Tomorrow afternoon, the MESSENGER spacecraft will pass a mere 228 kilometers (142 miles) above Mercury's surface. The NAC image shown here was taken 55 hours prior to tomorrow's closest approach, which will occur at 5:55 pm EDT. The mission's third Mercury flyby offers special opportunities for new science observations. Read about the unprecedented targeted observations planned for the encounter or learn about some of the MDIS imaging highlights that will occur tomorrow, including imaging of a portion of Mercury's surface previously unseen by spacecraft. This image shows much of that previously unseen terrain but at a much lower resolution than will be obtained when the spacecraft is closer to the planet during the flyby tomorrow.

Date Acquired: September 27, 2009
Image Mission Elapsed Time (MET): 162550738
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 17 kilometers/pixel (11 miles/pixel)
Scale: Mercury's diameter is 4880 kilometers (3030 miles)
Spacecraft Altitude: 672,000 kilometers (418,000 miles)

These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.