A NASA planetary exploration mission came to a planned, but nonetheless dramatic, end Thursday when it slammed into Mercury's surface at about 8,750 miles per hour and created a new crater on the planet's surface," NASA said in a statement.During its mission the spacecraft completed 4,104 orbits of Mercury and collected more than 277,000 images.NASA's Messenger spacecraft has slammed into the surface of the planet Mercury, ending a successful 11-year-mission.The MESSENGER mission will continue to provide scientists with a bonanza of new results as we begin the next phase of this mission - analysing the exciting data already in the archives, and unravelling the mysteries of Mercury.