2001 Mars Odyssey (U.S.)
Destination: Mars. Launched: April 7, 2001. Arrival: Oct. 24, 2001. Mission: To conduct mineralogical mapping of the planet and study the radiation risk to humans over the course of three years. A goal of the program is to determine if Mars's atmosphere could support life.
Mars Odyssey's primary mission of mapping the amount and distribution of chemical elements and minerals that form the Martian surface and searching for evidence of hydrogen in the subsurface was completed in Aug. 2004. Mars Odyssey also provides support to the Mars Exploration Rovers program (MER), serving as the communications relay for MER's rovers. About 85% of MER's rovers' pictures have been relayed to Earth via Odyssey.