Russia raced on Thursday to salvage a spacecraft bound for a moon of Mars that is stranded in the Earth's orbit, with just days left before the window closes on its first interplanetary mission in 15 years.
So far Russian controllers have failed to establish contact with the $163-million, unmanned probe, leaving little hope of recovering the ambitious mission that was to reassert Russia's place at the front lines of space exploration.
Following the launch from Russia's Baikonur launch pad in Kazakhstan early on Wednesday, the Phobos-Grunt probe is stuck in a dangerously low orbit, creating a drag that could eventually send it crashing back to Earth.
Russia's space agency said it had at least three days to try to fix the problem and steer the craft on to its correct path, and will make another attempt when it passes over Baikonur later today, a spokesman said.
Failure so soon after lift off in the three-year mission to bring back soil -- "grunt" in Russian -- from the Martian moon Phobos would be a major blow to the pride of the Russian space industry, adding to a humiliating series of setbacks.
"So far all efforts to communicate with the craft have been unsuccessful," lead mission scientist Alexander Zakharov of Moscow's Space Research Institute told Reuters.
"They are trying everything including visual methods to try to assess what is wrong with it, but of course the situation doesn't inspire much hope."
Experts say the post-launch problems are linked to the craft's on board flight computer, which failed to fire two engine burns to send it on its trajectory toward Mars.
There is a small chance the software could be reprogrammed, if controllers can link with the craft. But if the troubles are hardware related, the mission is likely lost, Zakharov and other industry sources said.
Russia is relying on a single ground site to try to reach the craft once every few hours along its orbit.
"In my opinion Phobos-Grunt is lost," Vladimir Uvarov, a former chief Russian military expert on space, told the state-run Rossiiskaya Gazeta.
China also could be disappointed after entrusting its first interplanetary Mars satellite, Yinghuo-1, to piggyback on the mission.
Phobos-Grunt is also carrying bacteria, plant seeds and tiny animals known as water bears, part of a U.S. study to see if they could survive beyond the Earth's protective bubble.
The plan was for Phobos-Grunt to reach Mars' orbit next year, touch down on the larger of its two tiny moons in 2013, collect a sample from the surface and fly back to Earth in 2014.
Dust from Phobos, scientist say, would shed light on the genesis of the solar system and Mars' enduring mysteries.
If it is lost, it will join a long string of over a dozen Soviet and Russian missions to fail en route to Mars, while U.S. rovers have logged hundreds of hours on the Red Planet.
When the first post-Soviet Mars-96 probe broke up over the Pacific, it was seen as a proof of the industry's deterioration after a generation of brain drain and crimped budgets.
NASA will launch a $2.5 billion rover designed to assess the planet's suitability for life later this month, toward the end of a launch window for Mars flights that comes every 780 days.
If Phobos-Grunt cannot be bounced out of orbit, the massive craft will eventually crash back to Earth with a full payload of toxic hydrazine and nitrogen tetroxide fuel and small cargo of radioactive cobalt-57.
It is unclear how much of it will survive the fiery plunge through the atmosphere.
(Editing by Rosalind Russell)