An artist's rendering shows Opportunity exploring the surface of Mars. The rover parachuted to the planet's southern hemisphere Jan. 24, 2004, and is still producing well past its expected life span. The snazzier Curiousity landed elsewhere on the planet five months ago. (NASA via Associated Press)

An artist's rendering shows Opportunity exploring the surface of Mars. The rover parachuted to the planet's southern hemisphere Jan. 24, 2004, and is still producing well past its expected life span. The snazzier Curiousity landed elsewhere on the planet five months ago. (NASA via Associated Press)