FOREWORD

The Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) is the most advanced imaging radar system to have flown in Earth orbit. Carried in the cargo bay of the Space Shuttle Endeavour in April and October, 1994, SIR-C/X-SAR simultaneously recorded SAR data at three wavelengths (L-, C-, and X-bands; 23.5, 5.8 and 3.1 cm, respectively). In addition, the full polarimetric scattering matrix was obtained by the SIR-C instrument at L- and C-band over a variety of terrain and vegetation types. The integrated system is steerable in look angle (electronically in the case of SIR-C, mechanically in the case of X-SAR) to obtain data in the angular range of 15 -60 . Imaging resolution varies from about 10 to 50 meters, depending on the geometry and data taking configuration. Over the two flights, a total of 143 hours (93 terabits) of SAR data were digitally recorded on tape for subsequent processing in the U.S., Germany, and Italy. During the October 1994 flight of SIR-C/X-SAR, over one million square kilometers of repeat-pass SAR interferometry data were also obtained.

SIR-C/X-SAR is a cooperative experiment between the National Aeronautics and Space Administration (NASA), the German space agency, Deutsche Agentur für Raumfahrtangelegenheiten (DARA), and the Italian Space Agency, Agenzia Spaziale Italiana (ASI). SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies, with the Deutsche Forschungsanstalt für Luft- und Raumfahrt (DLR), the major partner in science, operations, and data processing. The experiment provides an evolutionary step in NASA's Spaceborne Imaging Radar (SIR) program that began with the Seasat SAR in 1978, and continued with SIR-A in 1981 and SIR-B in 1984. It also represents a continuation of Germany's imaging radar program which started with the Microwave Remote Sensing Experiment (MRSE) flown aboard the Shuttle on the first SPACELAB mission in 1983.

The SIR-C/X-SAR Science Team consisting of 52 investigator teams from more than a dozen countries are using SIR-C/X-SAR data in studies of geology, hydrology, ecology, oceanography. Other investigations are focused on topics in SAR calibration and electromagnetic theory. In addition, interferometric data from SIR-C/X-SAR are being used for topographic mapping, and surface change monitoring connected with tectonism, volcanism and glacier ice motion.

SIR-C/X-SAR data provide unique information for studying the health of the planet and its biodiversity, as well as critical data for natural hazards and resource assessments. The following papers summarize science results from the two flights of SIR-C/X-SAR. This report contains 44 investigator team reports and several additional reports from co-investigators and other researchers. At the time of this writing, processing and analysis of SIR-C/X-SAR data are continuing. Since the SIR-C/X-SAR flights in 1994, hundreds of additional investigators have accessed SIR-C/X-SAR data for studies as diverse as archeology, land-use, and resource management indicating that new findings and discoveries can be expected from this rich and varied data set for many years to come.

This document can be found at the following World Wide Web site:

http://southport.jpl.nasa.gov/ProgressReports0496/

D. L. Evans
J. J. Plaut, editors

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