ITHACA, N.Y. -- One hundred fifty million miles away, a Mars rover is in a bit of trouble. A dust storm on Mars has reduced the amount of sunlight reaching the solar panels on NASA's Spirit Rover. It's at its lowest power level ever.

"Before this big dust storm, the lowest that we'd seen was about 200-250 watt hours. Now we're down below 100," said Jim Bell, a Cornell University professor of astronomy.

That's not even enough power to run a 100-watt light bulb for one hour.

Spirit had up to 1,000 watt hours when it first landed on Mars, searching for evidence that the planet was once inhabitable. If it's power level gets too low, Spirit will go into a preservation mode, making it difficult for scientists to communicate with it from Earth.

"It's a very serious situation, with the rover. We were very, very paranoid for the first few months that any moment could be our last," said Bell.

Even though this dust storm could have a serious impact on the rover, Bell says he doesn't think this will be the end for Spirit.

"I think we'll get out of it. To me, it seems a little early for a long, extended dust storm," said Bell.

Just like certain parts of the Earth have a snow storm seasons, Bell says there are similar seasons on Mars when dust storms are likely to occur. Cornell scientists are working with experts at the Jet Propulsion Lab in California to make sure that Spirit survives this storm.

"All kinds of noncritical systems are being shut down to conserve energy. We already had parked the rover at an orientation to maximize the tilt into the sun to increase energy potential there," said Bell.

A simple gust of wind could easily clear the dust from the rover. The next opportunity scientists have to communicate with Spirit will be Thursday.

Cornell also programs an identical rover called Opportunity. It's on the other side of Mars and has not been affected by this dust storm.