closest planet to the sun hasn't received as much scientific attention as some of its more flashy solar system neighbors, such as Mars, but NASA's Messenger spacecraft is helping to close the gap. The probe has been in orbit around Mercury since March 2011, and its team announced Feb. 28 that the spacecraft had finished mapping the planet's surface. Scientists use images from NASA's Messenger spacecraft to create these global views of Mercury, the most complete maps ever. The images were released on Feb. 22, 2013. This photo made available by NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington on Tuesday, Nov. 27, 2012 shows a 68-mile-diameter crater, large indentation at center, in the north polar region of Mercury which has been shown to harbor water ice, thanks to measurements by the Messenger spacecraft. Scientists made the announcement Thursday, Nov. 29, 2012. (AP Photo/NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington) The radar image of Mercury’s north polar region from Image 2.1 is shown superposed on a mosaic of MESSENGER images of the same area. All of the larger polar deposits are located on the floors or walls of impact craters. Deposits farther from th Shown in red are areas of Mercury’s north polar region that are in shadow in all images acquired by MESSENGER to date. Image coverage, and mapping of shadows, is incomplete near the pole. The polar deposits imaged by Earth-based radar are in ye The central peaks of this complex crater on Mercury formed in such a way that it resembles a smiling face. This image was taken by NASA's Messenger spacecraft. These image of Mercury by NASA's Messenger probe show the distinctive color of the planet's northern plains and their surrounding terrain. The top image is as Messenger saw the scene, with the bottom image enhanced to bring out features. Image Craters photographed by MESSENGER spacecraft may appear to resemble a familiar television character, a favorite of children. Image acquired August 29, 2012.