

This view from the panoramic camera on NASA's Mars Exploration Rover Spirit shows the terrain surrounding the location called 'Troy,' where Spirit became embedded in soft soil during the spring of 2009. The track on the right is more evident because Spirit was driving backwards, dragging its right-front wheel, one of two wheels which no longer rotates. The bright soil in the center foreground is soft material in which Spirit became embedded after the wheels on that side cut through a darker top layer. NASA/JPL
An artist's impression of a NASA's Mars Exploration Rovers exploring the surface of the Red Planet is seen. The Spirit rover has worked on Mars for more than 69 months in what was originally planned as a three-month mission. NASA
The Spirit rover undergoes a final checkout on March 28, 2003, in the Payload Hazardous Servicing Facility at Kennedy Space Center. Attached to the unit's antenna is a plaque commemorating the STS-107 Space Shuttle Columbia crew. NASA
Spirit was instructed to closely inspect some interesting rocks near the summit of 'Husband Hill' in September 2005. Spirit's Panoramic Camera captured the rover's Instrument Deployment Device above as moved to get a closer look at an outcrop of rocks named Hillary. NASA/JPL
Amid billows of smoke and steam, the Delta II rocket carrying NASA's Spirit rover lifts off at Cape Canaveral Air Force Station on June 6, 2003. NASA
This bird's-eye view combines a self-portrait of the spacecraft deck and a panoramic mosaic of the Martian surface as viewed by NASA's Mars Exploration Rover Spirit. The rover's solar panels are still gleaming in the sunlight, having acquired only a thin veneer of dust two years after the rover landed and commenced exploring the red planet. Spirit captured this 360-degree panorama on the summit of 'Husband Hill' inside Mars' Gusev Crater. NASA/JPL-Caltech/Cornell
NASA's Mars rovers keep getting bigger. This photo provides a comparison of the wheel sizes for three generations of them. The first rover on Mars was Sojourner, on the Mars Pathfinder mission launched in 1996. It was small and didn't go far. The Mars Exploration Rovers Spirit and Opportunity, launched in 2003, are bigger and have driven many times farther than expected. The Mars Science Laboratory, in development for a 2011 launch, represents another leap in capability. NASA/JPL-Caltech
The Mars Exploration Rover Spirit is tested rolling off the northeastern side of the lander at JPL's In-Situ Instruments Laboratory prior to being launched. NASA/JPL
After leaving its nest, the Spirit rover turned to capture this spectacular view over the Columbia Memorial Station and the floor of Gusev crater. In the foreground lies the 2-meter wide lander platform surrounded by deflated airbags and the egress ramp used by the rover to complete its journey to the martian surface. NASA/JPL
This 360-degree view, called the 'McMurdo' panorama, comes from the panoramic camera (Pancam) on NASA's Mars Exploration Rover Spirit. From April through October 2006, Spirit had stayed on a small hill known as 'Low Ridge.' There, the rover's solar panels are tilted toward the sun to maintain enough solar power for Spirit to keep making scientific observations throughout the winter on southern Mars. NASA/JPL
The Spirit rover recorded this forward view of its arm and surroundings on Oct. 11, 2009. Bright soil in the left half of the image is loose, fluffy material churned by the rover's left-front wheel as Spirit, driving backwards, approached its current position in April 2009 and the wheel broke through a darker, crusty surface. The turret of tools at the end of the rover's robotic arm is positioned with the Moessbauer spectrometer up and the rock abrasion tool extending toward the right. Spirit's right-front wheel, visible in this image, has not worked since 2006. This may be the final resting place of the Spirit rover. NASA/JPL-Caltech