NASA?s decision this week to give up trying to move stuckMars rover Spirit marks a major turning point in the plucky robot?s storiedsix-year history on the red planet, scientists say.
On Tuesday, NASA said that Spirit will staypermanently trapped in the deep Martian sand that snared it in the red planet'ssouthern hemisphere in May 2009.
?It?s kind of a poignant moment for us, you know,? saidSteve Squyres of Cornell University in Ithaca, N.Y., principal investigator of Spiritand its twin roverOpportunity, during the announcement. ?We built these vehicles with theintention of driving around the surface and Spirit has done that magnificentlyfor the better part of six years.?
Though it's sad to see the rover stop roving, scientistssay, Spirit can still do important work while standing still.
"There's months, if not years, of good-qualityleading-edge landed science we can do," said John Callas of NASA's JetPropulsion Laboratory in Pasadena, Calif., who is project manager of therovers.
Engineers are now trying to work the Spirit rover into apristine, permanent parking spot on Mars ? one that will position the vehiclein the best possible angle toward the sun to feed its top-mounted solar arraysto generate power. Meanwhile Opportunity is still mobile, and is currentlymaking its way to a large crater named Endeavour.
Spirit's transition from rover to stationary outpost on Marsis emotional for the scientists who have worked with the vehicle since itlanded on Mars in January 2004.
"We're scientists and engineers, but we're humantoo," Squyres told SPACE.com. "Over the course of a mission like thisyou get very attached to these things. You attach so much hopes, dreams,frustration, pride. When they're doing well, you're proud of them and when theydo badly you get angry and if they're about to stop doing what they do best, that'ssad."
But despite that sadness, mission managers are still thrilledthat Spirit kept moving this long.
"Every morning I come into work thinking, 'Boy, arethey still alive?'" Squyres said. "These things were designed to lastthree months and it's been six years."
Indeed, Spirit andOpportunity were both originally commissioned for 90-day missions, and weredesigned to travel about 0.6 miles (1 km). Spirit has trekked across 4.7miles (7.5 km), and Opportunity has traveled more than twice that far.
"We voided the warranty so long ago," Squyressaid. "Anybody who tells you that they expected Spirit to last this long,I think, is lying."
Given that the rovers are now in uncharted, unexpectedterritory, it's tough to predict how much longer they'll last. Spiritespecially will be vulnerable when Martian winter sets in a few months fromnow, because the sun will dip so low in the sky that the rover may have troublegathering enough solar energy to run itself and insulate its hardware.Opportunity at least can adjust its position to maximize its sun exposure.
Even if the end is nigh, the scientists said the rovermissions have been a resounding success.
"We're so far beyond predictions," Callas said."We're amazed that we got this much."
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