Overview of the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) missions

The Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR), the most advanced imaging radar system to have flown in Earth orbit, was carried in the cargo bay of the Space Shuttle Endeavour in April and October 1994. SIR-C/X-SAR simultaneously recorded data at three wavelengths (L-, C-, and X-bands; 23.5 cm, 5.8 cm, and 3.1 cm, respectively). In addition, the full polarimetric scattering matrix was obtained at L- and C-band over a variety of terrain and vegetation types. Scientists are using multifrequency, polarimetric SIR-C/X-SAR data in studies of geology, hydrology, ecology, oceanography, and radar remote sensing techniques. The October SIR-C/X-SAR flight also included acquisition of experimental repeat-pass interferometry data which have been used to generate digital elevation models and to detect surface motions in volcanic, tectonic, and glacial terrains. Results from SIR-C/X-SAR clearly show the increased value of using multiparameter and interferometric capabilities to characterize Earthʹs surface and vegetation cover and to generate geophysical products compared with optical sensors or single-channel radars alone.