"was proposed to place an orbiter in Mars orbit by 2021 to study Phobos and Deimos through a series of close flybys. The mission is called Phobos And Deimos & Mars Environment (PADME). Two other Phobos missions that were proposed for the Discovery 13 selection included a mission called ""Merlin"", which would flyby Deimos but actually orbit and land on Phobos, and another one is ""Pandora"" which would orbit both Deimos and Phobos. The Japanese Aerospace Exploration Agency (JAXA) unveiled in 9 June 2015 the Martian Moons Exploration (MMX), a sample return mission targeting Phobos. MMX will land and collect"
"from the surface of Phobos -from a permanent outpost, to a transfer orbit. This sand could be released in front of the spacecraft during the descent maneuver and then resulting in a densification of the atmosphere just in front of the spacecraft. Phobos (moon) Phobos ( , , ; systematic designation: ) is the innermost and larger of the two natural satellites of Mars, the other being Deimos. Both moons were discovered in 1877 by American astronomer Asaph Hall. Phobos is a small, irregularly shaped object with a mean radius of and is seven times as massive as the outer"
"with the planet, or break up into a planetary ring. Phobos was discovered by astronomer Asaph Hall on 18 August 1877, at the United States Naval Observatory in Washington, D.C., at about 09:14 Greenwich Mean Time (contemporary sources, using the pre-1925 astronomical convention that began the day at noon, give the time of discovery as 17 August at 16:06 Washington mean time). Hall had discovered Deimos, Mars's other moon, a few days earlier on 12 August 1877 at about 07:48 UTC. The names, originally spelled ""Phobus"" and ""Deimus"" respectively, were suggested by Henry Madan (1838–1901), Science Master of Eton, based"
"Deimos (moon) Deimos (systematic designation: Mars II) is the smaller and outermost of the two natural satellites of the planet Mars, the other being Phobos. Deimos has a mean radius of and takes 30.3 hours to orbit Mars. Deimos is from Mars, much further than Mars's other moon, Phobos. It is named for Deimos who in Greek mythology is the twin brother of Phobos, and personifies terror. Deimos was discovered by Asaph Hall, III at the United States Naval Observatory in Washington, D.C. on 12 August 1877, at about 07:48 UTC (given in contemporary sources as ""11 August 14:40"" Washington"
"Deimos is only slightly brighter than Venus is from Earth. Just like Earth's Moon, both Phobos and Deimos are considerably fainter at non-full phases. Unlike Earth's Moon, Phobos's phases and angular diameter visibly change from hour to hour; Deimos is too small for its phases to be visible with the naked eye. Both Phobos and Deimos have low-inclination equatorial orbits and orbit fairly close to Mars. As a result, Phobos is not visible from latitudes north of 70.4°N or south of 70.4°S; Deimos is not visible from latitudes north of 82.7°N or south of 82.7°S. Observers at high latitudes (less"
"– rises as expected in the east but slowly. Despite the 30-hour orbit of Deimos, 2.7 days elapse between its rise and set for an equatorial observer, as it slowly falls behind the rotation of Mars. Because the orbit of Phobos is below synchronous altitude, the tidal forces from the planet Mars are gradually lowering its orbit. In about 50 million years, it could either crash into Mars's surface or break up into a ring structure around the planet. The origin of the two moons is not well understood. Their low albedo and carbonaceous chondrite composition have been regarded as"
"Phobos, and land once or twice and gather sand-like regolith particles using a simple pneumatic 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 Sample Return Capsule back to Earth, arriving in July 2029. The mission architecture uses three modules: propulsion module (1,800 kg), exploration module (150 kg) and the return module (1,050 kg). With the mass of Deimos and Phobos being too small to capture a satellite, it is not possible to orbit the Martian moons in"
"Center (DLR) and a study team with representatives of the scientific community and the space industry. The mission would explore the origin and the evolution of the two Martian moons, and would also contribute to the general questions of planetary formation and the workings of the Solar System. The origin of the Martian moons is controversial. Phobos and Deimos both have much in common with carbonaceous C-type asteroids, with spectra, albedo, and density 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. Another hypothesis is"
"could be released in front of the spacecraft during the descent maneuver and then resulting in a densification of the atmosphere just in front of the spacecraft. Deimos (moon) Deimos (systematic designation: Mars II) is the smaller and outermost of the two natural satellites of the planet Mars, the other being Phobos. Deimos has a mean radius of and takes 30.3 hours to orbit Mars. Deimos is from Mars, much further than Mars's other moon, Phobos. It is named for Deimos who in Greek mythology is the twin brother of Phobos, and personifies terror. Deimos was discovered by Asaph Hall,"
"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, as in the case of our own Moon. The origin of the Martian moons is still controversial. Phobos and Deimos both have much in common with carbonaceous C-type asteroids, with spectra, albedo, and density 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. Both moons have"
"it rises in the west and sets in the east, and does so twice per sol; Deimos on the other hand rises in the east and sets in the west, but orbits only a few hours slower than a Martian sol, so it spends about two and a half sols above the horizon at a time. The maximum brightness of Phobos at ""full moon"" is about magnitude −9 or −10, while for Deimos it is about −5. By comparison, the full Moon as seen from Earth is considerably brighter at magnitude −12.7. Phobos is still bright enough to cast shadows;"
"Mean Time, using an astronomical convention of beginning a day at noon, so 12 hours must be added to get the actual local mean time). Hall also discovered Phobos on 18 August 1877, at about 09:14 GMT, after deliberately searching for Martian moons. It is named after Deimos, a figure representing dread in Greek mythology. The names, at first spelled ""Phobus"" and ""Deimus"", were suggested by Henry Madan (1838–1901), Science Master of Eton, from Book XV of the ""Iliad"", where Ares (the Roman god Mars) summons Dread (Deimos) and Fear (Phobos). Deimos, like Mars's other moon, Phobos, has spectra, albedos,"
"crater on the Moon as well as Hall crater on the Martian moon Phobos are named in his honor. Asaph Hall Asaph Hall III (October 15, 1829 – November 22, 1907) was an American astronomer who is most famous for having discovered the moons of Mars, Deimos and Phobos, in 1877. He determined the orbits of satellites of other planets and of double stars, the rotation of Saturn, and the mass of Mars. Hall was born in Goshen, Connecticut, the son of Asaph Hall II (1800–42), a clockmaker, and Hannah Palmer (1804–80). His paternal grandfather Asaph Hall I (June 11,"
"a small amount that it rises every 5.5 days and takes 2.5 days between rising and setting for an equatorial observer. Thus Phobos crosses the Martian sky nearly 12 times in the time it takes Deimos to cross it just once. Phobos and Deimos can both eclipse the Sun as seen from Mars, although neither can completely cover its disk and so the event is in fact a transit, rather than an eclipse. For a detailed description of such events see the articles Transit of Phobos from Mars and Transit of Deimos from Mars. The Earth is visible from Mars"
"would see far side features that can never be seen from Earth. Since Earth is an inner planet, observers on Mars can occasionally view transits of Earth across the Sun. The next one will take place in 2084. They can also view transits of Mercury and transits of Venus. The moon Phobos appears about one third the angular diameter that the full Moon appears from Earth; on the other hand, Deimos appears more or less starlike with a disk barely discernible if at all. Phobos orbits so fast (with a period of just under one third of a sol) that"
"1877 by Asaph Hall; they are named after the characters Phobos (panic/fear) and Deimos (terror/dread), who, in Greek mythology, accompanied their father Ares, god of war, into battle. Mars was the Roman counterpart of Ares. In modern Greek, the planet retains its ancient name ""Ares"" (Aris: ""Άρης""). From the surface of Mars, the motions of Phobos and Deimos appear different from that of the Moon. Phobos rises in the west, sets in the east, and rises again in just 11 hours. Deimos, being only just outside synchronous orbit – where the orbital period would match the planet's period of rotation"
"Mars appears to be the angular diameter as seen from Earth (0.35°), and sends 40% of the light, approximately the brightness of a slightly cloudy afternoon on Earth. On June 3, 2014, the ""Curiosity"" rover on Mars observed the planet Mercury transiting the Sun, marking the first time a planetary transit has been observed from a celestial body besides Earth. Mars has two small moons: Phobos and Deimos. From the Martian surface, Phobos has one-third to one-half the angular diameter of the Sun while Deimos is barely more than a dot (only 2′ angular diameter). The orbital period of Phobos"
"these 'predictions', two craters on Deimos are named Swift and Voltaire, while on Phobos there is one named regio, ""Laputa Regio"", and one named planitia, ""Lagado Planitia"", both of which are named after places in ""Gulliver's Travels"" (the fictional Laputa, a flying island, and Lagado, imaginary capital of the fictional nation Balnibarbi). Many of the craters on Phobos are also named after characters in ""Gulliver's Travels"". Asaph Hall discovered Deimos on 12 August 1877 at about 07:48 UTC and Phobos on 18 August 1877, at the US Naval Observatory in Washington, D.C., at about 09:14 GMT (contemporary sources, using the"
"named after this mythological figure. The god’s Roman equivalent was Formido or Metus. Deimos was the son of Ares and Aphrodite. He is the twin brother of Phobos and nephew of the goddess Enyo who accompanied her brother Ares into battle, as well as his father's attendants, Trembling, Fear, Dread and Panic. Deimos is more of a personification and an abstraction of the sheer terror that is brought by war and he never appeared as an actual character in any story in Greek Mythology. His Roman equivalent was Formido or Metus. Asaph Hall, who discovered the moons of Mars, named"
"mainly phyllosilicates and other minerals known from Mars, point toward 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. Although the VNIR spectra of the moons of Mars resemble those of outer-belt asteroids, the thermal infrared spectra of Phobos are reported to be inconsistent with chondrites of any class. Mars may have moons smaller than in diameter, and a dust ring is predicted to exist between Phobos and Deimos. Dozens of crewless spacecraft, including orbiters, landers, and rovers, have been sent"
"than 70.4°) would see a noticeably smaller angular diameter for Phobos because they are farther away from it. Similarly, equatorial observers of Phobos would see a noticeably smaller angular diameter for Phobos when it is rising and setting, compared to when it is overhead. Observers on Mars can view transits of Phobos and transits of Deimos across the Sun. The transits of Phobos could also be called partial eclipses of the Sun by Phobos, since the angular diameter of Phobos is up to half the angular diameter of the Sun. However, in the case of Deimos the term ""transit"" is"
"orbit around it by a collision with a planetesimal. Overall, its exploration history is similar to those of Mars and of Phobos. Deimos has been photographed in close-up by several spacecraft whose primary mission has been to photograph Mars. No landings on Deimos have been made. The Soviet Phobos program sent two probes to Phobos. In case ""Phobos 1"" succeeded, ""Phobos 2"" could have been sent to Deimos. Both probes launched successfully in July 1988. The first was lost en route to Mars, whereas the second returned some data and images but failed shortly before beginning its detailed examination of"
"fade away as the trailing apex of Phobos is approached. They have been grouped into 12 or more families of varying age, presumably representing at least 12 Martian impact events. Nonetheless, in November 2018, astronomers concluded that the many grooves on Phobos were caused by boulders, ejected from the asteroid impact that created Stickney crater, that rolled around on the surface of the moon. Faint dust rings produced by Phobos and Deimos have long been predicted but attempts to observe these rings have, to date, failed. Recent images from ""Mars Global Surveyor"" indicate that Phobos is covered with a layer"
"the orbit should be very close to the planet. Hall Wrote “The chance of finding a satellite appeared to be very slight, so that I might have abandoned the search had it not been for the encouragement of my wife.” Asaph Hall discovered Deimos on 12 August 1877 at about 07:48 UTC and Phobos on 18 August 1877, at the US Naval Observatory in Washington, D.C., at about 09:14 GMT (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)."
"place occur more or less symmetrically before and after the winter solstice (however, the large eccentricity of Mars's orbit prevents true symmetry). Observers on Mars can also view lunar eclipses of Phobos and Deimos. Phobos spends about an hour in Mars's shadow; for Deimos it is about two hours. Surprisingly, despite its orbit being nearly in the plane of Mars's equator and despite its very close distance to Mars, there are some occasions when Phobos escapes being eclipsed. Phobos and Deimos both have synchronous rotation, which means that they have a ""far side"" that observers on the surface of Mars"
"Phobos and Deimos. These observations included a ""lunar"" (or rather phobian) eclipse as ""Spirit"" watched Phobos disappear into Mars' shadow. Some of ""Spirit""'s star gazing was designed to look for a predicted meteor shower caused by Halley's Comet, and although at least four imaged streaks were suspect meteors, they could not be unambiguously differentiated from those caused by cosmic rays. A transit of Mercury from Mars took place on January 12, 2005 from about 14:45 UTC to 23:05 UTC. Theoretically, this could have been observed by both ""Spirit"" and ""Opportunity""; however, camera resolution did not permit seeing Mercury's 6.1"" angular"
"for Deimos, except only zero or one transits occur during such an interval. It is easy to see that the shadow always falls on the ""winter hemisphere"", except when it crosses the equator during the vernal equinox and the autumnal equinox. Thus transits of Phobos and Deimos happen during Martian autumn and winter in the northern hemisphere and the southern hemisphere. Close to the equator they tend to happen around the autumnal equinox and the vernal equinox; farther from the equator they tend to happen closer to the winter solstice. In either case, the two intervals when transits can take"
"north of 70.4°N; for some days in the year, its shadow misses the surface entirely and falls north or south of Mars. At any given geographical location on the surface of Mars, there are two intervals in a Martian year when the shadow of Phobos or Deimos is passing through its latitude. During each such interval, about half a dozen transits of Phobos can be seen by observers at that geographical location (compared to zero or one transits of Deimos). Transits of Phobos happen during Martian autumn and winter in the respective hemisphere; close to the equator they happen around"
"orbit by 2021 and study Phobos and Deimos. It is called ""Phobos And Deimos & Mars Environment"" (PADME). Human exploration of Deimos could serve as a catalyst for the human exploration of Mars. Recently, it was proposed that the sands of Deimos or Phobos could serve as a valuable material for aerobraking in the colonization of Mars. Because the small delta-v budget of Phobos, a small amount of chemical fuel brought from Earth could be transformed in a very large amount of sand lifted from the surface of Phobos – from a permanent outpost, to a transfer orbit. This sand"
"of Cypselus on the shield of Agamemnon. American astronomer Asaph Hall named a satellite of the planet Mars, ""Phobos"", which he discovered along with the second Mars satellite, ""Deimos"", in 1877. Phobos is the larger of the two satellites. The word ""phobia"" derives from ""phobos"", (Φόβος), meaning fear. The two brothers Deimos and Phobos were particularly worshipped in the city state of ""Sparta"" as they were the sons of Ares, the god of war. Phobos in Greek literally means ""fear"" (). Spartan soldiers would idolize Phobos, because he symbolized discipline, and consistency of the armed forces. Because Phobos and Deimos"
"determine the distance of the Earth from the Sun, based upon the relative size of the orbits of Mars and the Earth. He noted that the edge of the disk of Mars appeared fuzzy because of its atmosphere, which limited the precision he could obtain for the planet's position. In August 1877, the American astronomer Asaph Hall discovered the two moons of Mars using a telescope at the U.S. Naval Observatory. The names of the two satellites, Phobos and Deimos, were chosen by Hall based upon a suggestion by Henry Madan, a science instructor at Eton College in England. During"
"as bright as Venus is from Earth; at the first- or third-quarter phase it would be about as bright as Vega. With a small telescope, a Martian observer could see Deimos's phases, which take 1.2648 days (Deimos's synodic period) to run their course. Unlike Phobos, which orbits so fast that it rises in the west and sets in the east, Deimos rises in the east and sets in the west. The Sun-synodic orbital period of Deimos of about 30.4 hours exceeds the Martian solar day (""sol"") of about 24.7 hours by such a small amount that 2.48 days (2.41 sols)"
"recovery on the surface. In 2007, the Canadian Space Agency funded a study by Optech and the Mars Institute for an unmanned mission to Phobos known as ""Phobos Reconnaissance and International Mars Exploration"" (PRIME). A proposed landing site for the PRIME spacecraft is at the ""Phobos monolith"", a prominent object near Stickney crater. The PRIME mission would be composed of an orbiter and lander, and each would carry 4 instruments designed to study various aspects of Phobos's geology. In 2008, NASA Glenn Research Center began studying a Phobos and Deimos sample return mission that would use solar electric propulsion. The"