Revered Spirit rover landed on Mars a decade ago
BY STEPHEN CLARK
Posted: January 3, 2014
Ten years ago Friday, the Spirit rover made an airbag-cushioned landing on Mars to begin a six-year exploration of Gusev Crater, outlasting even the most enthusiastic of prognostications from the mission's engineering and science teams.
Spirit's landing on Jan. 4, 2004, began a decade of unparalleled exploration on Mars, in which scientists learned the dusty world was once warmer and wetter.
Three weeks later, Spirit's twin rover Opportunity landed on the opposite side of Mars to survey a vastly different landscape.
Scientists selected Spirit's landing site in Gusev Crater based on imagery obtained from orbiters indicating the Connecticut-sized basin may have once held a lake. Spirit launched from Cape Canaveral, Fla., on June 10, 2003, on a Delta 2 rocket.
Opportunity ended up in a much richer environment of scientific targets than Spirit, finding multiple strands of evidence supporting the hypothesis that Mars was once wet and habitable. Steve Squyres, the chief scientist for the rovers at Cornell University, made the announcement less than six weeks after Opportunity landed.
It took longer for Spirit to reach scientific pay dirt. Controllers at NASA's Jet Propulsion Laboratory commanded the six-wheeled rover to drive toward a range of peaks named the Columbia Hills in remembrance of the astronauts who perished on space shuttle Columbia in 2003.
"In the Columbia Hills, we discovered compelling evidence of an ancient Mars that was a hot, wet, violent place, with volcanic explosions, hydrothermal activity, steam vents -- nothing like Mars today," Squyres said in a NASA press release.
NASA last heard from Spirit on March 22, 2010, before it succumbed to a Martian winter.
Spirit radioed data back to Earth for more than six years, vastly eclipsing the 90-day duration of its baseline mission. The probe carried a suite of cameras, a robot arm with a tool to grind into rocks, a microscopic imager and several spectrometers to measure mineral composition.
The failure of two of Spirit's wheels left the rover in an unfavorable position for winter. Engineers previously parked the rover on a slope facing the sun to keep the robot powered as sunlight diminished during the cold season, but Spirit was trapped in a sand pit and unable to move.
NASA officials said Spirit's critical components and connections may have been damaged by the cold temperatures, rendering the rover lifeless.
Opportunity is still going strong, having lasted nearly 10 years and traveled 24 miles across the red planet's treacherous surface in a region named Meridiani Planum.
"At Opportunity's landing site, we found evidence of an early Mars that had acidic groundwater that sometimes reached the surface and evaporated away, leaving salts behind. It was an environment with liquid water, but very different from the environment that Spirit told us about," Squyres said.
Opportunity is now on the trail of clay minerals on the rim of Endeavour Crater, a 14-mile-wide bowl carved by an ancient asteroid or comet impact.
"When Opportunity got to the rim of Endeavour Crater, we began a whole new mission," Squyres said. "We found gypsum veins and a rich concentration of clay minerals. The clay minerals tell us about water chemistry that was neutral, instead of acidic -- more favorable for microbial life, if any ever began on Mars."
Officials credit occasional Martian dust devils for the long lives of the rovers, especially Spirit, which had its power-generating solar panels cleaned of dust several times by gusts of wind blowing overhead.
Spirit drove 4.8 miles and snapped 128,000 images with its suite of cameras.
"Because of the rovers' longevity, we essentially got four different landing sites for the price of two," Squyres said.
We present some of our favorite images from Spirit's six-year mission.
This bird's-eye mosaic of the Spirit rover combines images of the spacecraft's instrument deck and a panorama of the surrounding Martian terrain. Spirit's panoramic camera captured images for this mosaic in August 2005 while the rover was on the summit of Husband Hill. See a larger version. Credit: NASA/JPL-Caltech/Cornell
This was the first color image of Mars taken by the panoramic camera on the Mars Exploration Rover Spirit. At the time, it was the highest resolution image ever taken on the surface of another planet. Credit: NASA/JPL-Caltech/Cornell
This panorama of Spirit's landing site in Gusev Crater was assembled from 225 frames shot by the rover in the first week after touching down on Mars on Jan. 4, 2004. See a larger version.
This image mosaic taken by the panoramic camera onboard the Spirit rover shows the rover's landing site, the Columbia Memorial Station, at Gusev Crater, Mars. The rover took this picture on Jan. 18 and 19, 2004, after driving off the stationary landing platform. See a larger version.
On May 19, 2005, NASA's Mars Exploration Rover Spirit captured this stunning view as the Sun sank below the rim of Gusev Crater on Mars. This Panoramic Camera mosaic was taken around 6:07 in the evening of the rover's 489th Martian day, or sol. See a larger version.
Credit: NASA/JPL-Caltech/Texas A&M/Cornell
Spirit and Opportunity each carried tributes to victims of the terrorist attacks of Sept. 11, 2001. This image from Spirit shows a piece of metal emblazoned with the American flag made of aluminum recovered from the World Trade Center site in New York after the towers fell.
Spirit's panoramic camera took this image Nov. 24, 2004, as the rover drove near Husband Hill in Gusev Crater. See a larger version. Credit: NASA/JPL-Caltech/Cornell
This frame from Spirit's navigation camera captured dust devils crossing the plains
of Gusev Crater on July 13, 2005. Credit: NASA/JPL-Caltech/Texas A&M
Spirit encountered a field of basaltic rocks formed when ancient lava solidified, as seen here in this image from Jan. 23, 2006, near Husband Hill at a feature named Lorre Ridge.
This close-up image taken by the Mars Exploration Rover Spirit's microscopic imager on June 18, 2004, highlights the nodular nuggets that cover the rock dubbed "Pot of Gold." These nuggets appear to stand on the end of stalk-like features. The surface of the rock is dotted with fine-scale pits. Data from the rover's scientific instruments have shown that Pot of Gold contains the mineral hematite, which can be formed with or without water. See a larger version.
A trench dug by Spirit's stuck right front wheel exposed a patch of nearly pure silica with the composition of opal. Scientists say the material could have formed in an ancient hot spring environment or an environment called a fumarole, in which acidic, volcanic steam rises through cracks. On Earth, such moist environments harbor microbial life. This is a false color image captured May 21, 2007, near a location dubbed "Home Plate" in the Columbia Hills. See a larger version.
While parked to conserve power during a Martian winter, Spirit acquired images for this panorama and self-portrait from April to October 2006. With dust accumulated on its solar panels, Spirit appears camouflaged on the rust-colored surface of Mars. See a larger version.
Credit: NASA/JPL-Caltech/Cornell/Arizona State University