April 1, 2010

Spirit Misses Scheduled Communication

NASA's Jet Propulsion Laboratory said Wednesday that the sand-trapped Mars rover Spirit failed to make a scheduled communication this week and may have gone into a power-saving hibernation to survive the planet's winter.

Spirit was expected to communicate with the orbiting Mars Odyssey spacecraft on Tuesday.

"We are checking other less likely possibilities for the missed communication, but this probably means that Spirit tripped a low-power fault sometime between the last downlink on March 22 and yesterday," Mars rovers project manager John Callas said in a statement.

Spirit survived previous winters by positioning itself with its solar panels lifted towards the sun.  However, it has been stuck in the sand for about a full Earth year and with two of its six wheels not working NASA decided in January to leave it be and use it for stationary science. 

The amount of sunlight falling on its panels is declining.

Callas said that recent downlinks from Spirit had shown the battery's charge was getting lower.

Hibernation mode suspends communications and other activities so energy can go to heating and battery recharging.  The rover, which has been on the Red Plant since 2004, is designed to try to wake up when there is enough charge and to communicate on schedule.

"We may not hear from Spirit again for weeks or months, but we will be listening at every opportunity, and our expectation is that Spirit will resume communications when the batteries are sufficiently charged," Callas said.

However, NASA said that in coming weeks Spirit's core electronics will become colder than they ever have since it landed in January 2004.

NASA said that temperatures should not be lower than the electronics were designed to withstand "but with the age of the rover adds to the uncertainty of survival."

When Spirit and its twin Opportunity were launched from Earth in 2003, they were expected to last three-months.  Instead, they have lasted six years.  Opportunity still continues to roam around the planet.


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