MESSENGER is the first mission sent to orbit the planet closest to the sun. On Oct. 6, 2008, at roughly 4:40 a.m. ET, MESSENGER flew by Mercury for the second time this year. During the encounter, the probe swung just 125 miles (200 kilometers) above the cratered surface of Mercury, snapping hundreds of pictures and collecting a variety of other data from the planet as it gains a critical gravity assist that keeps the probe on track to become the first spacecraft ever to orbit the innermost planet beginning in March 2011.

At roughly 1:50 a.m. ET on October 7, MESSENGER's most recent images began to be received back on Earth. The spectacular image shown here is one of the first to be returned. It shows Mercury about 90 minutes after the spacecraft’s closest approach. The bright crater just south of the center of the image is Kuiper, identified on images from the Mariner 10 mission in the 1970s.

For most of the terrain east of Kuiper, toward the limb (edge) of the planet, the departing images are the first spacecraft views of that portion of Mercury’s surface. A striking characteristic of this newly imaged area is the large pattern of rays that extend from the northern region of Mercury to regions south of Kuiper.