NASA's Messenger spacecraft passes over the horizon of Mercury (January 2008).
Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
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.