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.
Moon rocks on Earth come from four sources: those collected by six United States Apollo program crewed lunar landings from 1969 to 1972; those collected by three Soviet uncrewed Luna probes in the 1970s; those collected by the Chinese Lunar Exploration Program's uncrewed probes; and rocks that were ejected naturally from the lunar surface before falling to Earth as lunar meteorites.
Six Apollo missions collected 2,200 samples of material weighing 381 kilograms (840 lb), [1] processed into more than 110,000 individually cataloged samples. [2]
| Mission | Site | Sample mass returned [1] | Year |
|---|---|---|---|
| Apollo 11 | Mare Tranquillitatis | 21.55 kg (47.51 lb) | 1969 |
| Apollo 12 | Ocean of Storms | 34.30 kg (75.62 lb) | 1969 |
| Apollo 14 | Fra Mauro formation | 42.80 kg (94.35 lb) | 1971 |
| Apollo 15 | Hadley–Apennine | 76.70 kg (169.10 lb) | 1971 |
| Apollo 16 | Descartes Highlands | 95.20 kg (209.89 lb) | 1972 |
| Apollo 17 | Taurus–Littrow | 110.40 kg (243.40 lb) | 1972 |
Three Luna spacecraft returned with 301 grams (10.6 oz) of samples. [3] [4] [5]
| Mission | Site | Sample mass returned | Year |
|---|---|---|---|
| Luna 16 | Mare Fecunditatis | 101 g (3.6 oz) [6] | 1970 |
| Luna 20 | Mare Fecunditatis | 30 g (1.1 oz) [7] | 1972 |
| Luna 24 | Mare Crisium | 170 g (6.0 oz) [8] | 1976 |
The Soviet Union abandoned its attempts at a crewed lunar program in the 1970s, but succeeded in landing three robotic Luna spacecraft with the capability to collect and return small samples to Earth. A combined total of less than half a kilogram of material was returned.
In 1993, three small rock fragments from Luna 16, weighing 200 mg, were sold for US$ 442,500 at Sotheby's (equivalent to $933,317in 2023). [9] In 2018, the same three Luna 16 rock fragments sold for US$ 855,000 at Sotheby's. [10]
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| Mission | Site | Sample mass returned | Year |
|---|---|---|---|
| Chang'e 5 | Mons Rümker | 1,731 g (3.8 lb) [11] | 2020 |
| Chang'e 6 | Southern Apollo crater | 1,935.3 g (4.3 lb) [12] [13] | 2024 |
In 2020, Chang'e 5, the fifth lunar exploration mission of the Chinese Lunar Exploration Program, returned approximately 1,731 g (61.1 oz) of rocks and dust from the Oceanus Procellarum, (the Ocean of Storms), the largest dark region on the Moon, visible on the western edge. [14] The Chang'e-5 samples contain 'perplexing combination' of minerals and include the sixth new lunar mineral, named Changesite-(Y). This phosphate mineral characterized by colorless, transparent columnar crystals. [14] Researchers estimated the peak pressure (11-40 GPa) and impact duration (0.1-1.0 second) of the collision that shaped the sample. Using shock wave models, they estimated the resulting crater to be between 3 and 32 kilometers wide, depending on the impact angle. [15]
The follow-up mission to Chang'e 5, Chang'e 6, reached the Moon on May 8, 2024, and entered lunar orbit for 20 days to find an appropriate landing site. [12] On 1 June 2024, the lander separated from the orbiter and landed on a mare unit at the southern part of the Apollo crater (36.1°S, 208.3°E). [16] The mission objective was to collect about 2 kg of material from the far side of the Moon and bring it back to Earth.
The Chang’e-6 probe withstood the high temperatures and collected the samples by drilling into the Moon's surface and scooping soil and rocks with a mechanical arm, according to a statement from the China National Space Administration (CNSA). The collected rock was crushed, melted and drawn into filaments about one third of the diameter of a human hair, then spun into thread and woven into cloth. "The lunar surface is rich in basalt and since we're building a lunar base in the future, we will most likely have to make basalt into fibers and use it as building materials," said engineer Zhou Changyi. [17]
The samples were placed in the ascent vehicle, which docked with the Chang'e 6 orbiter-return vehicle on June 6, 2024 [12] China's Chang'e 6 lunar probe, carrying the first lunar rocks ever collected from the far side of the Moon, landed in China's Inner Mongolia region on June 25, 2024.
More than 370 lunar meteorites have been collected on Earth, [18] representing more than 30 different meteorite finds (no falls), with a total mass of over 1,090 kilograms (2,400 lb). [19] Some were discovered by scientific teams (such as ANSMET) searching for meteorites in Antarctica, with most of the remainder discovered by collectors in the desert regions of northern Africa and Oman. A Moon rock known as "NWA 12691", which weighs 13.5 kilograms (30 lb), was found in the Sahara Desert at the Algerian and Mauritanian borders in January 2017, [20] and went on sale for $2.5 million in 2020. [21]
Rocks from the Moon have been measured by radiometric dating techniques. They range in age from about 3.16 billion years old for the basaltic samples derived from the lunar maria, up to about 4.44 billion years old for rocks derived from the highlands. [22] Based on the age-dating technique of "crater counting," the youngest basaltic eruptions are believed to have occurred about 1.2 billion years ago, [23] but scientists do not possess samples of these lavas. In contrast, the oldest ages of rocks from the Earth are between 3.8 and 4.28 billion years.
| Mineral | Elements | Lunar rock appearance |
|---|---|---|
| Plagioclase feldspar | Calcium (Ca) Aluminium (Al) Silicon (Si) Oxygen (O) | White to transparent gray; usually as elongated grains. |
| Pyroxene | Iron (Fe), Magnesium (Mg) Calcium (Ca) Silicon (Si) Oxygen (O) | Maroon to black; the grains appear more elongated in the maria and more square in the highlands. |
| Olivine | Iron (Fe) Magnesium (Mg) Silicon (Si) Oxygen (O) | Greenish color; generally, it appears in a rounded shape. |
| Ilmenite | Iron (Fe), Titanium (Ti) Oxygen (O) | Black, elongated square crystals. |
Moon rocks fall into two main categories: those found in the lunar highlands (terrae), and those in the maria. The terrae consist dominantly of mafic plutonic rocks. Regolith breccias with similar protoliths are also common. Mare basalts come in three distinct series in direct relation to their titanium content: high-Ti basalts, low-Ti basalts, and Very Low-Ti (VLT) basalts.
Almost all lunar rocks are depleted in volatiles and are completely lacking in hydrated minerals common in Earth rocks. In some regards, lunar rocks are closely related to Earth's rocks in their isotopic composition of the element oxygen. The Apollo Moon rocks were collected using a variety of tools, including hammers, rakes, scoops, tongs, and core tubes. Most were photographed prior to collection to record the condition in which they were found. They were placed inside sample bags and then a Special Environmental Sample Container for return to the Earth to protect them from contamination. In contrast to the Earth, large portions of the lunar crust appear to be composed of rocks with high concentrations of the mineral anorthite. The mare basalts have relatively high iron values. Furthermore, some of the mare basalts have very high levels of titanium (in the form of ilmenite). [25]
| Plagioclase | Pyroxene | Olivine | Ilmenite | |
|---|---|---|---|---|
| Anorthosite | 90% | 5% | 5% | 0% |
| Norite | 60% | 35% | 5% | 0% |
| Troctolite | 60% | 5% | 35% | 0% |
Primary igneous rocks in the lunar highlands compose three distinct groups: the ferroan anorthosite suite, the magnesian suite, and the alkali suite.
Lunar breccias, formed largely by the immense basin-forming impacts, are dominantly composed of highland lithologies because most mare basalts post-date basin formation (and largely fill these impact basins).
| Plagioclase | Pyroxene | Olivine | Ilmenite | |
|---|---|---|---|---|
| High titanium content | 30% | 54% | 3% | 18% |
| Low titanium content | 30% | 60% | 5% | 5% |
| Very low titanium content | 35% | 55% | 8% | 2% |
Mare basalts are named as such because they frequently constitute large portions of the lunar maria. These typically contain 18–21 percent FeO by weight, and 1–13 percent TiO2. They are similar to terrestrial basalts, but have many important differences; for example, mare basalts show a large negative europium anomaly. The type location is Mare Crisium sampled by Luna 24.
The main repository for the Apollo Moon rocks is the Lunar Sample Laboratory Facility at the Lyndon B. Johnson Space Center in Houston, Texas. For safekeeping, there is also a smaller collection stored at White Sands Test Facility in Las Cruces, New Mexico. Most of the rocks are stored in nitrogen to keep them free of moisture. They are handled only indirectly, using special tools.
Some Moon rocks from the Apollo missions are displayed in museums, and a few allow visitors to touch them. One of these, called the Touch Rock, is displayed in the Smithsonian National Air and Space Museum in Washington, D.C. [28] The idea of having touchable Moon rocks at a museum was suggested by Apollo scientist Farouk El-Baz, who was inspired by his childhood pilgrimage to Mecca where he touched the Black Stone (which in Islam is believed to be sent down from the heavens). [29]
Moon rocks collected during the course of lunar exploration are currently considered priceless. [28] In 2002, a safe was stolen from the Lunar Sample Building that contained minute samples of lunar and Martian material. The samples were recovered, and NASA estimated their value during the ensuing court case at about $1 million for 10 oz (280 g) of material.[ citation needed ]
Naturally transported Moon rocks in the form of lunar meteorites are sold and traded among private collectors.[ citation needed ]
Apollo 17 astronauts Eugene Cernan and Harrison Schmitt picked up a rock "composed of many fragments, of many sizes, and many shapes, probably from all parts of the Moon". This rock was later labeled sample 70017. [30] President Nixon ordered that fragments of that rock should be distributed in 1973 to all 50 US states and 135 foreign heads of state. The fragments were presented encased in an acrylic sphere, mounted on a wood plaque which included the recipients' flag which had also flown aboard Apollo 17. [31] Many of the presentation Moon rocks are now unaccounted for, having been stolen or lost.
Three minerals were discovered from the Moon: armalcolite, tranquillityite, and pyroxferroite. Armalcolite was named for the three astronauts on the Apollo 11 mission: Armstrong, Aldrin and Collins.
Because of their rarity on Earth and the difficulty of obtaining more, Moon rocks have been frequent targets of theft and vandalism, and many have gone missing or were stolen.
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.
Luna 16 was an uncrewed 1970 space mission, part of the Soviet Luna program. It was the first robotic probe to land on the Moon and return a sample of lunar soil to Earth. The 101 grams sample was returned from Mare Fecunditatis. It represented the first successful lunar sample return mission by the Soviet Union and was the third lunar sample return mission overall.
Luna 20 was the second of three successful Soviet lunar sample return missions. It was flown as part of the Luna program as a robotic competitor to the six successful Apollo lunar sample return missions.
Anorthite (an = not, ortho = straight) is the calcium endmember of the plagioclase feldspar mineral series. The chemical formula of pure anorthite is CaAl2Si2O8. Anorthite is found in mafic igneous rocks. Anorthite is rare on the Earth but abundant on the Moon.
Anorthosite is a phaneritic, intrusive igneous rock characterized by its composition: mostly plagioclase feldspar (90–100%), with a minimal mafic component (0–10%). Pyroxene, ilmenite, magnetite, and olivine are the mafic minerals most commonly present.
The far side of the Moon is the lunar hemisphere that always faces away from Earth, opposite to the near side, because of synchronous rotation in the Moon's orbit. Compared to the near side, the far side's terrain is rugged, with a multitude of impact craters and relatively few flat and dark lunar maria ("seas"), giving it an appearance closer to other barren places in the Solar System such as Mercury and Callisto. It has one of the largest craters in the Solar System, the South Pole–Aitken basin. The hemisphere has sometimes been called the "Dark side of the Moon", where "dark" means "unknown" instead of "lacking sunlight" – each location on the Moon experiences two weeks of sunlight while the opposite location experiences night.
The Genesis Rock is a sample of Moon rock retrieved by Apollo 15 astronauts James Irwin and David Scott in 1971 during the second lunar EVA, at Spur crater on Earth's Moon. With a mass of c. 270 grams, it is currently stored at the Lunar Sample Laboratory Facility in Houston, Texas.
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.
A sample-return mission is a spacecraft mission to collect and return samples from an extraterrestrial location to Earth for analysis. Sample-return missions may bring back merely atoms and molecules or a deposit of complex compounds such as loose material and rocks. These samples may be obtained in a number of ways, such as soil and rock excavation or a collector array used for capturing particles of solar wind or cometary debris. Nonetheless, concerns have been raised that the return of such samples to planet Earth may endanger Earth itself.
Lunar regolith is the unconsolidated material found on the surface of the Moon and in the Moon's tenuous atmosphere. Sometimes referred to as Lunar soil, Lunar soil specifically refers to the component of regolith smaller than 1 cm. It differs substantially in properties from terrestrial soil.
The Lunar Magma Ocean (LMO) is the layer of molten rock that is theorized to have been present on the surface of the Moon. The LMO was likely present on the Moon from the time of the Moon's formation to tens or hundreds of millions of years after that time. The LMO was a thermodynamic consequence of the Moon's relatively rapid formation in the aftermath of a giant impact between the proto-Earth and another planetary body. As the Moon accreted from the debris from the giant impact, gravitational potential energy was converted to thermal energy. Due to the rapid accretion of the Moon, thermal energy was trapped since it did not have sufficient time to thermally radiate away energy through the lunar surface. The subsequent thermochemical evolution of the LMO explains the Moon's largely anorthositic crust, europium anomaly, and KREEP material.
A lunar regolith simulant is a terrestrial material synthesized in order to approximate the chemical, mechanical, engineering, mineralogical, or particle-size distribution properties of lunar regolith. Lunar regolith simulants are used by researchers who wish to research the materials handling, excavation, transportation, and uses of lunar regolith. Samples of actual lunar regolith are too scarce, and too small, for such research, and have been contaminated by exposure to Earth's atmosphere.
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.
Lunar Sample 61016, better known as "Big Muley", is a lunar sample discovered and collected on the Apollo 16 mission in 1972 in the Descartes Highlands, on the rim of Plum crater, near Flag crater. It is the largest sample returned from the Moon as part of the Apollo program. The rock, an 11.7 kg (26 lb) breccia consisting mainly of shocked anorthosite attached to a fragment of troctolitic "melt rock", is named after Bill Muehlberger, the Apollo 16 field geology team leader.
Chang'e 5 was the fifth lunar exploration mission in the Chinese Lunar Exploration Program of CNSA, and China's first lunar sample-return mission. Like its predecessors, the spacecraft is named after the Chinese moon goddess, Chang'e. It launched at 20:30 UTC on 23 November 2020, from Wenchang Spacecraft Launch Site on Hainan Island, landed on the Moon on 1 December 2020, collected ~1,731 g (61.1 oz) of lunar samples, and returned to the Earth at 17:59 UTC on 16 December 2020.
Allan Hills A81005 or ALH A81005 was the first meteorite to be recognised as a lunar meteorite. The meteorite Yamato 791197 was discovered in 1979 but its lunar origin was not recognised until 1984. ALH A81005 was found in 1982 in the Allan Hills at the end of the Transantarctic Mountains, during a meteorite gathering expedition (ANSMET).
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.
Ferroan anorthosite (FAN) is a pristine coarse-grained igneous rock found in the lunar highlands. FANs have a Ca-rich plagioclase composition greater than 90 wt%, with many consisting of an anorthite-content of 99 wt%. The first hand sample of FAN, Sample 15415, was discovered at the Apollo 15 landing site, Hadley-Apennine. FANs were also found at the Apollo 16 landing site, the Descartes Highlands. FANs have been used to give insights into the evolution of the early lunar crust. Wood et al. 1970 first proposed that FANs were the result of the flotation of plagioclase crystals in a lunar magma ocean (LMO). However, Wetherill 1975 suggested that FANs formed due to serial magmatism.
Serial magmatism is a model that requires basaltic magma to erupt and intrude repeatedly into a pre-existing crust. Regarding the Moon, the magma would have been partially melted in the lunar mantle due to heat produced by initial accretion, radioactive elements, and mantle overturn. As the intruded magma cools it differentiates by density, causing heavier materials to sink down into the lunar mantle, and lighter materials to rise to the crust. As each of the materials separate, they create diapirs which then sink or float to their respective positions. As each diapir solidifies, it would constitute that they would all have their own ages and geochemical signature that may allude to when each intrusion formed. This process would cover a primary lunar crust, and leave us with a complex crust where diapirs overlap and may be difficult to unravel.
The drill was deployed and penetrated to a depth of 35 cm before encountering hard rock or large fragments of rock. The column of regolith in the drill tube was then transferred to the soil sample container... the hermetically sealed soil sample container, lifted off from the Moon carrying 101 grams of collected material
Luna 20 was launched from the lunar surface on 22 February 1972 carrying 30 grams of collected lunar samples in a sealed capsule
the mission successfully collected 170.1 grams of lunar samples and deposited them into a collection capsule
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