Russia’s Obsession with Mars’ Mystery Moon –A New Mission to Phobos?

 

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Russia will send another sample mission to the Martian moon Phobos if the European Space Agency (ESA) decides not to include Russia in its ExoMars program, the head of Russia’s space agency said on Tuesday. The space agency also announced that cosmic radiation was the most likely cause of the failure of the Phobos-Grunt probe that crashed to Earth this month, and suggested that a low-quality imported component may have been vulnerable to the radiation.

Phobos-Grunt, Russia's most ambitious planetary mission in decades, was launched on November 9, but failed due to propulsion failure and crashed back to Earth on January 15.


"We are holding consultations with the ESA about Russia’s participation in the ExoMars project… If no deal is reached, we will repeat the attempt [to launch a Phobos mission],” Roscosmos chief Vladimir Popovkin said. During the ExoMars mission, ESA plans to send an orbital spacecraft, ExoMars Trace Gas Orbiter, to Mars in 2016 and a robot rover two years later.

The rover will be able to cover several km in search of possible past and present signs of life, take samples from the surface and dig to the depth of two meters (six feet). 

The ExoMars program was run jointly by NASA and ESA but the U.S. space agency later said it would cut its participation in the project and will not provide its Atlas carrier for the launch. Russia said it could provide a Proton rocket to launch a European-led Mars telecommunications orbiter and a set of European and Russian sensors in 2016 in exchange for full membership in the exploration project.

Detailed mapping of Phobos has been conducted by the European Space Agency's Mars Express (MEx) satellite, and this information was used to identify a suitable location to land in February 2013. After landing, a robotic arm was to pick up samples of the regolith, which will be analysed there and then, but a portion of it – about 200g – will be transferred to a canister for return to Earth.

The oddly-shaped Phobos has been studied extensively by passing satellites, it still holds many secrets – not just about itself, but also the planet below. It is one of two moons at Mars (the other being Deimos). It has an extremely low density, indicating it probably has many interior spaces.

The origin of Mars' moon, Phobos (fear in ancient Greek), is a mystery, but three theories are considered plausible. The first is that the moon is a captured asteroid; the second is that it formed in-situ as Mars formed below it, and the third is that Phobos formed later than Mars, from debris flung into martian orbit when a massive meteorite struck the Red Planet. A fourth, far more radical and controversial (although thoroughly intriguing) theory is one that has been kicking around for decades: that Phobos is a artificial object in Mars orbit -in short, a 1.5-mile-long, extremely ancient spacecraft.

In a recent development, scientists say they have uncovered firm evidence that Phobos is made from rocks blasted off the Martian surface in a catastrophic event, solving  a long-standing puzzle. It has been suggested that both Phobos and Deimos could be asteroids that formed in the main asteroid belt and were then "captured" by Mars' gravity.

An alternative theory suggests that Phobos could have been formed from the remnants of an earlier moon destroyed by Mars' gravitational forces. However, this moon might itself have originated from material thrown into orbit from the Martian surface.

Previous observations of Phobos at visible and near-infrared wavelengths have been interpreted to suggest the possible presence of carbonaceous chondrites, found in meteorites that have crashed to Earth. This carbon-rich, rocky material, left over from the formation of the Solar System, is thought to originate in asteroids from the so-called "main belt" between Mars and Jupiter.

Data from the European Space Agency's Mars Express spacecraft appears to make the asteroid capture scenario look less likely. Recent observations as thermal infrared wavelengths using the Planetary Fourier Spectrometer (PFS) instrument on Mars Express show a poor match between the rocks on Phobos and any class of chondritic meteorite known from Earth, which seems to support the "re-accretion" models for the formation of Phobos, in which rocks from the surface of the Red Planet are blasted into Martian orbit to later clump and form Phobos.

"We detected for the first time a type of mineral called phyllosilicates on the surface of Phobos, particularly in the areas northeast of Stickney, its largest impact crater," said Dr Marco Giuranna, from the Italian National Institute for Astrophysics in Rome.These phyllosilicate rocks are thought to form in the presence of water, and have been found previously on Mars.

"This is very intriguing as it implies the interaction of silicate materials with liquid water on the parent body prior to incorporation into Phobos," said Dr Giuranna. "Alternatively, phyllosilicates may have formed in situ, but this would mean that Phobos required sufficient internal heating to enable liquid water to remain stable."

Other observations from Phobos appear to match the types of minerals identified on the surface of Mars. Thus, the make-up of Phobos appears more closely related to Mars than to asteroids from the main belt, say the researchers. In addition, said Pascal Rosenblatt of the Royal Observatory of Belgium, "the asteroid capture scenarios also have difficulties in explaining the current near-circular and near-equatorial orbit of both Martian moons (Phobos and Deimos)".

The researchers also used Mars Express to obtain the most precise measurement yet of Phobos' density."This number is significantly lower than the density of meteoritic material associated with asteroids. It implies a sponge-like structure with voids making up 25%-45% in Phobos's interior," said Dr Rosenblatt. A highly porous asteroid would have probably not survived if captured by Mars.

Alternatively, such a highly porous structure on Phobos could have resulted from the re-accretion of rocky blocks in Mars' orbit.

In describing the internal geometric structure of this "moon" as revealed by MARSIS,  European Space Agency (ESA) sources emphasized that "several of these interior Phobos compartments also appear to still be holding some kind of atmosphere …." which has given birth to wild speculation that Phobos could prove to be an artificial satellite of some sort.

The source repeated this several times … raising all kinds of fascinating questions regarding "how" the radar could, in fact, determine this — that some of the vast "rooms" inside Phobos ("from a quarter to half-a-mile in diameter …") were "maintaining an internal pressure."

The Daily Galaxy via ESAfederalspace.ru bbc.co.uk and  csmonitor.com

 

 

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