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A sample-return mission is a
spacecraft A spacecraft is a vehicle that is designed spaceflight, to fly and operate in outer space. Spacecraft are used for a variety of purposes, including Telecommunications, communications, Earth observation satellite, Earth observation, Weather s ...
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. To date, samples of
Moon rock 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 ...
from Earth's
Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...
have been collected by robotic and crewed missions; the comet Wild 2 and the asteroids 25143 Itokawa, 162173 Ryugu, and
101955 Bennu 101955 Bennu ( provisional designation ) is a carbonaceous asteroid in the Apollo group discovered by the LINEAR Project on 11 September 1999. It is a potentially hazardous object that is listed on the Sentry Risk Table and has the second hig ...
have been visited by robotic spacecraft which returned samples to Earth; and samples of the
solar wind The solar wind is a stream of charged particles released from the Sun's outermost atmospheric layer, the Stellar corona, corona. This Plasma (physics), plasma mostly consists of electrons, protons and alpha particles with kinetic energy betwee ...
have been returned by the robotic '' Genesis'' mission. In addition to sample-return missions, samples from three identified non-terrestrial bodies have been collected by other means: samples from the Moon in the form of Lunar meteorites, samples from
Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...
in the form of Martian meteorites, and samples from Vesta in the form of HED meteorites.


Scientific use

Samples available on Earth can be analyzed in
laboratories A laboratory (; ; colloquially lab) is a facility that provides controlled conditions in which science, scientific or technological research, experiments, and measurement may be performed. Laboratories are found in a variety of settings such as s ...
, so we can further our understanding and knowledge as part of the discovery and exploration of the Solar System. Until now, many important scientific discoveries about the
Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Sola ...
were made remotely with
telescope A telescope is a device used to observe distant objects by their emission, Absorption (electromagnetic radiation), absorption, or Reflection (physics), reflection of electromagnetic radiation. Originally, it was an optical instrument using len ...
s, and some Solar System bodies were visited by orbiting or even landing spacecraft with instruments capable of
remote sensing Remote sensing is the acquisition of information about an physical object, object or phenomenon without making physical contact with the object, in contrast to in situ or on-site observation. The term is applied especially to acquiring inform ...
or sample analysis. While such an investigation of the Solar System is technically easier than a sample-return mission, the scientific tools available on Earth to study such samples are far more advanced and diverse than those that can go on spacecraft. Further, analysis of samples on Earth allows follow up of any findings with different tools, including tools that can tell intrinsic extraterrestrial material from terrestrial contamination, and those that have yet to be developed; in contrast, a spacecraft can carry only a limited set of analytic tools, and these have to be chosen and built long before launch. Samples analyzed on Earth can be matched against findings of remote sensing for more insight into the processes that formed the Solar System. This was done, for example, with findings by the ''Dawn'' spacecraft, which visited the asteroid Vesta from 2011 to 2012 for imaging, and samples from HED meteorites (collected on Earth until then), which were compared to data gathered by Dawn. These meteorites could then be identified as material ejected from the large impact crater Rheasilvia on Vesta. This allowed deducing the composition of the crust, mantle and core of Vesta. Similarly, some differences in the composition of asteroids (and, to a lesser extent, different compositions of
comet A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or Coma (cometary), coma surrounding ...
s) can be discerned by imaging alone. However, for a more precise inventory of the material on these different bodies, more samples will be collected and returned in the future, to match their compositions with the data gathered through telescopes and
astronomical spectroscopy Astronomical spectroscopy is the study of astronomy using the techniques of spectroscopy to measure the electromagnetic spectrum, spectrum of electromagnetic radiation, including Visible light astronomy, visible light, Ultraviolet astronomy, ultr ...
. One further focus of such investigation—besides the basic composition and geologic history of the various Solar System bodies—is the presence of the building blocks of life on comets, asteroids,
Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...
or the moons of the
gas giant A gas giant is a giant planet composed mainly of hydrogen and helium. Jupiter and Saturn are the gas giants of the Solar System. The term "gas giant" was originally synonymous with "giant planet". However, in the 1990s, it became known that Uranu ...
s. Several sample-return missions to asteroids and comets are currently in the works. More samples from asteroids and comets will help determine whether life formed in space and was carried to Earth by meteorites. Another question under investigation is whether
extraterrestrial life Extraterrestrial life, or alien life (colloquially, aliens), is life that originates from another world rather than on Earth. No extraterrestrial life has yet been scientifically conclusively detected. Such life might range from simple forms ...
formed on other Solar System bodies like Mars or on the moons of the gas giants, and whether life might even exist there. The result of NASA's last "Decadal Survey" was to prioritize a Mars sample-return mission, as Mars has a special importance: it is comparatively "nearby", might have harbored life in the past, and might even continue to sustain life. Jupiter's moon Europa is another important focus in the search for life in the Solar System. However, due to the distance and other constraints, Europa might not be the target of a sample-return mission in the foreseeable future.


Planetary protection

Planetary protection aims to prevent biological contamination of both the target
celestial body An astronomical object, celestial object, stellar object or heavenly body is a naturally occurring physical entity, association, or structure that exists within the observable universe. In astronomy, the terms ''object'' and ''body'' are of ...
and the
Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...
in the case of sample-return missions. A sample return from Mars or other location with the potential to host life is a category V mission under COSPAR, which directs to the containment of any unsterilized sample returned to Earth. This is because it is unknown what the effects such hypothetical life would be on humans or the
biosphere The biosphere (), also called the ecosphere (), is the worldwide sum of all ecosystems. It can also be termed the zone of life on the Earth. The biosphere (which is technically a spherical shell) is virtually a closed system with regard to mat ...
of Earth.Joshua Lederberg
Parasites Face a Perpetual Dilemma
(PDF). Volume 65, Number 2, 1999 / ''American Society for Microbiology News'' 77.
For this reason,
Carl Sagan Carl Edward Sagan (; ; November 9, 1934December 20, 1996) was an American astronomer, planetary scientist and science communicator. His best known scientific contribution is his research on the possibility of extraterrestrial life, including e ...
and
Joshua Lederberg Joshua Lederberg (May 23, 1925 – February 2, 2008) was an American molecular biology, molecular biologist known for his work in microbial genetics, artificial intelligence, and the United States space program. He was 33 years old when he won t ...
argued in the 1970s that we should do sample-return missions classified as category V missions with extreme caution, and later studies by the NRC and ESF agreed.Preliminary Planning for an International Mars Sample Return Mission Report
of the International Mars Architecture for the Return of Samples (iMARS) Working Group 1 June 2008.
European Science Foundation – Mars Sample Return backward contamination – Strategic advice and requirements
July, 2012, – see Back Planetary Protection section. (for more details of the document se
abstract
.
Mars Sample Return: Issues and Recommendations
Task Group on Issues in Sample Return. National Academies Press, Washington, DC (1997).


Sample-return missions


First missions

In July 1969,
Apollo 11 Apollo 11 was a spaceflight conducted from July 16 to 24, 1969, by the United States and launched by NASA. It marked the first time that humans Moon landing, landed on the Moon. Commander Neil Armstrong and Lunar Module pilot Buzz Aldrin l ...
achieved the first successful sample return from another Solar System body when it returned of Lunar surface material. This was followed by of material and Surveyor 3 parts from Apollo 12, of material from
Apollo 14 Apollo 14 (January 31February 9, 1971) was the eighth crewed mission in the United States Apollo program, the third to Moon landing, land on the Moon, and the first to land in the Geology of the Moon#Highlands, lunar highlands. It was the las ...
, of material from
Apollo 15 Apollo 15 (July 26August 7, 1971) was the ninth crewed mission in the Apollo program and the fourth Moon landing. It was the first List of Apollo missions#Alphabetical mission types, J mission, with a longer stay on the Moon and a greate ...
, of material from
Apollo 16 Apollo 16 (April 1627, 1972) was the tenth human spaceflight, crewed mission in the United States Apollo program, Apollo space program, administered by NASA, and the fifth and penultimate to Moon landing, land on the Moon. It was the second o ...
, and of material from
Apollo 17 Apollo 17 (December 7–19, 1972) was the eleventh and final mission of NASA's Apollo program, the sixth and most recent time humans have set foot on the Moon. Commander Gene Cernan and Lunar Module Pilot Harrison Schmitt walked on the Moon, ...
. The
Apollo program The Apollo program, also known as Project Apollo, was the United States human spaceflight program led by NASA, which Moon landing, landed the first humans on the Moon in 1969. Apollo followed Project Mercury that put the first Americans in sp ...
as a whole returned over of lunar rocks and
regolith Regolith () is a blanket of unconsolidated, loose, heterogeneous superficial deposits covering solid rock. It includes dust, broken rocks, and other related materials and is present on Earth, the Moon, Mars, some asteroids, and other terrestria ...
, including
lunar soil Lunar regolith is the unconsolidated material found on the selenography, surface of the Moon and in the Lunar atmosphere, Moon's tenuous atmosphere. Sometimes referred to as Lunar soil, Lunar soil specifically refers to the component of regoli ...
, to the Lunar Receiving Laboratory in
Houston Houston ( ) is the List of cities in Texas by population, most populous city in the U.S. state of Texas and in the Southern United States. Located in Southeast Texas near Galveston Bay and the Gulf of Mexico, it is the county seat, seat of ...
. Orloff 2004
"Extravehicular Activity"
/ref> Today, 75% of the samples are stored at the Lunar Sample Laboratory Facility built in 1979. In 1970, the robotic
Soviet The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...
mission Luna 16 returned of lunar soil, followed by Luna 20's return of in 1974, and Luna 24's return of in 1976. Although they recovered far less than the Apollo missions, they did this fully automatically. Apart from these three successes, other attempts under the
Luna programme The Luna programme (from the Russian word "Moon, Luna" meaning "Moon"), occasionally called ''Lunik'' by western media, was a series of robotic spacecraft missions sent to the Moon by the Soviet Union between 1959 and 1976. The programme acc ...
failed. The first two missions were intended to compete with Apollo 11 and were undertaken shortly before it in June and July 1969. Luna E-8-5 No. 402 failed at start, and
Luna 15 Luna 15 was a robotic space mission of the Soviet Luna programme, that was in lunar orbit together with the Apollo 11 Command module ''Columbia''. On 21 July 1969, while Apollo 11 astronauts finished the first human moonwalk, Luna 15, a robotic ...
crashed on the Moon. Later, other sample-return missions failed: Kosmos 300 and Kosmos 305 in 1969, Luna E-8-5 No. 405 in 1970, Luna E-8-5M No. 412 in 1975 had unsuccessful launches, and Luna 18 in 1971 and
Luna 23 ''Luna 23'' was an uncrewed space mission of the Luna program developed by the Soviet Union. Overview ''Luna 23'' was a Soviet Moon lander mission which was intended to return a lunar sample to Earth. Launched to the Moon by a Proton-K/ D, t ...
in 1974 had unsuccessful landings on the Moon. In 1970, the Soviet Union planned for a 1975 first Mars sample-return mission in the Mars 5NM project. This mission was planned to use an N1 rocket, but this rocket never flew successfully and the mission evolved into the Mars 5M project, which would use a double launch with the smaller
Proton A proton is a stable subatomic particle, symbol , Hydron (chemistry), H+, or 1H+ with a positive electric charge of +1 ''e'' (elementary charge). Its mass is slightly less than the mass of a neutron and approximately times the mass of an e ...
rocket and an assembly at a
Salyut The ''Salyut'' programme (, , meaning "salute" or "fireworks") was the first space station programme, undertaken by the Soviet Union. It involved a series of four crewed scientific research space stations and two crewed military reconnaissa ...
space station. This Mars 5M mission was planned for 1979, but was canceled in 1977 due to technical problems and complexity.


1990s

The Orbital Debris Collection (ODC) experiment deployed on the Mir space station for 18 months in 1996–97 used
aerogel Aerogels are a class of manufacturing, synthetic porous ultralight material derived from a gel, in which the liquid component for the gel has been replaced with a gas, without significant collapse of the gel structure. The result is a solid wit ...
to capture particles from low Earth orbit, including both interplanetary dust and man-made particles.


2000s

The next mission to return extraterrestrial samples was the '' Genesis'' mission, which returned solar wind samples to Earth from beyond Earth orbit in 2004. Unfortunately, the ''Genesis'' capsule failed to open its parachute while re-entering the Earth's atmosphere and crash-landed in the Utah desert. There were fears of severe contamination or even total mission loss, but scientists managed to save many of the samples. They were the first to be collected from beyond lunar orbit. ''Genesis'' used a collector array made of wafers of ultra-pure
silicon Silicon is a chemical element; it has symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent metalloid (sometimes considered a non-metal) and semiconductor. It is a membe ...
,
gold Gold is a chemical element; it has chemical symbol Au (from Latin ) and atomic number 79. In its pure form, it is a brightness, bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal ...
,
sapphire Sapphire is a precious gemstone, a variety of the mineral corundum, consisting of aluminium oxide () with trace amounts of elements such as iron, titanium, cobalt, lead, chromium, vanadium, magnesium, boron, and silicon. The name ''sapphire ...
, and
diamond Diamond is a Allotropes of carbon, solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Diamond is tasteless, odourless, strong, brittle solid, colourless in pure form, a poor conductor of e ...
. Each different wafer was used to collect a different part of the
solar wind The solar wind is a stream of charged particles released from the Sun's outermost atmospheric layer, the Stellar corona, corona. This Plasma (physics), plasma mostly consists of electrons, protons and alpha particles with kinetic energy betwee ...
. ''Genesis'' was followed by
NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...
's '' Stardust'' spacecraft, which returned comet samples to Earth on 15 January 2006. It safely passed by Comet Wild 2 and collected dust samples from the comet's
coma A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to Nociception, respond normally to Pain, painful stimuli, light, or sound, lacks a normal Circadian rhythm, sleep-wake cycle and does not initiate ...
while imaging the comet's nucleus. ''Stardust'' used a collector array made of low-density aerogel (99% of which is space), which has about 1/1000 of the density of glass. This enables the collection of cometary particles without damaging them due to high impact velocities. Particle collisions with even slightly porous solid collectors would result in the destruction of those particles and damage to the collection apparatus. During the cruise, the array collected at least seven interstellar dust particles.


2010s and 2020s

In June 2010 the
Japan Aerospace Exploration Agency The is the Japanese national Aeronautics, air and space agency. Through the merger of three previously independent organizations, JAXA was formed on 1 October 2003. JAXA is responsible for research, technology development and launch of satell ...
(JAXA)
Hayabusa was a robotic spacecraft developed by the Japan Aerospace Exploration Agency (JAXA) to return a sample of material from a small near-Earth asteroid named 25143 Itokawa to Earth for further analysis. ''Hayabusa'', formerly known as MUSES-C ...
probe returned asteroid samples to Earth after a rendezvous with (and a landing on) S-type asteroid 25143 Itokawa. In November 2010, scientists at the agency confirmed that, despite failure of the sampling device, the probe retrieved micrograms of dust from the asteroid, the first brought back to Earth in pristine condition. The Russian
Fobos-Grunt Fobos-Grunt or Phobos-Grunt () was an attempted Russian sample return mission to Phobos (moon), Phobos, one of the moons of Mars. Fobos-Grunt also carried the Chinese Mars orbiter Yinghuo-1 and the tiny Living Interplanetary Flight Experiment f ...
was a failed sample-return mission designed to return samples from Phobos, one of the moons of Mars. It was launched on 8 November 2011, but failed to leave Earth orbit and crashed after several weeks into the southern Pacific Ocean. The
Japan Aerospace Exploration Agency The is the Japanese national Aeronautics, air and space agency. Through the merger of three previously independent organizations, JAXA was formed on 1 October 2003. JAXA is responsible for research, technology development and launch of satell ...
(JAXA) launched the improved '' Hayabusa2'' space probe on 3 December 2014. ''Hayabusa2'' arrived at the target near-Earth
C-type asteroid C-type (carbonaceous ) asteroids are the most common variety, forming around 75% of known asteroids. They are volatile-rich and distinguished by a very low albedo because their composition includes a large amount of carbon, in addition to rocks ...
162173 Ryugu (previously designated ) on 27 June 2018. It surveyed the asteroid for a year and a half and took samples. It left the asteroid in November 2019 and returned to Earth on 6 December 2020. The
OSIRIS-REx OSIRIS-REx was a NASA asteroid-study and sample-return mission that visited and collected samples from 101955 Bennu, a C-type asteroid, carbonaceous near-Earth object, near-Earth asteroid. The material, returned in September 2023, is expected ...
mission was launched in September 2016 on a mission to return samples from the asteroid
101955 Bennu 101955 Bennu ( provisional designation ) is a carbonaceous asteroid in the Apollo group discovered by the LINEAR Project on 11 September 1999. It is a potentially hazardous object that is listed on the Sentry Risk Table and has the second hig ...
. The samples are expected to enable scientists to learn more about the time before the birth of the Solar System, initial stages of planet formation, and the source of organic compounds that led to the formation of life. It reached the proximity of Bennu on 3 December 2018, where it began analyzing its surface for a target sample area over the next several months. It collected its sample on 20 October 2020, and landed back on Earth again on 24 September 2023, making OSIRIS-REx the fifth successful sample return mission for mankind, in its return of samples from an extra-terrestrial body. Shortly after the sample container was retrieved and transferred to an "airtight chamber at the
Johnson Space Center The Lyndon B. Johnson Space Center (JSC) is NASA's center for human spaceflight in Houston, Texas (originally named the Manned Spacecraft Center), where human spaceflight training, research, and flight controller, flight control are conducted. ...
in Houston, Texas", the lid on the container was opened. Scientists commented that they "found black dust and debris on the avionics deck of the OSIRIS-REx science canister" on the initial opening. Later study was planned. On 11 October 2023, the recovered capsule was opened to reveal a "first look" at the asteroid sample contents. On 13 December 2023, further studies of the returned sample were reported and revealed organic molecules as well as unknown materials which require more study to have a better idea of their composition and makeup. On 13 January 2024, NASA reported finally fully opening, after three months of trying, the recovered container with samples from the Bennu asteroid. The total weight of the recovered material weighed , over twice the mission's goal. China's CNSA launched the Chang'e 5 and 6 lunar sample-return mission on 23 November 2020 and 3 May 2024 respectively, which returned to Earth with 2 kilograms of lunar soil each on 16 December 2020 and 25 June 2024 respectively. These were the first lunar sample-return missions in over 40 years. The Chang'e 6 mission, which landed in the Apollo crater basin in the southern hemisphere of the lunar far side, was the first to retrieve samples from the
far side of the Moon The far side of the Moon is the hemisphere of the Moon that is facing away from Earth, the opposite hemisphere is the near side. It always has the same surface oriented away from Earth because of synchronous rotation in the Moon's orbit. C ...
, as all previous collective lunar samples having been collected from the near side.


Current missions

CNSA's
Tianwen-2 ''Tianwen-2'' () is a Chinese asteroid sample return and comet exploration mission that launched on 28 May 2025. China National Space Agency (CNSA) plans for the probe to return samples from asteroid 469219 Kamoʻoalewa in 2027. After the ...
was launched in May 2025 with the aim to return samples from 469219 Kamoʻoalewa which was launched in 2025.


Future missions

CNSA plans for a Mars sample return mission by 2030. Also, the Chinese Space Agency is designing a sample-retrieval mission from Ceres that would take place during the 2020s. JAXA is developing the MMX mission, a sample-return mission to Phobos that will be launched in 2026. MMX will study both
moons of Mars The two natural satellite, moons of Mars (planet), Mars are Phobos (moon), Phobos and Deimos (moon), Deimos. They are irregular in shape. Both were discovered by American astronomer Asaph Hall in August 1877 and are named after the Greek mytholo ...
, but the landing and the sample collection will be on Phobos. This selection was made because of the two moons, Phobos's orbit is closer to Mars and its surface may have particles blasted from Mars. Thus the sample may contain material originating on Mars itself. A propulsion module carrying the sample is expected to return to Earth in 2031. NASA and ESA have long planned a Mars Sample-Return Mission. The ''Perseverance'' rover, deployed in 2020, is collecting drill core samples and stashing them on the Mars surface. As of September 2023, it has gathered one atmospheric sample and 8 igneous rock samples, 11
sedimentary rock Sedimentary rocks are types of rock (geology), rock formed by the cementation (geology), cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or de ...
samples and a pair of regolith samples. On 22 November 2023, NASA announced that it was cutting back on the Mars sample-return mission due to a shortage of funds. In January 2024, the proposed NASA plan was challenged due to budget and scheduling considerations, and investigation into alternate plans begun. Russia has plans for
Luna-Glob Luna-Glob (, meaning ''Lunar sphere'') is a Moon exploration programme by Roscosmos meant to progress toward the creation of a fully robotic lunar base. When completed, the programme is intended to continue with crewed lunar missions, starting ...
missions to return samples from the Moon by 2027 and Mars-Grunt to return samples from Mars in the late 2020s.


Methods of sample return

Sample-return methods include, but are not restricted to the following:


Collector array

A collector array may be used to collect millions or billions of atoms, molecules, and fine particulates by using wafers made of different elements. The molecular structure of these wafers allows the collection of various sizes of particles. Collector arrays, such as those flown on ''Genesis'', are ultra-pure in order to ensure maximal collection efficiency, durability, and analytical distinguishability. Collector arrays are useful for collecting tiny, fast-moving atoms such as those expelled by the Sun through the solar wind, but can also be used for collection of larger particles such as those found in the coma of a comet. The NASA spacecraft known as ''Stardust'' implemented this technique. However, due to the high speeds and size of the particles that make up the coma and the area nearby, a dense solid-state collector array was not viable. As a result, another means for collecting samples had to be designed to preserve the safety of the spacecraft and the samples themselves.


Aerogel

Aerogel Aerogels are a class of manufacturing, synthetic porous ultralight material derived from a gel, in which the liquid component for the gel has been replaced with a gas, without significant collapse of the gel structure. The result is a solid wit ...
is a
silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant f ...
-based porous solid with a sponge-like structure, 99.8% of whose volume is empty space. Aerogel has about 1/1000 of the density of glass. An aerogel was used in the ''Stardust'' spacecraft because the dust particles the spacecraft was to collect would have an impact speed of about 6 km/s. A collision with a dense solid at that speed could alter their chemical composition or vaporize them completely. Since the aerogel is mostly transparent, and the particles leave a carrot-shaped path once they penetrate the surface, scientists can easily find and retrieve them. Since its pores are on the
nanometer 330px, Different lengths as in respect to the Molecule">molecular scale. The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm), or nanometer (American spelling Despite the va ...
scale, particles, even ones smaller than a grain of sand, do not merely pass through the aerogel completely. Instead, they slow to a stop and then are embedded within it. The ''Stardust'' spacecraft has a tennis-racket-shaped collector with aerogel fitted to it. The collector is retracted into its capsule for safe storage and delivery back to Earth. Aerogel is quite strong and easily survives both launching and space environments.


Robotic excavation and return

Some of the riskiest and most difficult types of sample-return missions are those that require landing on an extraterrestrial body such as an asteroid, moon, or planet. It takes a great deal of time, money, and technical ability to even initiate such plans. It is a difficult feat that requires that everything from launch to landing to retrieval and launch back to Earth is planned out with high precision and accuracy. This type of sample return, although having the most risks, is the most rewarding for
planetary science Planetary science (or more rarely, planetology) is the scientific study of planets (including Earth), celestial bodies (such as moons, asteroids, comets) and planetary systems (in particular those of the Solar System) and the processes of ...
. Furthermore, such missions carry a great deal of public outreach potential, which is an important attribute for
space exploration Space exploration is the process of utilizing astronomy and space technology to investigate outer space. While the exploration of space is currently carried out mainly by astronomers with telescopes, its physical exploration is conducted bo ...
when it comes to public support. The only successful robotic sample-return missions of this type have been Soviet
Luna Luna commonly refers to: * Earth's Moon, named "Luna" in Latin, Spanish and other languages * Luna (goddess) In Sabine and ancient Roman religion and myth, Luna is the divine embodiment of the Moon (Latin ''Lūna'' ). She is often presented as t ...
and Chinese
Chang'e Chang'e ( ; ), originally known as Heng'e (), is the goddess of the Moon and wife of Hou Yi, the great archer. Renowned for her beauty, Chang'e is also known for her ascending to the Moon with her pet Yu Tu, the Moon Rabbit and living in the Mo ...
lunar landers. While other missions collected materials from asteroids by various means, they did so without "landing", given their very low gravity.


List of missions


Crewed missions


Robotic missions


See also

*
Asteroid mining Asteroid mining is the hypothetical extractivism, extraction of materials from asteroids and other minor planets, including near-Earth objects. Notable asteroid mining challenges include the high cost of spaceflight, unreliable identification ...
*
Exploration of Mars The planet Mars has been explored remotely by spacecraft. Uncrewed spacecraft, Probes sent from Earth, beginning in the late 20th century, have yielded a large increase in knowledge about the Martian system, focused primarily on understanding G ...
*
Exploration of the Moon The physical exploration of the Moon began when ''Luna 2'', a space probe launched by the Soviet Union, made a deliberate impact on the surface of the Moon on 14 September, 1959. Prior to that the only available means of lunar exploration had ...
* Extraterrestrial sample curation * List of lunar probes * Robotic exploration of the Moon * Timeline of Solar System exploration


Notes


References


External links


The Lunar Sample Compendium
by NASA
Stardust Sample Catalog Database
by NASA
Genesis Solar Wind Samples Catalog
by NASA
Hayabusa Samples
by NASA

Jet Propulsion Laboratory Mars Exploration Program on sample return missions.
Stardust ''Homepage''
Jet Propulsion Laboratory ''Stardust'' mission website.
Genesis Mission ''Homepage''
Jet Propulsion Laboratory ''Genesis'' mission website.

''Stardust'' website on aerogel technology.

JAXA ''Hayabusa'' project update.
Evaluating the Biological Potential in Samples Returned from Planetary Satellites and Small Solar System Bodies
The National Academies, Space Science Board 1998 {{Portal bar, Astronomy, Space, Spaceflight, Technology Discovery and exploration of the Solar System Space hazards Spaceflight Spaceflight timelines