Article Posted on : - Nov 10, 2011

A full-scale mockup of Russia's Phobos-Grunt sample return spacecraft to Mars' moon Phobos. Photo: CNES.

MOSCOW (AP): A Russian space probe became stuck in orbit on Thursday after an equipment failure, raising fears it could come crashing down and spill tons of highly toxic fuel on Earth unless engineers can steer it back to its flight path.

One US expert said the spacecraft could become the most dangerous man-made object ever to hit the planet.

The mishap was the latest in a series of recent Russian failures that have raised concerns about the condition of the country's space industries.

The unmanned USD 170 million Phobos-Grunt craft was successfully launched by a Zenit-2 booster rocket just after midnight Moscow time (2016 GMT Tuesday) from the Baikonur cosmodrome in Kazakhstan.

It separated from the booster about 11 minutes later and was supposed to fire its engines twice to set out on its path towards Mars, but never did. The craft was aiming to get ground samples from Phobos, one of Mars' two moons.

Federal Space Agency chief Vladimir Popovkin said neither of the two engine burns worked, probably because the craft's orientation system failed.

He said engineers have three days to reset and fix the spacecraft's computer program before its batteries die, but the space agency later said the probe's orbit and its power sources could allow it to circle the Earth for about two weeks.

Russia news agencies cited space experts who offered widely varying estimates of how long the craft could stay in orbit before crashing down, from five days to one month.

James Oberg, a NASA veteran who now works as a space consultant, said it's still possible to regain control over the probe.

"This is not an impossible challenge," Oberg said in an email to The Associated Press. "Nothing irreversibly bad has happened, the full propellant load is still available, and short-term 'stay healthy' manoeuvres can be performed" like deploying the craft's solar panels to boost its power.

He warned, however, that if controllers failed to bring the Phobos-Grunt back to life, the tons of highly toxic fuel it carries would turn it into the most dangerous spacecraft ever to fall from orbit.