Why Not? Nasa Messenger Mission Image: Release Date 2 Nov 2011

Date acquired: October 20, 2011 Image Mission Elapsed Time (MET): 227593205 Image ID: 908832 Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS) Center Latitude: -54.77� Center Longitude: 211.1� E Resolution: 245 meters/pixel Scale: The large crater being crossed by Pourquoi Pas Rupes is 75 kilometers (47 miles) in diameter Incidence Angle: 76.0� Emission Angle: 28.7� Phase Angle: 82.5� Of Interest: Pourquoi Pas Rupes cuts dramatically through a crater in the upper left portion of this image. This rupes was named for the French ship Pourquoi Pas (which translates to "why not" in English), captained by Jean-Baptiste Charcot to explore the Antarctic region from 1908-1910. Check out MDIS images of other rupes, such as Beagle and Endeavour. This image was acquired as part of MDIS's high-resolution stereo base map. The stereo base map is used in combination with the surface morphology base map to create high-resolution stereo views of Mercury's surface, with an average resolution of 250 meters/pixel (0.16 miles/pixel or 820 feet/pixel) or better. During MESSENGER's one-year mission, the surface morphology base map is acquired during the first 176 days, and the second 176 days are used to acquire the complementary stereo base map, which includes the image here.

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington