Maestro

NASA's twin robot geologists, the Mars Exploration Rovers, launched toward Mars on June 10 and July 7, 2003, in search of answers about the history of water on Mars.

They landed on Mars January 3 and January 24 PST, 2004 (January 4 and January 25 UTC, 2004). The Mars Exploration Rover mission is part of NASA's Mars Exploration Program