Messenger Goes to Mercury

This enhanced-color view was created with a statistical technique that highlights subtle color variations seen in the 11 filters of MESSENGER’s wide-angle camera that are often related to composition. This region, viewed in detail for the first time during the third flyby, appears to have experienced a high level of volcanic activity. Source: NASA

This region of high reflectance was just barely seen on the limb during MESSENGER’s second flyby, but without enough detail to characterize it as anything other than a bright spot. Source: NASA

Detailed view of the interior of the double-ring basin in Image 4.3. This spectacular 290-km-diameter double-ring basin seen in detail for the first time during MESSENGER’s third flyby of Mercury bears a striking resemblance to the Raditladi basin, observed during the first flyby. Source: NASA

NASA's Mercury Surface, Space Environment, Geochemistry, and Ranging spacecraft—known as MESSENGER—will fly by Mercury for the third and final time on Sept. 29. The spacecraft will pass less than 142 miles above the planet's rocky surface for a final gravity assist that will enable it to enter Mercury's orbit in 2011.

Messenger will make its closest approach to Mercury Tuesday at about 6 PM, when it speeds by at about 12,000 mph. The planet's gravity is expected to slow Messenger by about 6,000 mph during the flyby and place it on track to enter orbit in March 2011.

The first image transmitted back to Earth following Messenger's first flyby of Mercury, a historic first look at the previously unseen side. This image, taken by the Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS), shows a closer view of much of that territory.

The craft's Wide Angle Camera (WAC), part of the Mercury Dual Imaging System (MDIS), is equipped with 11 narrow-band color filters. By combining images taken through different filters in the visible and infrared, the ship's data reveal Mercury in a variety of high-resolution color views not previously possible.

A close-up of Mercury's surface from <a href="http://www.foxnews.com/story/0,2933,434085,00.html">the last flyby in October 2008</a> shows volcanoes spewing "mysterious dark blue material."

By counting craters on different areas of Mercury's surface, a relative geologic history of the planet can be constructed, indicating which surfaces formed first and which formed later. This image shows a 172-mile wide portion of one frame taken with the Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS). In this image alone, 763 craters have been identified and measured (shown in green) along with 189 hills (shown in yellow).

During its closest approach to Mercury in 2008, Messenger's Narrow Angle Camera captured this close-up image of Mercury’s surface. The features in the foreground, near the right side of the image, are close to the terminator, the line between the sunlit dayside and dark night side of the planet, so shadows are long and prominent

Shadows reveal numerous small craters and intricate features in Mercury's Machaut crater. The largest crater within Machaut appears to have been inundated by lava flows similar to those that have filled most of the floor of the larger feature.