from Cape Canaveral Air Force Station, Fla., on August 3, 2004. It
returned to Earth for a gravity boost on August 2, 2005, then it will
fly past Venus twice, in October 2006 and June 2007. The spacecraft
uses the tug of Venus’ gravity to resize and rotate its trajectory
closer to Mercury’s orbit.
Three Mercury flybys, each followed about two months later by a course
correction maneuver, put MESSENGER in position to enter Mercury orbit
in March 2011. During the flybys – set for January 2008, October
2008 and September 2009 – MESSENGER will map nearly the entire
planet in color, image most of the areas unseen by Mariner 10, and
measure the composition of the surface, atmosphere and magnetosphere.
It will be the first new data from Mercury in more than 30 years –
and invaluable for planning MESSENGER’s yearlong orbital mission.