Unlike Juno, which will take the first steps into its life as a planet inspector in 2011, the Mercury orbiter Messenger
is reaching the climax of its career. Mercury
is small, dense, hot, and relatively unexplored--and on March 18 Messenger will drop into orbit around the planet for a year-long investigation. Messenger has already completed three fly-bys of our solar system's innermost planet, taking high resolution images of the planet and identifying areas of interest. Once in orbit, Messenger will map the planet's the magnetic field and topography, characterize its atmosphere, and search for ice at the permanently shaded polar regions.