. It includes dust, broken rocks, and other related materials and is present on Earth, the Moon, Mars, some asteroids, and other terrestria ...
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 di ...
s, fragmental breccias, igneous
Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or ...
lithologies
The lithology of a rock unit is a description of its physical characteristics visible at outcrop, in hand or core samples, or with low magnification microscopy. Physical characteristics include colour, texture, grain size, and composition. Lit ...
, granulitic lithologies, and impact
Impact may refer to:
* Impact (mechanics), a high force or shock (mechanics) over a short time period
* Impact, Texas, a town in Taylor County, Texas, US
Science and technology
* Impact crater, a meteor crater caused by an impact event
* Impac ...
- melt lithologies. Samples of each of these compositions were recovered in one or both of two major surface units of the Apollo 14 landing site within Fra Mauro: the immediate impact blanket of Cone
A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the apex or vertex.
A cone is formed by a set of line segments, half-lines, or lines con ...
crater, about 25 million years old, and surrounding older terrain.
During Apollo 14, astronauts Alan Shepard
Alan Bartlett Shepard Jr. (November 18, 1923 – July 21, 1998) was an American astronaut, naval aviator, test pilot, and businessman. In 1961, he became the second person and the first American to travel into space and, in 1971, he beca ...
and Edgar Mitchell
Edgar Dean Mitchell (September 17, 1930 – February 4, 2016) was a United States Navy officer and aviator, test pilot, aeronautical engineer, ufologist, and NASA astronaut. As the Lunar Module Pilot of Apollo 14 in 1971 he spent nine hour ...
recovered ejecta material from the Cone crater impact, which is believed to have excavated Imbrium impact material from a possible depth of about . Most of the samples returned from the Moon from Fra Mauro are classified as breccias from the vicinity of Cone crater.
Studies conducted upon samples from Apollo 14 have shown that the samples do not support the possibility that the landing site is floored by volcanic rocks, or basalt
Basalt (; ) is an aphanite, 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 planetary surface, surface of a terrestrial ...
s. Basalts are sparse in samples of Cone crater ejecta, but somewhat abundant in samples recovered farther west, on the opposite side of the immediate landing site. Two explanations have been presented for this: (1) the majority of basalt in the landing site lies below the depth of excavation of Cone crater or (2) the presence of a basalt flow beneath the landing area excavated by a nearby crater with a diameter of . It is believed that the former seems more likely, as the basalts are similar to the basalts recovered at Cone crater. It is inconclusive whether or not the recovered basalts have a direct affiliation with the landing site, as it is located in a valley between ridges, and there exists the possibility that the basalts were merely deposited there as a result of other impact events.
The Apollo 14 crew members sampled boulders in the ejecta of Cone crater. These boulders appeared to be layered and fractured breccias, contrasting from the appearance of the surrounding area because of their older age. As these boulders increase in size and number closer to Cone crater, it is believed that they originate from the greatest depth of excavation of Cone crater. These boulders show what is believed to be general characteristics of the Fra Mauro formation: clastic texture, stratification
Stratification may refer to:
Mathematics
* Stratification (mathematics), any consistent assignment of numbers to predicate symbols
* Data stratification in statistics
Earth sciences
* Stable and unstable stratification
* Stratification, or st ...
, and jointing or fracturing.
Landing site selection
As Apollo 14 was an early 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= ...
mission, consideration for landing sites was restricted to equatorial regions in order to enable the Moon-bound spacecraft to remain on a free-return trajectory
In orbital mechanics, a free-return trajectory is a trajectory of a spacecraft traveling away from a primary body (for example, the Earth) where gravity due to a secondary body (for example, the Moon) causes the spacecraft to return to the primar ...
should the Apollo Service Module
The Apollo command and service module (CSM) was one of two principal components of the United States Apollo spacecraft, used for the Apollo program, which landed astronauts on the Moon between 1969 and 1972. The CSM functioned as a mother ship ...
engine fail. After Apollo 12
Apollo 12 (November 14–24, 1969) was the sixth crewed flight in the United States Apollo program and the second to land on the Moon. It was launched on November 14, 1969, by NASA from the Kennedy Space Center, Florida. Commander Pete Conra ...
demonstrated the ability to land with some degree of precision at a pre-specified landing site, mission planners considered landings in rough, but geologically interesting areas of the Moon.[
The aborted Apollo 13 mission was originally scheduled to land at Fra Mauro, with Apollo 14 scheduled to land in the Littrow region 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 ep ...
. After Apollo 13 failed to land, mission planners decided to re-target Apollo 14 to Fra Mauro, as they regarded Fra Mauro as more interesting scientifically than the Littrow site. There, Apollo 14 had the objective of sampling ejecta from the Imbrium impact to gain insight into the Moon's geologic history. Mission planners chose a landing site near the relatively freshly formed Cone crater, as this crater served as a 'natural drill hole' to allow the astronauts to obtain Imbrium ejecta, a primary objective of the mission.[
]
References
External links
Area map
- Apollo 14 Professional Paper
{{DEFAULTSORT:Fra Mauro Formation
Geological features on the Moon
Apollo 13
Apollo 14