The window to contact the stranded Phobos-Grunt and send it on its mission to the Martian moon has now closed.
The craft could still fly by the Red Planet, but it will no longer be able to complete its exploration of the Martian moon Phobos and return to Earth, space industry sources told Russian state news agency RIA Novosti.
Over the last two weeks, there was no clear response from attempts to get in contact with the Mars probe, which got stuck in Earth's orbit when its engines failed to fire and send it on its way to the Red Planet.
If Russia wants to try again to get a spaceship to Mars, or indeed has the billion or so rubles it will need to try again, the next opportunity will be 2014.
Russian space boffins have been trying for weeks to rescue the Phobos-Grunt, which launched successfully but never set out from Earth's orbit on its mission.
The attempt was always something of a long shot, since establishing any contact was difficult given the small windows during which it was in range of an earth-to-space communication centre, and even if they got in touch, there was no guarantee they could get the engines going.
A Russian space expert said last week that if the probe failed to get to Mars, the space agency should still keep trying to get in touch because it could maybe make it to Earth's Moon instead.
Failing that, just getting the craft to land on Earth instead of crashing through the atmosphere could allow the agency to recover equipment from the ship and even readings from its instruments.
If all attempts to contact the Phobos-Grunt fail, it will eventually fall out of Earth's orbit and crash through the atmosphere.
Vladimir Popovkin, head of the Russian space agency, has dismissed fears that it could crash into civilian areas, saying that the 7.5 metric tonnes of fuel aboard the craft in aluminium tanks would ensure it exploded on re-entry.
However, earlier today a source told RIA Novosti that some heat-resistant parts of the probe could fall to earth.
Russian space sources have also variously given the Phobos-Grunt until December, January or even March to fall out of the sky. ®