Return to Mercury: the MESSENGER spacecraft and mission

NASA's MESSENGER mission, part of its Discovery program, is the first mission to return to the planet Mercury since the Mariner 10 flybys in 1974 and 1975. The spacecraft incorporates many innovative features, including a sunshade made of ceramic cloth for protection from the Sun, a pair of electronically steerable phased-array antennas, and specially hardened solar panels. A suite of seven miniaturized science instruments, along with the antennas, will globally characterize the planet's composition, structure, atmosphere, and charged particle environment. MESSENGER was launched on August 3, 2004, and performed its single Earth flyby on August 2, 2005. The spacecraft will make two flybys of Venus and three of Mercury prior to orbiting the planet for one Earth-year beginning in March 2011. Highlights of a busy first year of flight operations include initial testing of all spacecraft systems and instruments, execution of six trajectory control maneuvers, and instrument observations of the Earth and Moon surrounding the August flyby.