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Spirit Surprise: Long-Defunct Mars Rover Wheel Spins

Spirit Surprise: Long-Defunct Mars Rover Wheel Spins
This three-frame animation aids evaluation of performance of the right-front wheel on NASA's Mars Exploration Rover Spirit during a drive on the rover's 2,117th Martian day, or sol (Dec. 16, 2009). This wheel, on the right side of the images, had stopped operating in March 2006 and had not been used for driving since then. However, it revolved with apparently normal motion during the first three of four driving segments on Sol 2117. It completed about 10 rotations, then it stopped early in the fourth segment of the drive. Whether it will work again on future drives is uncertain.
(Image: © NASA/JPL-Caltech)

Thelong-crippled right-front wheel of NASA's beleaguered Mars rover Spiritsurprised mission managers by spinning for the first time in three years lastweek.

NASAengineers decided to try switching on the bum wheel to see if they could gainmore traction to try to extricatethe rover from the sand trap it has been stuck in since May 6.

Engineerswere "totally" surprised that the wheel actually showed signs ofactivity last week after being switched on for the first time since 2006, whenits failure due to an open circuit was thought to be permanent, said RayArvidson of Washington University in St. Louis. Arvidson is deputy principalinvestigator for the science payloads on Spirit and its twin rover, Opportunity. That wheel failure forced engineers to drive thespacecraft backwards with the crippled wheel in tow.

"We'vebeen dragging it around Mars for three years," Arvidson said.

The attemptto switch on and move the right-front wheel was expected to be a long-shot,"but at this point we need every bit of traction we can get,"Arvidson said.

Theright-front wheel isn't working perfectly – while it revolved with apparentlynormal movement during the first three of four driving segments on Dec. 16, itstopped early in the fourth segment. Whether or not it will work again isunclear, according to the latest NASA progress report on the rover.

Spirit'sright-rear wheel still isn't budging since it began experiencing a set ofstalls in November.

Mission managers are unsure about theprospects of freeing the rover.

"Idon't know if we're going to get it out frankly," Arvidson told SPACE.com.

But theteam plans to continue the slow process of attempting to drive out of the sandtrap into the new year – the seventh that Spiritand Opportunity have been on Mars, Arvidson said.

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