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 381kg (840lb), processed into more than 110,000 individually cataloged samples.[1]
| Mission | Site | Sample mass returned[2] | Year | |
|---|---|---|---|---|
| Apollo 11 | Mare Tranquillitatis | 47.51order=flipNaNorder=flip | 1969 | |
| Apollo 12 | Ocean of Storms | 75.62order=flipNaNorder=flip | 1969 | |
| Apollo 14 | Fra Mauro formation | 94.35order=flipNaNorder=flip | 1971 | |
| Apollo 15 | Hadley-Apennine | 169.1order=flipNaNorder=flip | 1971 | |
| Apollo 16 | Descartes Highlands | 209.89order=flipNaNorder=flip | 1972 | |
| Apollo 17 | Taurus-Littrow | 243.4order=flipNaNorder=flip | 1972 |
Three Luna spacecraft returned with 301g of samples.[3] [4] [5]
| Mission | Site | Sample mass returned | Year | |
|---|---|---|---|---|
| Luna 16 | Mare Fecunditatis | 101g[6] | 1970 | |
| Luna 20 | Mare Fecunditatis | 30g[7] | 1972 | |
| Luna 24 | Mare Crisium | 170g[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 .[9] In 2018, the same three Luna 16 rock fragments sold for US$ 855,000 at Sotheby's.[10]
See also: Changesite–(Y).
| Mission | Site | Sample mass returned | Year | |
|---|---|---|---|---|
| Chang'e 5 | Mons Rümker | 1731abbr=onNaNabbr=on[11] | 2020 | |
| Chang'e 6 | Southern Apollo crater | 1935.3abbr=onNaNabbr=on[12] [13] | 2024 |
In 2020, Chang'e 5, the fifth lunar exploration mission of the Chinese Lunar Exploration Program, returned approximately 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. 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 to 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. 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[18] China’s Chang’e-6 lunar probe, carrying the first lunar rocks ever collected from the far side of the Moon, landing in China’s Inner Mongolia region on June 25, 2024.
More than 370 lunar meteorites have been collected on Earth,[19] representing more than 30 different meteorite finds (no falls), with a total mass of over 1090kg (2,400lb).[20] 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, was found in the Sahara Desert at the Algerian and Mauritanian borders in January 2017,[21] and went on sale for $2.5 million in 2020.[22]
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.[23] Based on the age-dating technique of "crater counting," the youngest basaltic eruptions are believed to have occurred about 1.2 billion years ago,[24] 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.
See main article: Geology of the Moon.
| 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. |
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]
| Pyroxene | Olivine | Ilmenite | |||
|---|---|---|---|---|---|
| 90% | 5% | 5% | 0% | ||
| 60% | 35% | 5% | 0% | ||
| 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).
| 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. 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 10oz of material.
Naturally transported Moon rocks in the form of lunar meteorites are sold and traded among private collectors.
See main article: Lunar sample displays.
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.
See main article: Stolen and missing Moon rocks. 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.