Earth Observation Mission News
Celebrating a Mission that changed how we use Radar
11 October 2019
11 October, 2019, marks the 25th anniversary of the end of a space mission that transformed the way we use radar to observe large-scale environmental processes on our home planet. The Spaceborne Imaging Radar-C and X-Band Synthetic Aperture Radar (SIR-C/X-SAR) mission made available to people worldwide the scientific data used to this day to inform decisions to slow and mitigate climate change.
The SIR-C instrument, built by NASA'S Jet Propulsion Laborator in Pasadena, California, and the X-SAR instrument, built by the German Aerospace Center (DLR), constituted the most advanced imaging radar system ever used in air or space. During hundreds of orbits on two flights aboard the Space Shuttle Endeavour, in April and October 1994, the radar system made multiple passes over 19 "supersites" — areas of scientific interest in such locations as the Sahara, Brazil, the Alps and the Gulf Stream. It also imaged events occurring during the flights, such as as a volcano erupting in Russia.
Image credit: NASA/JPL-Caltech - With SIR-C/X-SAR instruments mounted in the cargo bay atop the shuttle, the Endeavour crew flew upside down, using precise navigation, the hinge on the X-band antenna and "electronic steering" in the C- and L-band antennas to point the radars at "supersites" of scientific interest on Earth.