NORTH DAKOTA STATE UNIVERSITY - FARGO, N D
NORTH DAKOTA, MINNESOTA,
SIR-C/X-SAR (Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar) is a joint project of the National Aeronautics and Space Administration (NASA), the German Space Agency, and the Italian Space Agency. An imaging radar works very like a flash camera in that it provides its own light to illuminate an area on the ground and take a snapshot picture, but at radio wavelengths. A flash camera sends out a pulse of light (the flash) and records on film the light that is reflected back at it through the camera lens. Instead of a camera lens and film, a radar uses an antenna and digital computer tapes to record its images. In a radar image, one can see only the light that was reflected back toward the radar antenna (NASA-JPL).
An imaging radar system was launched aboard the NASA Space Shuttle twice in 1994. This particular image was taken on the second of those flights. "North" is to the upper left. At the center-right portion of the image, the two forks of the Two Rivers join, directing their waters westward then into the northward-flowing Red River of the North. Further north on this image, the Red River joins with the eastward-flowing Pembina River at Pembina, N.D.