The Fra Mauro formation (or Fra Mauro Highlands) is a formation on the near side of Earth's Moon that served as the landing site for the American Apollo 14 mission in 1971. It is named after the 80-kilometer-diameter crater Fra Mauro, 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 was originally scheduled to land in the Fra Mauro highlands, but was unable due to an in-flight technical failure. [1] [2] [3]
Fra Mauro is thought to have been formed from ejecta, or debris, from the impact which formed Mare Imbrium. During Apollo 14, the crew members sampled ejecta from Cone 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. [2] [4]
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 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. [2] The petrology of the formation, based on data obtained on Apollo 14, indicates a history of impact and ejection possibly spanning over approximately 500 million years. [5]
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. [2]
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. [4]
Analysis of Apollo 14 samples suggests that there are five major geologic constituents present in the immediate landing area: regolith breccias, fragmental breccias, igneous lithologies, granulitic lithologies, and impact-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 crater, about 25 million years old, and surrounding older terrain. [6]
During Apollo 14, astronauts Alan Shepard and Edgar Mitchell recovered ejecta material from the Cone crater impact, which is believed to have excavated Imbrium impact material from a possible depth of about 80 m (260 ft). Most of the samples returned from the Moon from Fra Mauro are classified as breccias from the vicinity of Cone crater. [7]
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 basalts. 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 100 m (330 ft). It is believed [7] 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. [7]
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, and jointing or fracturing. [7]
As Apollo 14 was an early Apollo 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 should the Apollo Service Module engine fail. [8] After Apollo 12 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. [1]
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. 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. [1]
Apollo 14 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 specific sites of scientific interest on the Moon for two-day stays with two lunar extravehicular activities.
Oceanus Procellarum is a vast lunar mare on the western edge of the near side of the Moon. It is the only one of the lunar maria to be called an "Oceanus" (ocean), due to its size: Oceanus Procellarum is the largest of the maria ("seas"), stretching more than 2,500 km (1,600 mi) across its north–south axis and covering roughly 4,000,000 km2 (1,500,000 sq mi), accounting for 10.5% of the total lunar surface area.
Mare Imbrium 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 collision of a proto-planet during the Late Heavy Bombardment. Basaltic lava later flooded the giant crater to form the flat volcanic plain seen today. The basin's age has been estimated using uranium–lead dating methods to approximately 3.9 billion years ago, and the diameter of the impactor has been estimated to be 250 ± 25 km. The Moon's maria have fewer features than other areas of the Moon because molten lava pooled in the craters and formed a relatively smooth surface. Mare Imbrium is not as flat as it would have originally been when it first formed as a result of later events that have altered its surface.
Mare Cognitum is a lunar mare located in a basin or large crater which sits in the second ring of Oceanus Procellarum. To the northwest of the mare is the Montes Riphaeus mountain range, part of the rim of the buried crater or basin containing the mare. Previously unnamed, the mare received its name in 1964 in reference to its selection as the target for the successful impact probe Ranger 7, the first American spacecraft to return closeup images of the Moon's surface.
The lunar geological timescale divides the history of Earth's Moon into five generally recognized periods: the Copernican, Eratosthenian, Imbrian, Nectarian, and Pre-Nectarian. The boundaries of this time scale are related to large impact events that have modified the lunar surface, changes in crater formation through time, and the size-frequency distribution of craters superposed on geological units. The absolute ages for these periods have been constrained by radiometric dating of samples obtained from the lunar surface. However, there is still much debate concerning the ages of certain key events, because correlating lunar regolith samples with geological units on the Moon is difficult, and most lunar radiometric ages have been highly affected by an intense history of bombardment.
Fra Mauro is the worn remnant of a walled lunar plain. It is part of the surrounding Fra Mauro formation, being located to the northeast of Mare Cognitum and southeast of Mare Insularum. Attached to the southern rim are the co-joined craters Bonpland and Parry, which intrude into the formation forming inward-bulging walls. The crater is named after Italian geographer Fra Mauro.
Abulfeda is a lunar impact crater located in the central highlands of the Moon. To the northeast is the crater Descartes, and to the south-southeast is Almanon. To the north is the crater Dollond. A chain of craters named the Catena Abulfeda runs between the southern rim of Abulfeda and the north rim of Almanon, then continues for a length of 210 kilometers across the Rupes Altai. The crater was named for 14th century Kurdish historian Ismael Abul-fida.
The geology of the Moon is quite different from that of Earth. The Moon lacks a true atmosphere, and the absence of free oxygen and water eliminates erosion due to weather. Instead, the surface is eroded much more slowly through the bombardment of the lunar surface by micrometeorites. It does not have any known form of plate tectonics, it has a lower gravity, and because of its small size, it cooled faster. In addition to impacts, the geomorphology of the lunar surface has been shaped by volcanism, which is now thought to have ended less than 50 million years ago. The Moon is a differentiated body, with a crust, mantle, and core.
Moon rock or lunar rock is rock originating from Earth's Moon. This includes lunar material collected during the course of human exploration of the Moon, and rock that has been ejected naturally from the Moon's surface and landed on Earth as meteorites.
The Cayley Formation is a discontinuous unit of plains-forming material on the Moon. It was first recognized in the central near side of the Moon in 1965, by the Astrogeology group of the United States Geological Survey. It was previously mapped as part of the Fra Mauro formation. During the Apollo era, the formation was mapped in many other parts of the Moon including the far side
Taurus–Littrow is a lunar valley located on the near side at the coordinates 20.0°N 31.0°E. It served as the landing site for the American Apollo 17 mission in December 1972, the last crewed mission to the Moon. The valley is located on the southeastern edge of Mare Serenitatis 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.
The Descartes Highlands is an area of lunar highlands located on the near side that served as the landing site of the American Apollo 16 mission in early 1972. The Descartes Highlands is located in the area surrounding Descartes crater, after which the feature received its name.
Hadley–Apennine is a region on the near side of Earth's Moon that served as the landing site for the American Apollo 15 mission, the fourth crewed landing on the Moon and the first of the "J-missions", in July 1971. The site is located on the eastern edge of Mare Imbrium on a lava plain known as Palus Putredinis. Hadley–Apennine is bordered by the Montes Apenninus, a mountain range, and Hadley Rille, a meandering channel, on the east and west, respectively.
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 believe to be small bits of rapidly-cooled molten rock ejected in a fire fountain. It is about 110 meters in diameter and up to 14 m (15 yd) deep.
Shorty Crater is about 14 m deep. Based on our investigations at the site and later examination of photographs, the impact that formed it penetrated, in order, regolith on the avalanche deposit, the avalanche deposit, regolith on a basalt flow, a basalt flow overlying and protecting the orange and black glass layers, the orange and black glass layers, regolith on a second basalt flow, and, finally, the upper portion of that second flow. Orange and black glass clods and basalt boulders are spread throughout the ejecta blanket surrounding Shorty.
North Ray crater is a small crater in the Descartes Highlands of the Moon visited by the astronauts of Apollo 16. The name of the crater was formally adopted by the IAU in 1973. It is the largest crater sampled by astronauts during the Apollo program.
Nansen-Apollo is a feature on Earth's Moon, a crater in Taurus-Littrow valley, at the base of the South Massif. Astronauts Eugene Cernan and Harrison Schmitt visited it in 1972, on the Apollo 17 mission. The astronauts referred to it simply as Nansen during the mission. Geology Station 2 of the mission was located at Nansen. Nansen is located in the 'light mantle' which is almost certainly an avalanche deposit from the South Massif.
Spur is a feature on Earth's Moon, a crater in the Hadley–Apennine region. Astronauts David Scott and James Irwin visited it in 1971, on the Apollo 15 mission, during EVA 2. Spur was designated Geology Station 7.
Lunar Sample 14321, better known as "Big Bertha", is a lunar sample containing an embedded Earth-origin meteorite collected on the 1971 Apollo 14 mission. It was found in the Fra Mauro region of the Moon. Big Bertha is the first discovered meteorite from Earth, and the embedded meteorite portion is the oldest known Earth rock. At 8.998 kg (19.84 lb), this breccia rock is the third largest Moon sample returned during the Apollo program, behind Big Muley and Great Scott.
Head crater is a small crater in Oceanus Procellarum on the Moon. The name of the crater was formally adopted by the IAU in 1973.
Cone crater is a small crater in the Fra Mauro highlands, north of Fra Mauro crater, on the Moon. The name of the crater was formally adopted by the IAU in 1973.
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