The US space agency (Nasa) says the veteran Mars Global Surveyor spacecraft is probably lost and unrecoverable.
The orbiter entered a "safe mode" as it struggled to control a solar panel, and engineers have not been able to contact the probe since 2 November.
Nasa will use the Rover Opportunity on the surface of the Red Planet to try to speak to the 10-year-old spacecraft in the next couple of days.
However, mission offcials concede they are not expecting success.
"Realistically, we have run through the most likely possibilities for re-establishing communication, and we are facing the likelihood that the amazing flow of scientific observations from Mars Global Surveyor is over," said Fuk Li, Mars exploration programme manager at Nasa's Jet Propulsion Laboratory in Pasadena, California.
"We are not giving up hope, though."
Mars Global Surveyor (MGS) was launched in November 1996, operating longer than any other Martian craft.
Continued - http://news.bbc.co.uk/1/hi/sci/tech/6170778.stm
Ah, well... At least there are others there to carry on the good work. :/