Malfunctioning Russian probe spotted hurtling through space backward (+video)
Veteran satellite watcher Thierry Legault filmed the wayward Russian Phobos-Grunt probe, which was intended to collect soil samples from a Martian moon but is instead heading toward a destructive plunge back to earth.
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When will it fall?
Phobos-Grunt launched into space early Nov. 9 (Nov. 8 in the United States) and was intended to land on Phobos, one of two moons circling Mars. The spacecraft was designed to snare samples of Phobos' surface and rocket the specimens back to Earth in 2014.Skip to next paragraph
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But the Mars probe failed to boost itself out of Earth orbit on an interplanetary trajectory. Russian engineers have been unable to re-establish control of or contact with the spacecraft.
There is a convergence of tracking predictions that places Phobos-Grunt's uncontrolled fall into Earth's atmosphere in the Jan. 15-16 time period.
"That's about what we have as well … but there are uncertainties of several days still," said Holger Krag, deputy head of the European Space Agency's Space Debris Office, at the European Space Operations Center in Darmstadt, Germany.
As for media reports of the disabled spacecraft crashing into any specific place, Krag said, "This is, of course, nonsense. It can come down at any place."
Krag told SPACE.com that because our planet is covered by about 73 percent water, "there is a rather small chance that there would be a land impact."
That being the case, the message from Krag for ground-dwellers is clear-cut.
"Relax," Krag said. "The likelihood of somebody being hit is enormously low. It is way smaller than to be struck by lightning. If you have a thunderstorm above your city you would also not worry too much."
A massive falling spacecraft
When compared with last year's uncontrolled re-entry of NASA's defunct Upper Atmosphere Research Satellite on Sept. 24, followed by the downfall of Germany’s dead Roentgen Satellite (ROSAT) on Oct. 23, Russia's Phobos-Grunt is a special beast.
According to the Federal Space Agency (also known as Roscosmos), the Mars probe is filled with tons of hydrazine and nitrogen tetroxide. All that fuel is stored in the probe's propellant tanks, which are reportedly made of aluminum.
“It's heavy – more than 13 tons is what Roscosmos is reporting. But most of it is fuel. This is a major difference between UARS and ROSAT. They were Earth-bound spacecraft and they had their fuel more or less spent," Krag said. [6 Biggest Spacecraft to Fall Uncontrolled From Space]
It is not clear whether or not the huge quantity of fuel onboard the marooned Mars craft is in frozen or liquid form.
"It depends on how the tanks are built … how much volume the tanks have. This is very hard to say," Krag noted. The expectation is that the onboard propellant will be released and burn up at high altitude as the craft’s fuel tanks break apart during re-entry, he said.