A Russian mission to fly a probe to one of Mars' moons and bring back samples of its soil has failed.
The craft was successfully launched towards Phobos from the Baikonur cosmodrome in Kazakhstan on Tuesday night.
But after the Phobos-Grunt probe separated from a Zenit-2 booster rocket, its engines failed to fire up and the planned journey to the Red Planet ended.
Russia's Federal Space Agency chief Vladimir Popovkin said neither of the two iginitions worked, probably due to the failure of the craft's orientation system.
Russian news reports quoted Mr Popovkin as saying that space engineers have three days to reset the craft's computer programme to make it work before its batteries die.
The embarrassing failure is the latest in a series of problems that have raised concerns about the condition of the nation's space industries.
The \$170m (£105m) Phobos-Grunt would have been Russia's first interplanetary mission since Soviet times.
It was originally set to blast off in October 2009, but its launch was postponed because the craft was not ready.
The 13.2 metric ton (29,040lbs) craft is the heaviest interplanetary probe ever, with fuel accounting for most of its weight.
Its manufacturer, NPO Lavochkin, was also responsible for a failed robotic mission to Mars in 1996.
On that occasion the probe crashed into the Pacific Ocean following engine failure.
NPO Lavochkin's chief Viktor Khartov described the current mission as essential to maintain the nation's technological expertise in robotic missions to other planets.
"This is practically the last chance for the people who participated in the previous project to share their experience with the next generation, to preserve the continuity," Khartov said before the launch, according to the Interfax news agency.
Scientists hoped that studies of the Phobos soil could help solve the mystery of its origin and shed more light on the genesis of the solar system.
Some believe that the crater-dented moon is an asteroid captured by Mars' gravity, while others think it is a piece of debris resulting from Mars' collision with another celestial object.