Russia's space agency Roscosmos said the unmanned Phobos-Ground willl crash between 16:41 and 21:05 GMT (11:41am and 4:05pm EST) Sunday. It could crash anywhere along the route of its next few orbits, that would include Europe, southeast Asia, Australia and South America. The US, Canada and much of Russia are outside the risk zone.
Scientists have estimated that the risk of the probe crashing into any populated areas are minimal.
Roscosmos predicts that only between 20 and 30 fragments of the Phobos probe with a total weight of up to 200 kilograms (440 pounds) will survive the re-entry and plummet to Earth. It said its load of toxic rocket fuel will burn up entirely in the atmosphere.