Phobos is a small body with irregular shape.Phobos is one of the darkest objects in the solar system.It moves around Mars three times a day, with an average distance of 9378km from Mars.[1]
Phobos (English pronunciation: "FOH bus" Phobos), in the shape of a potato, circles around Mars three times a day, with an average distance of 9378km from Mars.It isMarsThe larger of the two satellites is also the one closer to Mars.The distance between Phobos and Mars is also the shortest among all the satellites in the solar system and their host stars, only 6000 kilometers from the surface of Mars.It is also one of the smallest satellites in the solar system,
Phobos is a small body with irregular shape.Moving around Mars, the orbit is about 9400km away from the center of Mars, that is, 6000km away from the surface of Mars.Phobos is closer to its parent star than the moons of other known planets.Phobos is in the solar systemreflectivityOne of the lowest celestial bodies, Phobos, has a hugeImpact crater, called Stickney Crater.Because its orbit is very close to Mars, Phobos rotates faster than Marsrotation。Therefore, from the surface of Mars, Phobos rises in the west, crosses the sky in 4 hours and 15 minutes or less, and sets in the east.Due to the short orbital period andTidal forceThe orbit radius of Phobos is gradually getting smaller, and eventually it will hit the surface of Mars, or break into a ring of Mars.
Phobos is an irregularly shaped celestial body, approximately 27 kilometers long, 22 kilometers wide and 18 kilometers high.It orbits Mars every 0.319 days at a distance of 9235.6~9518.8 kilometers from Mars, which is faster than the rotation speed of Mars. Therefore, if humans arrive at Mars, they can also see the 'moon' of Mars rising in the west and setting in the east. Phobos and Phobos are mostly believed to be captured asteroids, and some people believe that they originated outside the solar system, rather than fromAsteroid belt。
Phobos
From November to December 1971Mariner 9 Mars probeThe first pictures of Phobos and Phobos were taken.Phobos has an overall dimension of 26.6 km × 22.2 km × 18.6 km, and its shape is a bit like a potato (see figure).It orbits an average distance of about 6000 kilometers from Mars, and it takes 7 hours and 39 minutes to rotate.Due to its small size and weight, Phobos has a weak gravitational pull, which is only 1/1600 of the Earth.In addition, Phobos' orbit is slowly decaying (falling by 9 meters every 100 years), and it will hit Mars in another 40 million years.Phobos has always been the research object of scientists' attention. Understanding Phobos can enable us to obtain a lot of information about the early history of the solar system.Alexander Zakharov, the chief scientist of Russia's "Phobos Soils" program, said: "It may provide us with clues about the formation of Earth satellites and other planetary satellites, and at the same time, understand the impact of asteroid impacts on rocksterrestrial planetThe role of the aspect. "Phobos's longest axis always points to Mars, and one side always faces Mars, making it an ideal place to observe most of the surface of Mars.
At the end of the last century, the former Soviet Union/Russia had formulated and implemented two plans to study Phobos using autonomous probes. Unfortunately, due to the failure of the probes and launch vehicles, they were unsuccessful.The first plan began in the late 1970s. For technical and financial reasons, it is planned to build two spacecraft, one hovering 50 meters above Phobos for television photography and scientific experiments;The other performs the Phobos sampling return task.The two detectors were launched in 1988, so they are called the "Phobos - 88" plan.In addition to Phobos, the research objectives of the mission also include Mars, the sun and space[2]。
Stellar properties
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Track characteristics
Phobos
Phobos's orbit radius is smaller than the radius of synchronous orbit, so its speed is fast. It usually rises in the west and sets in the east twice a day. Because it is too close to the surface of Mars, Phobos is located below the horizon on Mars where the latitude is higher than 70.5 °.It is inferred that since its running orbit is smaller than that of synchronous operationTidal forceIt is constantly making its orbit smaller and smaller (recent statistics show that it is decreasing at the speed of 2 meters per century).Therefore, it is estimated that after about 40 million years, Phobos will either collide with Mars or decompose into a halo (which is similar to the effect of the reaction force of the moon's lift).
Stellar composition
Phobos andPhobosProbably likeC-type asteroidIt is also composed of carbon rich rocks.But they can't be made of pure rock, because their density is too low.They are probably composed of a mixture of rock and ice, and they all have deep crustal pits.
Former Soviet UnionPhobos 2 detected a weak but persistent gas escaping from Phobos.Unfortunately, Phobos 2 cannot work until it detects the composition of the gas,waterProbably the most likely component.
Surface topography
The most prominent topographic feature on Phobos is a big pit named Stickney, which is the name of Hall's wife mentioned earlier.LikeEnceladusOfCraterherschel (Herschel).Stickney must have once played a role in destroying Phobos. Now some large grooves and streaky veins on the surface of Phobos are most likely caused by the influence of Stickney.
Discovery detection
Phobos was created byAssaf Hall(Asaph Hall) discovered by“Mariner 9 ”The first photo was taken by“Pirate 1”And Phobos in 1988.
Future significance
Phobos and Phobos may one day become very important "space stations" to understand Mars.Especially with the fact that ice exists, it has become a transit station for studying Mars.
Star anecdotes
PhobosdensityIt is very low. Some people believe that it is hollow, and even some people believe that it is actually a "Martian spaceship".Phobos's escape speed is very low, only one thousandth of that of the earth. If a professional jumper on the earth can stand on the surface of Phobos, he can“launch”Go into space.
Correlation analysis
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Aldrin explains the colony of Mars: you can control Phobos first
Simulate Mars Colony
According to foreign media reports“Apollo 11”Astronaut Edwin Aldrin believes that the Mars mission is not just a one-time space flight. Building a base on Mars will also face greater problems. But human beings must go to Mars and carry out the construction of colonies, which is the only chance for civilization to continue for a long time.John Grunsfeld, a former NASA astronaut, has previously proposed that species that only live on a single planet cannot survive forever. The extinction of dinosaurs is a typical example. Because this species has not developed intelligent technology, it can only be extinct in the event of celestial impact,
Mars is an ideal foothold for human beings, which can establish the firstSolar system planetscolony,University of PennsylvaniaDavid Dinges believes that humans after arriving at Mars need more space for activities, includinglifeSupport systems, daily necessities, etc., large space and sufficient support can reduce extreme psychological changes of astronauts.Since the Mars 500 project, six volunteers have spent 520 days living in an enclosed space of 3.6 meters by 20 meters, and have encountered common problems, such as insomnia and other disorders.
Therefore, in order to prevent astronauts from psychological problems in a narrow space, the Mars base will be a large living area for human beings, and construction and launch will face major problems. At least we have used almost all space forces to build an international space station.Aldrin believed that a base could be built on Phobos first, because the satellite has no atmospheric structure and does not need a large thermal shield device, and then the materials can be transported to the surface of Mars.At the same time, we will face the problem of food supply. We need to cultivate plant varieties that can resist radiation environment, low pressure and microgravity, and may even transform the soil transgenic project on Mars.NASAJet Propulsion LaboratoryRichard, the chief scientist ofInterplanetary spaceThe cost of flying is greatly reduced.
Mars may tear Phobos apart and eventually form a "ring of Mars"
Phobos surface parallel groove[6]
In November 2022, it was reported that the latest research by scientists showed that strange parallel grooves appeared on the surface of Phobos, which may be a sign that Mars is gradually tearing the moon apart.
NASA said that Phobos, trapped in the death spiral, is slowly approaching the surface of Mars at a speed of 1.8 meters every 100 years.Previously, the mysterious grooves on the surface of Phobos were thought to be caused by the impact of an asteroid in ancient times. The latest research shows that these grooves may be the result of Phobos getting closer to the surface of Mars and being slowly torn by the strong gravity of Mars, which is the so-called tidal force.
Scientists predict that as Phobos gets closer to the surface of Mars, the tidal force exerted on the surface of Phobos will increase until eventually the tidal force of Mars completely connects Phobos, when Phobos will completely tear apart, and debris may form a ring around Mars, just like Saturn's ring seen now.
At the current rate, Phobos will complete the death spiral and hit Mars in about 40 million years, but this schedule may also be advanced.[6]
Detection plan
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Phobos has been photographed recently by several spacecraft.The mission of these spacecraft is to image Mars, as early as 1971Mariner 9 Then came Viking 1 in 1977, Mars Global Surveyor in 1998 and 2003, Mars Express in 2004, 2008 and 2010, and Mars Reconnaissance Orbiter in 2007 and 2008.On August 25, 2005, the Spirit Mars rover obtained additional energy due to the wind blowing away the dust on the solar panel. Several night sky photos with short exposure time were taken from the surface of Mars, where Phobos and Phobos can be clearly seen.The special Phobos probes were the Soviet Forbes 1 and Forbes 2 launched in 1988.The former disappeared on the way to the fire, while the latter (including the lander) returned some data and images but failed shortly after starting the detailed survey of the satellite surface.Other Mars missions have collected more data, but the next special mission is the sampling and return mission launched in 2011,
The Russian Space Agency launched a return mission to Phobos in November 2011,Forbes - Soil, the return capsule also includes aPlanetary SocietyOflife sciencesExperiment - interplanetary flight life experiment LIFE.Other participants in this missionChina National Space AdministrationExploration spacecraft planned to enter Mars orbitYinghuo 1And the soil grinding and screening system of scientific loads on Phobos lander.However, after reaching Earth orbit, the Forbes Soil Probe failed to ignite and run to Earth.Since then, the rescue work has failed. In January 2012, Forbes Soil crashed on the earth,
It is reported that in 2007, European Space CorporationEADS AstriumA technical demonstration mission to Phobos is planned.Astrium is currently involvedEuropean Space AgencyA Mars sampling return mission of ESAAurora Programme Part of.Sending a spacecraft to Phobos with a small gravity field is a good way to test and verify the final Mars sampling and return mission.This mission is planned to start in 2016, and will last for three years. The company's aircraft will use an ion propelled "mother ship" to release a lander to the surface of Phobos.The lander will carry out some tests and experiments, collect samples into a cabin, then return to the mother ship, return to the earth, and the samples will be thrown to the ground, waiting for recovery,
In 2007,Canadian Space AgencyFundedOptechandMars Research InstituteThis is an unmanned exploration mission to Phobos, called PRIME (Phobos Reconnaissance and International Mars Exploration)
On July 23, 2022, the second anniversary of the launch of the Tianwen 1 mission, the orbiter sent back the image of Phobos.[5]
dispute
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The origin of Phobos is still controversial. Scientists believe that it may be an asteroid captured by the gravity of Mars.Phobos has abundant water under its surface, which is a valuable resource for space exploration and mining.[1]
world record
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Phobos's orbit is only 5981 kilometers away from Mars, and it is the closest satellite to the planet.(Guinness World Records)[3]
Related reports
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Phobos
On January 23, 2023, the Twitter account Amazing Astronomy shared a clear picture of Phobos, which shows the crater on the surface of the satellite.[7]
