MESSENGER imaged Mercury's partially sunlit surface on its approach to the planet yesterday. This WAC image reveals approximately an additional 5% of the surface (outlined in red) that had been previously unseen by spacecraft. Among the many newly imaged surface features are impact craters, smooth plains, and an intriguing double-ring basin approximately 260 kilometers (125 miles) in diameter. Rembrandt basin straddles Mercury's terminator (along the right side of the image).

Date Acquired: September 29, 2009
Image Mission Elapsed Time (MET): 162741055
Instrument: Wide Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
WAC Filter: 7 (750 nanometers)
Resolution: 4.8 kilometers/pixel (3.0 miles/pixel)
Scale: Mercury's diameter is 4880 kilometers (3030 miles)
Spacecraft Altitude: 26,900 kilometers (16,700 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.