The Spirit rover at Mars was designed to last through a three-month mission. But now, more than seven years later, NASA has finally decided to give up on the efforts to communicate with the long-lived electronic explorer that had become stranded in the sand. The extended mission is effectively over.

A transmission to Spirit on May 25 is set to be the last in a series of attempts to contact the rover, which last sent data to engineers on Earth on March 22, 2010. Since then, engineers had held out hope that Spirit and its solar-powered heaters would reawaken after a winter in weak sunlight that was the coldest it ever experienced.

Photographer Ken Kremer painstakingly compiled this mosaic of a sand-trap close-up taken on sol (Martian day) 2,174 from some of Spirit's final images of Mars. Spirit's last panorama was snapped on the following sol.

NASA is now turning its communications assets toward preparation for the agency's next mission to the Red Planet, set to launch in November—the Mars Science Laboratory rover, Curiosity.

Radio antennas with NASA's Deep Space Network will occasionally listen for signals from Spirit—just in case—says Dave Lavery, NASA's program executive for solar system exploration. Meanwhile, Spirit's twin, the Opportunity rover, continues its 19-kilometer journey to Endeavour Crater on the opposite side of planet.

—Robin Lloyd