A failed Russian probe designed to travel to a moon of Mars but stuck in Earth's orbit will come crashing down within hours, the Russian space agency said today. Roscosmos said the unmanned Phobos-Grunt will crash between 11:41am and 4:05pm EST. It could crash anywhere along the route of its next few orbits, which would include Europe, southeast Asia, Australia, and South America. The United States, Canada, and much of Russia are outside the risk zone.
A large part of each orbit is over water, and scientists have estimated that the risks of the probe crashing into any populated areas are minimal. At 14.9 tons, the Phobos-Grunt is one of the heaviest pieces of space junk ever to fall on Earth, and one of the most toxic. The bulk of its weight is 12 tons of highly toxic rocket fuel intended for the long journey to the Martian moon of Phobos. Roscosmos predicts that only between 20 and 30 fragments of the Phobos probe with a total weight of up to 440 pounds will survive the re-entry. It said all of the fuel will burn up entirely in the atmosphere. (Read more phobos-grunt stories.)