This X-band image of the volcano Kilauea was taken on October 4, 1994, by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar. The area shown is about 9 kilometers by 13 kilometers (5.5 miles by 8 miles) and is centered at about 19.58 degrees north latitude and 155.55 degrees west longitude. This image and a similar image taken during the first flight of the radar instrument on April 13, 1994 were combined to produce the topographic information by means of an interferometric process. This is a process by which radar data acquired on different passes of the space shuttle is overlaid to obtain elevation information. Three additional images are provided showing an overlay of radar data with interferometric fringes; a three-dimensional image based on altitude lines; and, finally, a topographic view of the region.

Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity.

SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI), with the Deutsche Forschungsanstalt fuer Luft und Raumfahrt e.V.(DLR), the major partner in science, operations and data processing of X-SAR. The Instituto Ricerca Elettromagnetismo Componenti Elettronici (IRECE) at the University of Naples was a partner in interferometry analysis.