NASA fears that unusually heavy dust storms taking place on Mars could permanently damage or disable the rovers exploring the Red Planet.
A series of severe Martian summer dust storms has blocked 99% of direct sunlight to the rover Opportunity. Its companion, Spirit, has been affected to a lesser extent. Both rely on solar panels to charge their batteries.
Scientists believe the st
orms could continue for several days, or even weeks.
"We're rooting for our rovers to survive these storms, but they were never designed for conditions this intense," said Alan Stern, associate administrator of Nasa's Science Mission Directorate in Washington.
The rovers will not be able to generate enough power to keep themselves warm and operating under reduced sunlight for much longer, Nasa said.
Before the storms, Opportunity's solar panels had been producing about 700 watt hours of electricity per day. The dust reduced the daily output to less than 400 watt hours, prompting the rover team to suspend driving and most observations.
Last Wednesday, Opportunity's solar-panel output dropped even further, to 128 watt hours. The rovers have been working on overtime since completing their primary three-month mission in 2004.
