Russia to Launch Probe of Mars Mystery Moon –Phobos

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On Wednesday Russia launches a probe for Mars that aims to collect samples of a Mars enigmatic moon, Phobos, and become Moscow's first successful planetary mission since the collapse of the Soviet Union. In a landmark space cooperation between Moscow and Beijing, the probe is also expected to deploy a Chinese satellite, Yinghuo-1, which will go into orbit around Mars and observe the planet itself.  The image above shows the proposed landing site of the Phobos-Grunt mission.


The Phobos-Grunt probe is to blast off from the Baikonur cosmodrome in Kazakhstan on a Zenit-2SB rocket at 00:16 am Moscow time (2016 GMT Tuesday), Russia's space agency Roscosmos said in a statement.

Russia hopes the mission will mark a triumphant return to interplanetary exploration, a field from which it has been entirely absent over the last decades even as US probes explored the farthest reaches of the solar system.

"If Phobos-Grunt fully carries out its mission, then this will be a world class achievement," said Igor Lisov, editor-in-chief of the specialist journal Novosti Kosmonavtiki (Space News). 

The voyage also comes as the world's space powers are showing renewed interest in the possibility of sending a man to Mars in the next decades, possibly in the 2030s.

Last week six men emerged from 520 days in isolation in Moscow after an unprecedented experiment that attempted to test the psychological and physiological effects of a return trip to Mars.

The main aim of the Phobos-Grunt mission is to bring back the first ever soil sample from Phobos, the larger of Mars' two moons. If all goes to plan, Phobos-Grunt should reach Mars in 2012 and then deploy its lander for Phobos in 2013 before returning the sample back to Earth in August 2014.

Phobos, which orbits Mars at a radius of just under 10,000 kilometres, is believed to be the closest moon to its planet anywhere in the solar system and scientists hope it will reveal secrets about the origins of the planets.

The probe is carrying numerous international experiments including a capsule of microbes prepared by the US Planetary Society to see if basic life forms can survive on a long mission in deep space.

Phobos-Grunt was to have been launched in 2009 but the date was put back until 2011, the soonest possible launch window when the planet's relative proximity to Earth makes a voyage feasible.

Earlier this year, ESA's Mars Express performed a special manouvre to observe an unusual alignment of Jupiter and Phobos. The impressive images have now been processed into a movie of this rare event. The origin of Phobos (which means "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 new development, scientists say they have uncovered firm evidence that Mars's largest moon, the mysterious 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's gravity.

An alternative theory suggests that Phobos could have been formed from the remnants of an earlier moon destroyed by Mars's 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.

Atlas_combi_410New 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 co-author 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.

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."

Russia's robotic mission to Phobos, named Phobos-Grunt (grunt means ground , or earth, in Russian) to be launched in 2011, will investigate the moon's composition in more detail.

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The Daily Galaxy via bbc.co.uk

Three frames from the series of 104 taken by Mars Express during the Phobos-Jupiter conjunction on 1 June 2011. Credits: ESA/DLR/FU Berlin (G. Neukum)

Digital terrain model of Phobos derived from HRSC data
Credit: M. Wählisch et al. (2009)

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