With all this attention on Spirit and Opportunity, it's easy to forget that robotic exploration of Mars is just getting started. NASA has plans for several more missions in the works, taking advantage of the launch windows that happen every two years. Next up: Mars Reconnaissance Orbiter, which is due to launch in 2005. It will take images of the Martian surface at a resolution small enough to see a beach ball. 2007 will see the launch of Phoenix, which will put a lander on the surface to search for organic molecules and water in the Martian soil. And then the Mars Science Laboratory is due to launch in 2009, which will be a rover the size of a minivan, designed to crawl the surface for up to two years.