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The two moons of Mars are Phobos and
Deimos Deimos, a Greek word for ''dread'', may refer to: * Deimos (deity), one of the sons of Ares and Aphrodite in Greek mythology * Deimos (moon), the smaller and outermost of Mars' two natural satellites * Elecnor Deimos, a Spanish aerospace company * ...
. They are irregular in shape. Both were discovered by American astronomer Asaph Hall in August 1877 and are named after the
Greek mythological A major branch of classical mythology, Greek mythology is the body of myths originally told by the ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the origin and nature of the world, the lives and activities of d ...
twin characters Phobos (fear and panic) and
Deimos Deimos, a Greek word for ''dread'', may refer to: * Deimos (deity), one of the sons of Ares and Aphrodite in Greek mythology * Deimos (moon), the smaller and outermost of Mars' two natural satellites * Elecnor Deimos, a Spanish aerospace company * ...
(terror and dread) who accompanied their father
Ares Ares (; grc, Ἄρης, ''Árēs'' ) is the Greek god of war and courage. He is one of the Twelve Olympians, and the son of Zeus and Hera. The Greeks were ambivalent towards him. He embodies the physical valor necessary for success in war ...
into battle. Ares, god of war, was known to the
Romans Roman or Romans most often refers to: *Rome, the capital city of Italy * Ancient Rome, Roman civilization from 8th century BC to 5th century AD *Roman people, the people of ancient Rome *''Epistle to the Romans'', shortened to ''Romans'', a lette ...
as
Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin at ...
. Compared to the
Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's sur ...
's
Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...
, the moons Phobos and Deimos are small. Phobos has a diameter of 22.2 km (13.8 mi) and a mass of 1.08 kg, while Deimos measures 12.6 km (7.8 mi) across, with a mass of 2.0 kg. Phobos orbits closer to Mars, with a
semi-major axis In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the two most widely separated points of the perimeter. The semi-major axis (major semiaxis) is the lon ...
of and an orbital period of 7.66 hours; while Deimos orbits farther with a semi-major axis of and an orbital period of 30.35 hours.


History


Early speculation

Speculation about the existence of the moons of
Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin at ...
had begun when the moons of
Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousand ...
were discovered. When
Galileo Galilei Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642) was an Italian astronomer, physicist and engineer, sometimes described as a polymath. Commonly referred to as Galileo, his name was pronounced (, ). He ...
, as a hidden report about his having observed two bumps on the sides of
Saturn Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius of about nine and a half times that of Earth. It has only one-eighth the average density of Earth; h ...
(later discovered to be its rings), used the anagram ''smaismrmilmepoetaleumibunenugttauiras'' for ''Altissimum planetam tergeminum observavi'' ("I have observed the most distant planet to have a triple form"),
Johannes Kepler Johannes Kepler (; ; 27 December 1571 – 15 November 1630) was a German astronomer, mathematician, astrologer, natural philosopher and writer on music. He is a key figure in the 17th-century Scientific Revolution, best known for his laws ...
had misinterpreted it to mean ''Salve umbistineum geminatum Martia proles'' (Hello, furious twins, sons of Mars). Perhaps inspired by Kepler (and quoting Kepler's third law of planetary motion),
Jonathan Swift Jonathan Swift (30 November 1667 – 19 October 1745) was an Anglo-Irish satirist, author, essayist, political pamphleteer (first for the Whigs, then for the Tories), poet, and Anglican cleric who became Dean of St Patrick's Cathedral, Du ...
's satire ''
Gulliver's Travels ''Gulliver's Travels'', or ''Travels into Several Remote Nations of the World. In Four Parts. By Lemuel Gulliver, First a Surgeon, and then a Captain of Several Ships'' is a 1726 prose satire by the Anglo-Irish writer and clergyman Jonathan ...
'' (1726) refers to two moons in Part 3, Chapter 3 (the "Voyage to
Laputa Laputa uh·poo·tuhis a flying island described in the 1726 book '' Gulliver's Travels'' by Jonathan Swift. It is about in diameter, with an adamantine base, which its inhabitants can manoeuvre in any direction using magnetic levitation. ...
"), in which Laputa's astronomers are described as having discovered two satellites of Mars orbiting at distances of 3 and 5 Martian diameters with periods of 10 and 21.5 hours. Phobos and Deimos (both found in 1877, more than a century after Swift's novel) have actual orbital distances of 1.4 and 3.5 Martian diameters, and their respective orbital periods are 7.66 and 30.35 hours. In the 20th century, V. G. Perminov, a spacecraft designer of early Soviet Mars and
Venus Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never f ...
spacecraft, speculated Swift found and deciphered records that Martians left on Earth. However, the view of most astronomers is that Swift was simply employing a common argument of the time, that as the inner planets Venus and Mercury had no satellites, Earth had one and Jupiter had four (known at the time), that Mars by analogy must have two. Furthermore, as they had not yet been discovered, it was reasoned that they must be small and close to Mars. This would lead Swift to making a roughly accurate estimate of their orbital distances and revolution periods. In addition Swift could have been helped in his calculations by his friend, the mathematician
John Arbuthnot John Arbuthnot FRS (''baptised'' 29 April 1667 – 27 February 1735), often known simply as Dr Arbuthnot, was a Scottish physician, satirist and polymath in London. He is best remembered for his contributions to mathematics, his members ...
.
Voltaire François-Marie Arouet (; 21 November 169430 May 1778) was a French Enlightenment writer, historian, and philosopher. Known by his '' nom de plume'' M. de Voltaire (; also ; ), he was famous for his wit, and his criticism of Christianity—e ...
's 1752 short story "
Micromégas ''Le Micromégas'' is a 1752 novella by the French philosopher and satirist Voltaire. Along with his story "Plato's Dream", it is an early example in the literary genre of science fiction and has its place in the development of the history of ...
", about an alien visitor to Earth, also refers to two moons of Mars. Voltaire was presumably influenced by Swift. In recognition of these 'predictions', two craters on Deimos are named
Swift Swift or SWIFT most commonly refers to: * SWIFT, an international organization facilitating transactions between banks ** SWIFT code * Swift (programming language) * Swift (bird), a family of birds It may also refer to: Organizations * SWIFT, ...
and
Voltaire François-Marie Arouet (; 21 November 169430 May 1778) was a French Enlightenment writer, historian, and philosopher. Known by his '' nom de plume'' M. de Voltaire (; also ; ), he was famous for his wit, and his criticism of Christianity—e ...
, while on Phobos there is one named regio, ''Laputa Regio'', and one named
planitia In geography, a plain is a flat expanse of land that generally does not change much in elevation, and is primarily treeless. Plains occur as lowlands along valleys or at the base of mountains, as coastal plains, and as plateaus or uplan ...
, ''Lagado Planitia'', both of which are named after places in ''Gulliver's Travels'' (the fictional
Laputa Laputa uh·poo·tuhis a flying island described in the 1726 book '' Gulliver's Travels'' by Jonathan Swift. It is about in diameter, with an adamantine base, which its inhabitants can manoeuvre in any direction using magnetic levitation. ...
, a flying island, and
Lagado Lagado is a fictional city from the 1726 satirical novel '' Gulliver's Travels'' by Jonathan Swift. Location Lagado is the capital of the nation Balnibarbi, which is ruled by a tyrannical king from a flying island called Laputa. Lagado is on the ...
, imaginary capital of the fictional nation Balnibarbi). Many of the craters on Phobos are also named after characters in ''Gulliver's Travels''.


Discovery

Asaph Hall discovered Deimos on August 12, 1877 at about 07:48 UTC and Phobos on August 18, 1877, at the
US Naval Observatory United States Naval Observatory (USNO) is a scientific and military facility that produces geopositioning, navigation and timekeeping data for the United States Navy and the United States Department of Defense. Established in 1830 as the Depo ...
(the
Old Naval Observatory The Old Naval Observatory is a historic site at 23rd and E Street in Northwest, Washington, D.C. It is where the United States Naval Observatory was located from 1844 to 1893, when it moved to its present grounds. The original observatory build ...
in Foggy Bottom) in Washington, D.C., at about 09:14
GMT Greenwich Mean Time (GMT) is the mean solar time at the Royal Observatory in Greenwich, London, counted from midnight. At different times in the past, it has been calculated in different ways, including being calculated from noon; as a cons ...
(contemporary sources, using the pre-1925 astronomical convention that began the day at noon, give the time of discovery as 11 August 14:40 and 17 August 16:06 Washington mean time respectively). At the time, he was deliberately searching for Martian moons. Hall had previously seen what appeared to be a Martian moon on 10 August, but due to bad weather, he could not definitively identify them until later. Hall recorded his discovery of Phobos in his notebook as follows: The telescope used for the discovery was the 26-inch (66 cm) refractor (telescope with a lens) then located at Foggy Bottom. In 1893 the lens was remounted and put in a new dome, where it remains into the 21st century. The names, originally spelled ''Phobus'' and ''Deimus'', respectively, were suggested by Henry Madan (1838–1901), Science Master of Eton, from Book XV of the ''
Iliad The ''Iliad'' (; grc, Ἰλιάς, Iliás, ; "a poem about Ilium") is one of two major ancient Greek epic poems attributed to Homer. It is one of the oldest extant works of literature still widely read by modern audiences. As with the ''Ody ...
'', where
Ares Ares (; grc, Ἄρης, ''Árēs'' ) is the Greek god of war and courage. He is one of the Twelve Olympians, and the son of Zeus and Hera. The Greeks were ambivalent towards him. He embodies the physical valor necessary for success in war ...
summons Fear and Fright. The granddaughter of Henry Madan's brother
Falconer Madan Falconer Madan (15 April 1851 – 22 May 1935) was Librarian of the Bodleian Library of Oxford University. Early life and education Falconer Madan was born in Cam, Gloucestershire, the fifth son of George and Harriet Madan. He was educated at ...
was Venetia Burney, who first suggested the name of the planet
Pluto Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of trans-Neptunian object, bodies beyond the orbit of Neptune. It is the ninth-largest and tenth-most-massive known object to directly orbit the S ...
.


Mars moon hoax

In 1959,
Walter Scott Houston Walter Scott Houston (May 30, 1912–December 23, 1993) was an American popularizer of amateur astronomy. He wrote the " Deep-Sky Wonders" column in '' Sky and Telescope'' magazine from 1946 to 1993. Biography Houston was born in Tippecanoe, ...
perpetrated a celebrated April Fool's hoax in the April edition of the ''Great Plains Observer'', claiming that "Dr. Arthur Hayall of the University of the Sierras reports that the moons of Mars are actually artificial satellites". Both Dr. Hayall and the University of the Sierras were fictitious. The hoax gained worldwide attention when Houston's claim was repeated in earnest by a Soviet scientist,
Iosif Shklovsky Iosif Samuilovich Shklovsky (russian: Ио́сиф Самуи́лович Шкло́вский; sometimes transliterated ''Josif, Josif, Shklovskii, Shklovskij'') (1 July 1916 – 3 March 1985) was a Soviet astronomer and astrophysicist. He ...
, who, based on a later-disproven density estimate, suggested Phobos was a hollow metal shell.


Recent surveys

Searches have been conducted for additional satellites. In 2003, Scott S. Sheppard and
David C. Jewitt David Clifford Jewitt (born 1958) is a British-American astronomer who studies the Solar System, especially its minor bodies. He is based at the University of California, Los Angeles, where he is a Member of the Institute for Geophysics and Pl ...
surveyed nearly the entire
Hill sphere The Hill sphere of an astronomical body is the region in which it dominates the attraction of satellites. To be retained by a planet, a moon must have an orbit that lies within the planet's Hill sphere. That moon would, in turn, have a Hill sph ...
of Mars for
irregular satellite In astronomy, an irregular moon, irregular satellite or irregular natural satellite is a natural satellite following a distant, inclined, and often eccentric and retrograde orbit. They have been captured by their parent planet, unlike regular s ...
s. However scattered light from Mars prevented them from searching the inner few arcminutes where the satellites Phobos and Deimos reside. No new satellites were found to an apparent limiting red magnitude of 23.5, which corresponds to radii of about 0.09 km using an albedo of 0.07.


Characteristics

If viewed from Mars's surface near its equator, full Phobos looks about one-third as big as a full moon on Earth. It has an
angular diameter The angular diameter, angular size, apparent diameter, or apparent size is an angular distance describing how large a sphere or circle appears from a given point of view. In the vision sciences, it is called the visual angle, and in optics, it ...
of between 8' (rising) and 12' (overhead). Due to its close orbit, it would look smaller when the observer is further away from the Martian equator and is below the horizon and thus not visible from Mars's polar ice caps. Deimos looks more like a bright star or planet for an observer on Mars, only slightly bigger than
Venus Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never f ...
looks from Earth; it has an angular diameter of about 2'. The Sun's angular diameter as seen from Mars, by contrast, is about 21'. Thus there are no total
solar eclipse A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby obscuring the view of the Sun from a small part of the Earth, totally or partially. Such an alignment occurs during an eclipse season, approximately every six mon ...
s on Mars, as the moons are far too small to completely cover the Sun. On the other hand, total
lunar eclipse A lunar eclipse occurs when the Moon moves into the Earth's shadow. Such alignment occurs during an eclipse season, approximately every six months, during the full moon phase, when the Moon's orbital plane is closest to the plane of the Ear ...
s of Phobos happen almost every night. The motions of Phobos and Deimos would appear very different from that of Earth's Moon. Speedy Phobos rises in the west, sets in the east, and rises again in just eleven hours, while Deimos, being only just outside
synchronous orbit A synchronous orbit is an orbit in which an orbiting body (usually a satellite) has a period equal to the average rotational period of the body being orbited (usually a planet), and in the same direction of rotation as that body. Simplified meanin ...
, rises as expected in the east but very slowly. Despite its 30-hour orbit, it takes 2.7 days to set in the west as it slowly falls behind the rotation of Mars. Both moons are tidally locked, always presenting the same face towards Mars. Since Phobos orbits Mars faster than the planet itself rotates, tidal forces are slowly but steadily decreasing its orbital radius. At some point in the future, when it falls within the Roche limit, Phobos will be broken up by these tidal forces and either crash into Mars or form a ring. Several strings of craters on the Martian surface, inclined further from the equator the older they are, suggest that there may have been other small moons that suffered the fate expected of Phobos, and that the Martian crust as a whole shifted between these events. Deimos, on the other hand, is far enough away that its orbit is being slowly boosted instead, akin to Earth's Moon.


Orbital details


Origin

The origin of the Martian moons is still controversial.Burns, J. A. "Contradictory Clues as to the Origin of the Martian Moons," in ''Mars'', H. H. Kieffer ''et al.,'' eds., U. Arizona Press, Tucson, 1992 Phobos and Deimos both have much in common with carbonaceous
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 ...
s, with spectra,
albedo Albedo (; ) is the measure of the diffuse reflection of solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body that refle ...
, and
density Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematicall ...
very similar to those of C- or D-type asteroids. Based on their similarity, one hypothesis is that both moons may be captured
main-belt asteroids The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies, of many sizes, but much smaller than planets, called ...
.Landis, G. A. "Origin of Martian Moons from Binary Asteroid Dissociation," American Association for the Advancement of Science Annual Meeting; Boston, MA, 2001
abstract
.
Both moons have very circular orbits which lie almost exactly in Mars's
equatorial plane The celestial equator is the great circle of the imaginary celestial sphere on the same plane as the equator of Earth. This plane of reference bases the equatorial coordinate system. In other words, the celestial equator is an abstract projecti ...
, and hence a capture origin requires a mechanism for circularizing the initially highly eccentric orbit, and adjusting its inclination into the equatorial plane, most probably by a combination of atmospheric drag and
tidal force The tidal force is a gravitational effect that stretches a body along the line towards the center of mass of another body due to a gradient (difference in strength) in gravitational field from the other body; it is responsible for diverse phenomen ...
s, although it is not clear that sufficient time is available for this to occur for Deimos. Capture also requires dissipation of energy. The current
atmosphere of Mars The atmosphere of Mars is the layer of gases surrounding Mars. It is primarily composed of carbon dioxide (95%), molecular nitrogen (2.8%), and argon (2%). It also contains trace levels of water vapor, oxygen, carbon monoxide, hydrogen, and no ...
is too thin to capture a Phobos-sized object by atmospheric braking. Geoffrey Landis has pointed out that the capture could have occurred if the original body was a
binary asteroid A binary asteroid is a system of two asteroids orbiting their common barycenter. The binary nature of 243 Ida was discovered when the Galileo spacecraft flew by the asteroid in 1993. Since then numerous binary asteroids and several triple a ...
that separated under tidal forces. Phobos could be a second-generation Solar System object that coalesced in orbit after Mars formed, rather than forming concurrently out of the same birth cloud as Mars. Another hypothesis is that Mars was once surrounded by many Phobos- and Deimos-sized bodies, perhaps ejected into orbit around it by a collision with a large
planetesimal Planetesimals are solid objects thought to exist in protoplanetary disks and debris disks. Per the Chamberlin–Moulton planetesimal hypothesis, they are believed to form out of cosmic dust grains. Believed to have formed in the Solar System ...
.Craddock, R. A.; (1994); ''The Origin of Phobos and Deimos'', Abstracts of the 25th Annual Lunar and Planetary Science Conference, held in Houston, TX, 14–18 March 1994, p. 293 The high porosity of the interior of Phobos (based on the density of 1.88 g/cm3, voids are estimated to comprise 25 to 35 percent of Phobos' volume) is inconsistent with an asteroidal origin. Observations of Phobos in the
thermal infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
suggest a composition containing mainly
phyllosilicates Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust. In mineralogy, silica (silicon dioxide, ) is usually consid ...
, which are well known from the surface of Mars. The spectra are distinct from those of all classes of
chondrite A chondrite is a stony (non-metallic) meteorite that has not been modified, by either melting or differentiation of the parent body. They are formed when various types of dust and small grains in the early Solar System accreted to form pr ...
meteorites, again pointing away from an asteroidal origin. Both sets of findings support an origin of Phobos from material ejected by an impact on Mars that reaccreted in Martian orbit, similar to the prevailing theory for the origin of Earth's moon. The moons of Mars may have started with a huge collision with a protoplanet one third the mass of Mars that formed a ring around Mars. The inner part of the ring formed a large moon. Gravitational interactions between this moon and the outer ring formed Phobos and Deimos. Later, the large moon crashed into Mars, but the two small moons remained in orbit. This theory agrees with the fine-grained surface of the moons and their high porosity. The outer disk would create fine-grained material. Simulations suggest the object colliding with Mars had to be within the size range of Ceres and Vesta because a larger impact would have created a more massive disc and moons that would have prevented the survival of tiny moons like Phobos and Deimos. Most recently, Amirhossein Bagheri and his colleagues from
ETH Zurich (colloquially) , former_name = eidgenössische polytechnische Schule , image = ETHZ.JPG , image_size = , established = , type = Public , budget = CHF 1.896 billion (2021) , rector = Günther Dissertori , president = Joël Mesot , a ...
and
US Naval Observatory United States Naval Observatory (USNO) is a scientific and military facility that produces geopositioning, navigation and timekeeping data for the United States Navy and the United States Department of Defense. Established in 1830 as the Depo ...
, proposed a new hypothesis on the origin of the moons. By analyzing the seismic and orbital data from Mars InSight Mission and other missions, they proposed that the moons are born from disruption of a common parent body around 1 to 2.7 Billion years ago. The common progenitor of Phobos and Deimos was most probably hit by another object and shattered to form Phobos and Deimos. But a recent paper suggest that it seems unlikely that Phobos and Deimos are split directly from a single ancestral moon. They use N-body simulations to show that the single ancestral moon scenario should result in an impact between the two moons, leading to a debris ring in 104 years.


Exploration


Past attempts and proposals

While many Martian probes provided images and other data about Phobos and Deimos, only few were dedicated to these satellites and intended to perform a flyby or landing on the surface. Two probes under the Soviet
Phobos program Phobos (Greek for "fear") most commonly refers to: * Phobos (moon), a moon of Mars * Phobos (mythology), the Greek god and personification of fear and panic Phobos may also refer to: Comics * Phobos (Marvel Comics) * Phobos (''W.I.T.C.H.''), a ...
were successfully launched in 1988, but neither conducted the intended jumping landings on Phobos and Deimos due to failures (although '' Phobos 2'' successfully photographed Phobos). The post-Soviet Russian ''
Fobos-Grunt Fobos-Grunt or Phobos-Grunt (russian: link=no, Фобос-Грунт, where ''грунт'' refers to the ''ground'' in the narrow geological meaning of any type of soil or rock exposed on the surface) was an attempted Russian sample return mis ...
'' probe was intended to be the first
sample return mission 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 lo ...
from Phobos, but a rocket failure left it stranded in Earth orbit in 2011. Efforts to reactivate the craft were unsuccessful, and it fell back to Earth in an uncontrolled
re-entry Atmospheric entry is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. There are two main types of atmospheric entry: ''uncontrolled entry'', such as the entr ...
on 15 January 2012, over the
Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the conti ...
, west of Chile. In 1997 and 1998, the Aladdin mission was selected as a finalist in the NASA Discovery Program. The plan was to visit both Phobos and Deimos, and launch projectiles at the satellites. The probe would collect the ejecta as it performed a slow flyby. These samples would be returned to Earth for study three years later. Ultimately, NASA rejected this proposal in favor of ''
MESSENGER ''MESSENGER'' was a NASA robotic space probe that orbited the planet Mercury between 2011 and 2015, studying Mercury's chemical composition, geology, and magnetic field. The name is a backronym for "Mercury Surface, Space Environment, Geochem ...
'', a probe to Mercury. In 2007, the
European Space Agency , owners = , headquarters = Paris, Île-de-France, France , coordinates = , spaceport = Guiana Space Centre , seal = File:ESA emblem seal.png , seal_size = 130px , image = Views in the Main Control Room (120 ...
and
EADS Astrium Astrium was an aerospace manufacturer subsidiary of the European Aeronautic Defence and Space Company (EADS) that provided civil and military space systems and services from 2006 to 2013. In 2012, Astrium had a turnover of €5.8 billion and 1 ...
proposed and developed a mission to Phobos in 2016 with a lander and sample return, but this mission was never flown.
Canadian Space Agency The Canadian Space Agency (CSA; french: Agence spatiale canadienne, ASC) is the national space agency of Canada, established in 1990 by the ''Canadian Space Agency Act''. The president is Lisa Campbell, who took the position on September 3, 202 ...
has been considering the Phobos Reconnaissance and International Mars Exploration (PRIME) mission to Phobos with orbiter and lander since 2007. Since 2013 NASA developed the Phobos Surveyor mission concept with an orbiter and a small rover. NASA's PADME mission was designed to conduct multiple flybys of the Martian moons, but was not chosen for development. Also, NASA is assessing the OSIRIS-REx II, concept mission for a sample return from Phobos. Another sample return mission from Deimos, called ''Gulliver'', has been conceptualized.


Current proposals

JAXA The is the Japanese national 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 satellites into o ...
plans to launch
Martian Moons eXploration (MMX) The Martian Moons eXploration (MMX) is a robotic space probe set for launch in 2024 to bring back the first samples from Mars' largest moon Phobos. Developed by the Japanese Aerospace Exploration Agency (JAXA) and announced on 9 June 2015, MM ...
mission in 2024 to bring back the first samples from Phobos.NASA confirms contribution to Japanese-led Mars mission
Stephen Clark, ''Spaceflight Now'' 20 November 2017
and land once or twice and gather sand-like regolith particles using a simple
pneumatic Pneumatics (from Greek ‘wind, breath’) is a branch of engineering that makes use of gas or pressurized air. Pneumatic systems used in industry are commonly powered by compressed air or compressed inert gases. A centrally located and ...
system. The lander mission aims to retrieve a minimum of samples. The spacecraft will then take off from Phobos and make several flybys of the smaller moon Deimos before sending the Return Module back to
Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's sur ...
, arriving in July 2029.


Gallery

Image:Phobos.jpg, Phobos, with Stickney Crater on the right (2003). Image:Phobosmgs.gif, Phobos (1998). Image:Phobos deimos diff.jpg, Comparison - Phobos (top) and
Deimos Deimos, a Greek word for ''dread'', may refer to: * Deimos (deity), one of the sons of Ares and Aphrodite in Greek mythology * Deimos (moon), the smaller and outermost of Mars' two natural satellites * Elecnor Deimos, a Spanish aerospace company * ...
(bottom) (2005).


See also

* * * Satellites of Mars * *


References


Further reading


First International Conference On The Exploration Of Phobos And Deimos (2007)

Pascal Lee – ''A Case for the Human Exploration of the Moons of Mars'' (2007)
(pdf)


External links


Gazetteer of Planetary Nomenclature – Mars (USGS)Interactive 3D visualisation of the orbits of Mars and its moons Phobos and Deimos
{{DEFAULTSORT:Moons Of Mars Lists of moons