October 17, 2011
Image Mission Elapsed Time (MET):
Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
The scene is about 230 km (143 mi.) across
North is up in this image.
Two large, highly degraded impact craters dominate this view. The top one is Delacroix. The southern rim of Delacroix cuts the northern rim of Shelley, indicating that Shelley is older. Both craters are ancient, with battered rims and interiors that have suffered countless impacts and infilling with volcanic and/or ejecta material.
Shelley is named for Percy Bysshe Shelley (1792–1822), an important English Romantic poet. His poem "Ozymandias" speaks of a ruined monument in the desert: "Round the decay/Of that colossal wreck, boundless and bare/The lone and level sands stretch far away." Such a description fits Shelley crater.
This image was acquired as part of MDIS's high-resolution stereo imaging campaign. Images from the stereo imaging campaign are used in combination with the surface morphology base map or the albedo base map to create high-resolution stereo views of Mercury's surface, with an average resolution of 200 meters/pixel. Viewing the surface under the same Sun illumination conditions but from two or more viewing angles enables information about the small-scale topography of Mercury's surface to be obtained.
The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation
are unraveling the history and evolution of the Solar System's innermost planet. Visit the Why Mercury?
section of this website to learn more about the key science questions that the MESSENGER mission is addressing. During the one-year primary mission, MESSENGER acquired 88,746 images and extensive other data sets. MESSENGER is now in a yearlong extended mission, during which plans call for the acquisition of more than 80,000 additional images to support MESSENGER's science goals.
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
For information regarding the use of MESSENGER images, see the image use policy.