thumb|[[Olivine basalt collected from the rim of Hadley Rille by the crew of Apollo 15]]

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 lunar meteorites.

Sources

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.

Apollo program

Six Apollo missions collected 2,200 samples of material weighing through the use of the Apollo Lunar Sample Return Container,

{| class="wikitable"

|-

!Mission

!Site

!Sample mass<br />returned

!Year

|-

|Apollo 11

|Mare Tranquillitatis

|align="right"|

|align="right"|1969

|-

|Apollo 12

|Ocean of Storms

|align="right"|

|align="right"|1969

|-

|Apollo 14

|Fra Mauro formation

|align="right"|

|align="right"|1971

|-

|Apollo 15

|Hadley–Apennine

|align="right"|

|align="right"|1971

|-

|Apollo 16

|Descartes Highlands

|align="right"|

|align="right"|1972

|-

|Apollo 17

|Taurus–Littrow

|align="right"|

|align="right"|1972

|}

Luna program

Three Luna spacecraft returned with a total of of samples.

{| class="wikitable floatright"

|-

!Mission

!Site

!Sample mass<br />returned

!Year

|-

|-

|Luna 16

|Mare Fecunditatis

|align="right"|

|align="right"|1970

|-

|Luna 20

|Mare Fecunditatis

|align="right"|

|align="right"|1972

|-

|Luna 24

|Mare Crisium

|align="right"|

|align="right"|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&nbsp;mg, were sold for US$ 442,500 at Sotheby's (). In 2018, the same three Luna 16 rock fragments sold for US$ 855,000 at Sotheby's ().

Chang'e missions

{| class="wikitable floatright"

|-

!Mission

!Site

!Sample mass<br />returned

!Year

|-

|Chang'e 5

|Mons Rümker

| align="right" |

| align="right" |2020

|-

|Chang'e 6

|Southern Apollo crater

| align="right" |

|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. 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.

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. The mission objective was to collect about 2&nbsp;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 samples were placed in the ascent vehicle, which docked with the Chang'e 6 orbiter-return vehicle on June 6, 2024 representing more than 30 different meteorite finds (no falls), with a total mass of over . 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, and went on sale for $2.5&nbsp;million in 2020.

Dating

Rocks from the Moon have been measured by radiometric dating techniques. They range in age from about 3.16&nbsp;billion years old for the basaltic samples derived from the lunar maria, up to about 4.44&nbsp;billion years old for rocks derived from the highlands. Based on the age-dating technique of "crater counting," the youngest basaltic eruptions are believed to have occurred about 1.2&nbsp;billion years ago, 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&nbsp;billion years.

Composition

{| class="wikitable floatright" style="width:300px; font-size:90%"

|+Common lunar minerals

Highlands rocks

thumb|200px|left|Processing facility in Lunar Sample Building at [[Lyndon B. Johnson Space Center|JSC]]

thumb|200px|left|Slice of Moon rock at the [[National Air and Space Museum in Washington, DC]]

{| class="wikitable floatright" style="font-size:90%"

|+ Mineral composition of Highland rocks

!&nbsp;

! style="background:#E3E3DF" | Plagioclase

! style="background:#E3E3DF" | Pyroxene

! style="background:#E3E3DF" | Olivine

! style="background:#E3E3DF" | Ilmenite

|-

| style="background:#F1F3F3" | Anorthosite || 90% || 5% || 5% || 0%

|-

| style="background:#F1F3F3" | Norite || 60% || 35% || 5% || 0%

|-

| style="background:#F1F3F3" | 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).

  • The ferroan anorthosite suite consists almost exclusively of the rock anorthosite (>90% calcic plagioclase) with less common anorthositic gabbro (70-80% calcic plagioclase, with minor pyroxene). The ferroan anorthosite suite is the most common group in the highlands, and is inferred to represent plagioclase flotation cumulates of the lunar magma ocean, with interstitial mafic phases formed from trapped interstitial melt or rafted upwards with the more abundant plagioclase framework. The plagioclase is extremely calcic by terrestrial standards, with molar anorthite contents of 94–96% (An94–96). This reflects the extreme depletion of the bulk Moon in alkalis (Na, K) as well as water and other volatile elements. In contrast, the mafic minerals in this suite have low Mg/Fe ratios that are inconsistent with calcic plagioclase compositions. Ferroan anorthosites have been dated using the internal isochron method at circa 4.4 Ga.
  • The magnesian suite (or "Mg-suite) consists of dunites (>90% olivine), troctolites (olivine-plagioclase), and gabbros (plagioclase-pyroxene) with relatively high Mg/Fe ratios in the mafic minerals and a range of plagioclase compositions that are still generally calcic (An86–93). These rocks represent later intrusions into the highlands crust (ferroan anorthosite) at round 4.3–4.1 Ga. An interesting aspect of this suite is that analysis of the trace element content of plagioclase and pyroxene requires equilibrium with a KREEP-rich magma, despite the refractory major element contents.
  • The alkali suite is so-called because of its high alkali content—for Moon rocks. The alkali suite consists of alkali anorthosites with relatively sodic plagioclase (An70–85), norites (plagioclase-orthopyroxene), and gabbronorites (plagioclase-clinopyroxene-orthopyroxene) with similar plagioclase compositions and mafic minerals more iron-rich than the magnesian suite. The trace element content of these minerals also indicates a KREEP-rich parent magma. The alkali suite spans an age range similar to the magnesian suite.
  • Lunar granites are relatively rare rocks that include diorites, monzodiorites, and granophyres. They consist of quartz, plagioclase, orthoclase or alkali feldspar, rare mafics (pyroxene), and rare zircon. The alkali feldspar may have unusual compositions unlike any terrestrial feldspar, and they are often Ba-rich. These rocks apparently form by the extreme fractional crystallization of magnesian suite or alkali suite magmas, although liquid immiscibility may also play a role. U-Pb date of zircons from these rocks and from lunar soils have ages of 4.1–4.4 Ga, more or less the same as the magnesian suite and alkali suite rocks. In the 1960s, NASA researcher John A. O'Keefe and others linked lunar granites with tektites found on Earth although many researchers refuted these claims. According to one study, a portion of lunar sample 12013 has a chemistry that closely resembles javanite tektites found on Earth.
  • Lunar breccias range from glassy vitrophyre melt rocks, to glass-rich breccia, to regolith breccias. The vitrophyres are dominantly glassy rocks that represent impact melt sheets that fill large impact structures. They contain few clasts of the target lithology, which is largely melted by the impact. Glassy breccias form from impact melt that exit the crater and entrain large volumes of crushed (but not melted) ejecta. It may contain abundant clasts that reflect the range of lithologies in the target region, sitting in a matrix of mineral fragments plus glass that welds it all together. Some of the clasts in these breccias are pieces of older breccias, documenting a repeated history of impact brecciation, cooling, and impact. Regolith breccias resemble the glassy breccias but have little or no glass (melt) to weld them together. As noted above, the basin-forming impacts responsible for these breccias pre-date almost all mare basalt volcanism, so clasts of mare basalt are very rare. When found, these clasts represent the earliest phase of mare basalt volcanism preserved.

Mare basalts

{| class="wikitable floatright" style="font-size:90%"

|+ Mineral composition of mare basalts These are commonly encountered around the Oceanus Procellarum, and are identified in remote sensing by their high (about 10 ppm) thorium contents. Most of incompatible elements in KREEP basalts are incorporated in the grains of the phosphate minerals apatite and merrillite.

Curation and availability

thumb|200px|left|[[Genesis Rock returned by the Apollo 15 mission]]

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. 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).

Moon rocks collected during the course of lunar exploration are currently considered priceless. 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. Many of the presentation Moon rocks are now unaccounted for, having been stolen or lost.

Discoveries

Four minerals were discovered from the Moon: armalcolite, tranquillityite, pyroxferroite, and Changesite-(Y). Armalcolite was named for the three astronauts on the Apollo 11 mission: Armstrong, Aldrin and Collins.

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.

<gallery>

File:MoonTouch.jpg|A visitor touching a lunar sample at the Kennedy Space Center Visitor Complex

File:NASA Lunar Sample 15555.jpg|NASA Lunar sample 15555 on display at Space Center Houston Lunar Samples Vault, at NASA's Johnson Space Center

File:NASA Lunar Sample 15498.jpg|NASA Lunar sample 15498 on display at Space Center Houston Lunar Samples Vault, at NASA's Johnson Space Center

File:NASA Lunar Sample 60015.jpg|NASA Lunar sample 60015 on display at Space Center Houston Lunar Samples Vault, at NASA's Johnson Space Center

File:NASA Lunar Sample 60016.jpg|NASA Lunar sample 60016 on display at Space Center Houston Lunar Samples Vault, at NASA's Johnson Space Center

File:NASA Lunar Sample Return Container.jpg|NASA Lunar Sample Return Container with Lunar soil on display at Space Center Houston Lunar Samples Vault, at NASA's Johnson Space Center

File:Lunar Ferroan Anorthosite (60025).jpg|Lunar Ferroan Anorthosite #60025 (Plagioclase Feldspar). Collected by Apollo 16 from the Lunar Highlands near Descartes Crater. This sample is currently on display at the National Museum of Natural History in Washington, DC

File:Lunar Sample Processing Facility NASA JSC DSCN0199.JPG|Samples in Lunar Sample Building at JSC

File:SaturnVcenterPieceOfMoon.JPG|Moon rock on display for visitors to touch at the Apollo/Saturn V Center

File:Moon sample case in National Museum of Natural History.jpg|Sample collection case, containing collection bags for use on the surface, at the National Museum of Natural History

File:Moon tongs in National Museum of Natural History.jpg|Tongs used to pick up Moon rocks

File:Moon Regolith in Moscow.JPG|A piece of regolith from Apollo 11 presented to the Soviet Union and exhibited in the Memorial Museum of Cosmonautics in Moscow.

File:Apollo 17, Goodwill Moon Rock, close-up.jpg|Apollo 17 "Goodwill Moonrock"

File:Mondgestein Apollo 17 02-RZ.jpg|Cut fragment of Apollo 17 sample 76015, an impact melt breccia

File:Lunar sample 15016 S71-45477.jpg|Sample 15016, the Seatbelt basalt

File:Lunar Sample 61016 - Big Muley.jpg|Apollo 16's sample 61016, better known as Big Muley, is the largest sample collected during the Apollo program

File:Big Bertha sample 14321.jpg|Big Bertha, collected on Apollo 14, is among the largest rock samples returned from the Moon (nearly 9 kilograms)

File:Moon rocks on display at the National Museum of China.jpg|Moon rocks on display at the National Museum of China

File:Apollo15moonrock.jpg|This Moon rock was collected during the Apollo 15 mission in 1971. Located at the Lyndon B. Johnson Presidential Library in Austin, Texas.

</gallery>

See also

  • Sample-return mission
  • Bench Crater meteorite
  • Geology of the Moon
  • Hadley Rille meteorite
  • Helium-3
  • List of Apollo lunar sample displays
  • List of individual rocks
  • Lunar water
  • Lunar Receiving Laboratory
  • Lunar regolith simulant
  • Lunar resources
  • Lunar regolith
  • Portal 2

References

Citations

General sources

  • Paul D. Spudis, The Once and Future Moon, Smithsonian Institution Press, 1996, .
  • Rocks & Soils from the Moon—Johnson Space Center
  • Apollo Geology Tool Catalog
  • Lunar meteorites —Washington University, Department of Earth and Planetary Sciences
  • Lunar Samples Lunar and Planetary Institute
  • Articles about Moon rocks in Planetary Science Research Discoveries educational journal
  • Where Today are the Apollo 11 Lunar Sample Displays? collectSPACE
  • Where Today are the Apollo 17 Goodwill Moon Rocks? collectSPACE
  • Kentucky's lunar sample displays in the Kentucky Historical Society objects catalog: Apollo 11, Apollo 17