January 3, 2011

Mars Rover Spirit Still Quiet

NASA's Mars rover Spirit has had its odometer stuck on 4.8 miles for more than 18 months and has not transmitted any data or signals since March 2010.

The Associated Press (AP) reports that Monday marks the rover's seventh year on the red planet and NASA doesn't know if Spirit is dead or alive, but is continuing to listen for any peep as the rover remains trapped in a sand trap.

"There's a realistic possibility that Spirit may never wake up again," Dave Lavery, Mars rover program executive at NASA headquarters, told AP's Alicia Chang.

Two Mars orbiters have been making daily overhead passes listening for any signals from Spirit, which became stuck in April 2009 while driving backward. After several unsuccessful attempts were made to free it, Spirit got new instructions to conduct science observations while immobile.

Nearly a year later, in March 2010, Spirit suddenly stopped talking with Earth and is believed by NASA to be in hibernation to conserve power. During this phase, communications and other activities are suspended so that energy can go to heating and battery recharging.

Spirit is designed to try to wake itself up when the battery has enough power. Scientists are disappointed with its silence, but are keeping hope alive that it will come back to life soon.

"I'm not ready to say goodbye yet," mission chief scientist Steve Squyres of Cornell University told Chang. "That moment will come someday, but now is not the time."

Spirit's solar panels rely on light from the Sun to charge. The Sun will continue to provide increased daily sunlight until it reaches its highest-point in the sky in mid-March. After that, the odds of the rover coming back online dwindle.

If Spirit doesn't transmit a signal by March, it's "probably not going to," Lavery said. But, he said, the mission will continue to listen after March, but will scale back the daily passes of the orbiters.

Spirit was designed to roam the Martian landscape for three months. But it, and its twin rover, Opportunity, have lived long past their lifespan. Spirit landed on Mars in January 2004, followed by Opportunity three weeks later. Both have discovered geologic evidence of ancient water on the planet.

Opportunity has so far logged 16.4 miles and shows no signs of stopping. It recently drove to a large crater where it will spend several months exploring. It will then move on to its next destination, the Endeavor crater.

Scientists can only reminisce about Spirit's past travels. "If that adventure is truly over, it will be a shame, but it will also have been a rover's life well-lived," astronomer Jim Bell, of Arizona State University, told the AP.


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