NASA's twin robot geologists, the Mars Exploration Rovers, Opportunity and Opportunity, launched from Earth on June 10 and July 7, 2003. Their mission was to search of answers about the history of water on Mars. They landed on Mars January 3 and January 24 PST, 2004. As geologists, the rovers are have goals of searching for and characterizing a wide range of rocks and soils that marsopportunitypicturesrover with astronomybookmarks