Located 600 km south of Algiers, Algeria in the heart of the Sahara Desert, the five ksour (fortified villages) of the M'Zab Valley form an extraordinarily homogenous ensemble. Founded between 1012 and 1350, the M'Zab Valley has conserved practically the same way of life and the same building techniques since the 11th century. Each of these miniature citadels, surrounded by walls, is dominated by a mosque, the minaret of which functions as a watchtower. The mosque is conceived as a fortress; around this building, which is essential for communal life, are houses built in concentric circles up to the ramparts. The perspective view image was acquired October 8, 2003, and is located at 32.5 degrees north latitude, 3.6 degrees east 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/.