![]() ![]() These ancient river channels, invisible to the human eye beneath the deep, dry sand of the Sahara Desert, were revealed for the first time by SIR-C/X-SAR instruments during their second shuttle flight in October 1994.ĭataset proved immediately useful, revealing, for instance, ancient riverbeds beneath Successive observations - like the gradual creep of an earthquake fault or the And it can reveal even minute changes in the target between Combining views, interferometry createsĭetailed, 3D topographical images of a target at the moment of simultaneous Slightly offset passes over the same terrain were essential for theĭata-processing technique of interferometry. ![]() ![]() Steering" that allowed them to "see" to either side of what was The C- and L-band antennas were fixed at a particular angle, but they had "electronic And they did this flying upside down, since the cargo bay holding the To observe the same supersites during both flights and to makeĬonsistent daily passes over them, the shuttle crew used sophisticatedĪlgorithms to navigate the spacecraft in precise orbits as close as 10 metersĪpart. To capture changes over time that's why it flew on shuttle flights six monthsĪpart. Out the scattering of radar waves to distinguish, for example, vegetated from unvegetated Using this "fully polarized" data, scientists can separate The C- and L-bandĪntennas could send and receive waves of both horizontal and vertical Ground) or vertical (in a plane perpendicular to the ground). Radio frequency waves can be either horizontal (in a wavy plane parallel to the Multiple frequencies, some observations were made in multiple "polarizations." Leap from black-and-white to color film, allowed the mission to collect data inĭifferent scales, providing a crisp snapshot of each targeted feature, Into a massive, 12-by-4-meter, 11.5-ton structure. Three frequencies - C-, L- and X-band - using three adjacent antennas combined SIR-C/X-SAR, neither predecessor made radar observations simultaneously in Indeed, SIR-C's predecessors, SIR-A and SIR-B, were synthetic The larger the aperture, the greater the image The movements of a host airplane or spacecraft to "synthesize" an "aperture" Radar - in darkness, under cloud cover or vegetation, even underground - using To unpack that sizable trunk of terminology, let's start with "syntheticĪperture radar": Since the late 1970s, NASA has been imaging Earth with Known as simultaneous multifrequency, fully polarized, repeat-pass interferometric Of Earth has never been the same since SIR-C/X-SAR's demonstration of what's "DLR's TerraSAR-X and TanDEM-X missions have since Radar Topography Mission, which mapped 80% of the Earth in 2000," said Tonyįreeman, now manager of JPL's Innovation Foundry, who led end-to-endĬalibration of SIR-C. "The many innovationsof SIR-C/X-SAR have been used in virtuallyĮvery air- and spaceborne radar mission since, starting with NASA's Shuttle It also imaged events occurring during the flights, such as areas of scientific interest in such locations as the Sahara, Brazil, the AlpsĪnd the Gulf Stream. October 1994, the radar system made multiple passes over 19 "supersites" Of orbits on two flights aboard the Space Shuttle Endeavour, in April and Most advanced imaging radar system ever used in air or space. The X-SAR instrument, built by the German Aerospace Center (DLR), constituted the Instrument, built by NASA'S Jet Propulsion Laborator in Pasadena, California, and To inform decisions to slow and mitigate climate change. Mission made available to people worldwide the scientific data used to this day The Spaceborne Imaging Radar-C and X-Band Synthetic Aperture Radar (SIR-C/X-SAR) Way we use radar to observe large-scale environmental processes on our home Marks the 25th anniversary of the end of a space mission that transformed the ![]()
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