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As reported by the U.S. National Aeronautics and Space Administration on March 29, 2011:
MESSENGER has delivered its first image since entering orbit about Mercury on March 17. It was taken today at 5:20 am EDT by the Mercury Dual Imaging System as the spacecraft sailed high above Mercury’s south pole, and provides a glimpse of portions of Mercury's surface not previously seen by spacecraft. The image was acquired as part of the orbital commissioning phase of the MESSENGER mission. Continuous global mapping of Mercury will begin on April 4.
"The entire MESSENGER team is thrilled that spacecraft and instrument checkout has been proceeding according to plan," says MESSENGER Principal Investigator Sean Solomon, of the Carnegie Institution of Washington. "The first images from orbit and the first measurements from MESSENGER’s other payload instruments are only the opening trickle of the flood of new information that we can expect over the coming year. The orbital exploration of the Solar System’s innermost planet has begun."
As reported by Space Daily on March 31, 2011:
The first image acquired by MESSENGER from orbit around Mercury was actually part of an eight-image sequence, for which images were acquired through eight of the WAC's eleven filters...
...One of MESSENGER's measurement objectives is to create an eight-color global base map at a resolution of 1 km/pixel (0.6 miles/pixel) to help understand the variations of composition across Mercury's surface.
On March 17, 2011 (March 18, 2011, UTC), MESSENGER became the first spacecraft ever to orbit the planet Mercury. The mission is currently in its commissioning phase, during which spacecraft and instrument performance are verified through a series of specially designed checkout activities.
In the course of the one-year primary mission, the spacecraft's seven scientific instruments and radio science investigation will unravel the history and evolution of the Solar System's innermost planet.
Go here to follow the progress of MESSENGER's mission.