Fra Mauro formation
The Fra Mauro formation covers large portions of the lunar surface around Mare Imbrium. It is thought to be composed of ejecta from the impact which formed that basin. Much of the ejecta blanket from the Imbrium impact is covered with debris from younger impacts and material churned up by possible moonquakes. The area features relatively low ridges and hills, between which exist undulating valleys. Debris found in the formation may have originated from deep beneath the original crust. Samples collected there could give insight into the geologic history of the Moon. The petrology of the formation 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. During Apollo 14, astronauts Alan Shepard and Edgar Mitchell recovered ejecta material from the Cone crater impact. This crater is believed to have excavated Imbrium impact material from a possible depth of about 3 miles. Most of the samples returned from the Moon from Fra Mauro are classified as breccias from the vicinity of Cone crater. Analysis suggests 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 composition were recovered in one or both of two major surface units within the landing site.
The aborted Apollo 13 mission was originally scheduled to land at Fra Mauro. Apollo 14 was initially scheduled to land in the Littrow region of Mare Serenitatis. After Apollo 13 failed to land due to an in-flight technical failure, mission planners decided to re-target Apollo 14 to Fra Mauro. They regarded Fra Mauro as more interesting scientifically than the Littrow site. As Apollo 14 was an early Apollo mission, consideration for landing sites was restricted to equatorial regions. This restriction enabled the Moon-bound spacecraft to remain on a free-return trajectory should the Apollo Service Module engine fail. Mission planners chose a landing site near the relatively freshly formed Cone crater. That crater served as a natural drill hole to allow astronauts to obtain Imbrium ejecta.
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. 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. Two explanations have been presented for this discrepancy. The first suggests most basalt lies below the depth of excavation of Cone crater. The second proposes a basalt flow beneath the landing area excavated by a nearby crater with a diameter of 3 miles. It is believed the former seems more likely since the basalts are similar to those recovered at Cone crater. Data from the mission has helped determine the approximate age of Mare Imbrium.
The Fra Mauro formation takes its name from an 80-kilometer-diameter crater located within it. This crater and the surrounding formation take their names from a 15th-century Italian monk and mapmaker of the same name. The formation serves as the landing site for the American Apollo 14 mission in 1971. An oblique view of Fra Mauro was taken from lunar orbit on the Apollo 12 mission. 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. Debris found in the formation may have originated from deep beneath the original crust.
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Common questions
What is the Fra Mauro formation and where is it located on the Moon?
The Fra Mauro formation covers large portions of the lunar surface around Mare Imbrium. It features relatively low ridges and hills with undulating valleys between them.
When did the Apollo 14 mission land at the Fra Mauro formation?
The American Apollo 14 mission landed at the Fra Mauro formation in 1971. Mission planners re-targeted this site after the aborted Apollo 13 mission to recover samples from the area.
Who named the Fra Mauro formation and what is its origin?
The Fra Mauro formation takes its name from an 80-kilometer-diameter crater within it. This crater and the surrounding formation are named after a 15th-century Italian monk and mapmaker of the same name.
How old is the impact that formed the Imbrium basin according to Fra Mauro samples?
Samples obtained during the Apollo 14 mission suggest that the impact which formed the Imbrium basin is no older than 4.25 billion years. Analysis indicates the landing site is not floored by volcanic rocks or basalts.
What specific geological materials were recovered from the Cone crater near the Fra Mauro landing site?
Most samples returned from the Moon from Fra Mauro are classified as breccias from the vicinity of Cone crater. Five major geologic constituents include regolith breccias, fragmental breccias, igneous lithologies, granulitic lithologies, and impact-melt lithologies.