Nearly two years after landing on the Red Planet, NASA exploration rovers Spirit and Opportunity continue to send back amazing images and information about Mars in a mission long outpacing expectations. Since landing on opposite sides of Mars in January 2004, the US space agency’s two robotic explorers have plowed over five kilometers of the planet’s surface and sent back more than 130,000 pictures, many of them stunning depictions of a desolate, arid but highly varied landscape. But what has equally pleased the National Aeronautics and Space Administration is that the two rovers have far exceeded their 90-day missions, lasting through one full Mars year–669 Mars days, the equivalent of 687 Earth days.