In the fall of 1863, Confederate General Braxton Bragg's army occupied the mountains that ring the vital railroad center of Chattanooga, on the Tennessee River. Union General Ulysses Grant, brought in to save the situation, steadily built up offensive strength, and on November 23-25 burst the blockade in a series of brilliantly executed attacks. Union forces pushed Confederate troops away from Chattanooga. The victory set the stage for General Sherman's Atlanta Campaign. The image was acquired October 17, 2010, and is located at 35 degrees north latitude, 85.3 degrees west longitude.
With its 14 spectral bands from the visible to the thermal infrared wavelength region and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet. ASTER is one of five Earth-observing instruments launched Dec. 18, 1999, on Terra. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and data products.
The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.
The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate, Washington, D.C.
More information about ASTER is available at http://asterweb.jpl.nasa.gov/.