A €120m unmanned Russian spacecraft on a mission to a moon of Mars has failed to take its course to the red planet.
Russian space agency chief Vladimir Popovkin said an engine failed to fire on the Phobos-Grunt probe after it reached Earth's orbit.
Moscow space officials now have just three days to jolt it out of orbit before its batteries run out.
''The engine did not fire, neither the first nor the second burn occurred. This means that the craft was unable to find its bearings by the stars," state television quoted Mr Popovkin as saying.
The mission to bring back a sample of soil from the Martian moon Phobos was supposed to assert Russia's place at the front line of space exploration.
However, if Moscow cannot bounce it out of orbit, the Phobos probe could become several tonnes of expensive space junk circling the Earth.
"They say there is hope to reset it, apparently it's a problem with the programming but there is very little time," the lead mission scientist Alexander Zakharov of the Space Research Institute told Reuters.
The probe blasted off at 12.16am Moscow time (8.16pm last night) from the Baikonur launch pad on a Zenit-2SB rocket - starting what is meant to be a three-year trip to Phobos and back.
The plan is for Phobos-Grunt to reach Mars next year, touch down on the larger of Mars' two tiny moons in 2013, collect a sample from the surface and fly back to Earth in 2014.
Dust from Phobos, scientists say, could shed light on the genesis of the solar system, and data collected on the voyage might help solve enduring mysteries such as whether Earth's neighbour has ever supported life.
If successful, its long journey would be the first Soviet or Russian deep-space probe to Mars to fulfil its mission completely.
Russian scientists have dreamed of probing the Red Planet's potato-shaped satellite Phobos, a mere 22km across, since the 1960s heyday of pioneering Soviet forays into space.
But two Phobos missions sent up in 1988 failed, one going silent within metres of the surface.
In 1996, another unmanned Russian craft bound for Mars broke up in the atmosphere after a botched launch.
