(ORDO NEWS) — The longstanding mystery about the origin of the Martian moons may be one step closer to solving.
The space probe moved tens of kilometers closer to the larger of the two satellite siblings to capture data on what lies beneath its cratered surface.
“Whether the two small moons of Mars are captured asteroids or are made of material torn from Mars during a collision is an open question,” says astronomer Colin Wilson of the European Space Agency (ESA). “Their appearance suggests they were asteroids, but the way they orbit Mars may suggest otherwise.”
Phobos, named after the ancient Greek deity of fear and panic, is the larger of the two moons and is 22.2 kilometers (13.8 miles) across and orbits Mars at an average distance from the surface of about 6,000 kilometers.
Deimos, named after the Greek god of terror and terror, is only 12.6 kilometers (7.8 miles) in diameter and at a much greater average orbital distance of about 20,000 kilometers from Mars.
They are both rather peculiar objects, in many respects unlike our satellite. There are also some interesting differences between them.
While Deimos is receding and may one day leave Mars entirely, Phobos is moving towards Mars in a decaying orbit that shrinks by 1.8 centimeters (0.7 inches) every year. , a journey in which it may rupture to form a ring within the next 100 million years or so.
It is also unclear where they came from. Plenty of compelling evidence points to our Moon breaking away from Earth in a giant impact, but Mars and its moons, millions of miles away, are not easy to study.
In terms of composition, Phobos and Deimos appear to be very similar, suggesting that they may have come from the same source; and this composition is also similar to a group of asteroids.
But they also have similar, neat orbits that are nearly circular and quite close to Mars’ equator, which is not typical of captured asteroids.
One way to find answers is to look under the hood, so to speak – to find out what lurks under the surface of the moons. So ESA sent its Mars Express orbiter to fly around Phobos, flying within 83 kilometers (about 51 miles) of the potato-like moon.
For context: the Karman line, which separates the Earth’s atmosphere from interplanetary space, passes at an altitude of about 100 kilometers. A span of only 83 km is close .
“We didn’t know if it was possible,” says ESA’s Mars Express flight controller Simon Wood. “The team tested several different software options, and the final successful settings were uploaded to the spacecraft just a few hours before the flyby.”
The flight itself took place towards the end of September. Purpose: To use an instrument called the Advanced Martian Subsurface and Ionosphere Sounding Radar (MARSIS) to explore beneath the surface of Phobos.
This is a radar instrument that sends low frequency radio waves to Mars; the way these waves bounce off various materials below the surface allows scientists to figure out what might be there.
This is how scientists suspect that there may be lakes of liquid water (or clay deposits, or volcanic rock). deposits or layers of rocks and ice) buried under the south polar ice cap of Mars. The instrument is now being tuned to demystify Phobos’ internal structure.
“We are still in the early stages of our analysis,” says astronomer Andrea Cicchetti of the National Institute of Astrophysics in Italy, which operates MARSIS.
“But we have already seen possible signs of previously unknown features below the lunar surface . We are excited to see the role that MARSIS can play in finally unraveling the mystery of the origin of Phobos.”
Over the next few years, Mars Express will fly even closer to the small, bumpy moon. The team hopes that from 2023 to 2025, the probe will approach the surface of Phobos at a distance of up to 40 kilometers. This will make it possible to collect even more data about its internal structure.
In addition, space agencies around the world are collaborating on missions to explore Martian satellites. This ambitious project aims to send a probe to Phobos and Deimos and study them in detail, as well as collect a sample from Phobos and bring it to Earth for detailed analysis.
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