A Russian space probe that was intended to travel to a moon of Mars is instead coming crashing to Earth.

The unmanned Phobos-Grunt voyager is predicted to make re-entry on Sunday between 1641 and 2105 UTC, but exactly when and where is unknown.

The satellite was launched November 9, but it got stuck in Earth orbit and has been losing altitude since then.

The Russia's space agency, Roscosmos, says only small fragments of the 14-ton spacecraft weighing about 200 kilograms are expected to survive the atmosphere and will pose no danger. Some 11 tons of the spacecraft's weight is made up of unused toxic rocket fuel that Roscosmos says will burn up during re-entry.

The failure of the $165 million mission, which was designed to collect soil samples from the Martian moon Phobos, is among a series of recent setbacks for Russia's space program five decades after cosmonaut Yuri Gagarin's pioneering space flight.

Last August, an unmanned supply ship bound for the International Space Station crashed in Siberia.