Mars Global Surveyor goes AWOL

NASA engineers have not been able to contact the agency's Mars Global Surveyor space craft for more than a week. Speculation is mounting that the craft, which has been in orbit around the red planet for the better part of a decade, might be entering a terminal decline.

The craft's communications with Earth petered out over several days. The last contact was on 5 November, two days after NASA instructed the craft to reposition its solar arrays to make the most of the sunlight.

After that instruction, the craft returned data that suggested it had a problem with a motor. NASA engineers sent a command that should have switched on a backup control circuits and motor, but apart from a weak signal on the 5th, they heard nothing in reply.

Engineers have asked for the Mars Reconnaissance Orbiter to take a picture of the Surveyor to see if there are any visual clues to what has gone wrong.

The working theory is that the orbiter has switched itself into safe mode and turned towards the sun to conserve power. It is possible that in doing so it has moved its communications gear out of alignment with the Earth. A picture of the craft may be able to confirm this.

It is also possible, NASA says, that it was hit by a micrometeorite, which could have knocked its antennae out of alignment.

The craft is programmed to turn its low gain antenna towards Earth if it has not received a signal for a while. This could mean it only has one solar panel in the Sun though, which would dramatically shorten its life expectancy. ®