A Russian spacecraft stranded in Earth orbit after a botched launch in November will plunge back into the atmosphere between Jan. 6 and Jan. 19, 2012, the Russian space agency Roscosmos said.

The Phobos-Grunt spacecraft was launched Nov. 8 on an ambitious mission to retrieve a soil sample from the Martian moon Phobos. (“Grunt” is Russian for “soil.”) But the probe never got farther than a couple of hundred miles from Earth after the spacecraft’s engines failed to ignite to put the probe on an interplanetary path to Mars.

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The exact time and place of re-entry won’t be known until shortly before the event, but Russia says the spacecraft’s toxic fuels will burn up during the plunge through the atmosphere and won’t pose an environmental or health risk.

Phobos-Grunt also contains 10 micrograms of radioactive Cobalt-57, which was to have been used to power one of the science instruments.

“It will not cause dangerous contamination,” a Google language translation of the Roscosmos statement said.

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Between 20 and 30 pieces of the spacecraft, with a total mass of about 200 kilograms (441 pounds) are expected to survive re-entry and land or splash down somewhere on Earth, the statement said.

Eleven tons of the spacecraft’s 13-ton weight is highly toxic rocket fuel.

Experts said that if the fuel has frozen, some could survive re-entry, posing a serious threat if it falls on a populated area.

Roscosmos however said the fuel will burn up about 100 kilometers (62 miles) above the ground.

The European Space Agency said it has been asked by Russia to try again on Tuesday to contact the troubled spacecraft.

Image: Artist’s illustration of Phobos-Grunt approaching Mars. Instead, it’s headed back to Earth. Credit: Roscosmos