With just two days until MESSENGER's closest pass by Mercury, the Mercury Dual Imaging System (MDIS) is acquiring sets of images twice a day. These images are used for optical navigation purposes, to verify that the spacecraft is on the desired course. The images also provide the first glimpse of Mercury by a spacecraft in over 30 years, since the Mariner 10 mission in 1974 and 1975, and hint at the exciting images to come in the next week. This image was snapped on January 11, 2008, when MESSENGER was at a distance of about 1.7 million kilometers (1.1 million miles) from Mercury. The diameter of Mercury is about 4880 kilometers (3030 miles), and this image has a resolution of about 44 kilometers/pixel (27 miles/pixel).

MESSENGER will pass 200 kilometers (124 miles) above Mercury's surface on Monday, January 14, 2008, at 19:04:39 UTC (2:04:39 pm EST). Extensive scientific observations are planned during this historic flyby, including imaging a large portion of Mercury's surface that has never before been seen by a spacecraft. These data will be used to address fundamental questions about Mercury's formation, evolution, and the history of our solar system.

Image acquired on January 11, 2008, 09:06 UTC.

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington