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Shuttle Imaging Radar-A (SIR-A)

NSSDCA ID: 1981-111A-01

Mission Name: STS 2/OSTA 1
Principal Investigator:Dr. Charles Elachi


The prime objective of Shuttle Imaging Radar-A (SIR-A) was to obtain maplike images of the earth's surface for geologic exploration. The SIR-A experiment used a sidelooking, synthetic aperture radar operating at L-band (1.278 GHz) with a viewing angle of 47 deg to create two dimensional images of the earth's surface. The imaging radar was independent of sunlight and was able to penetrate cloud cover. A swath width of 50 km and a resolution of 40 m both across and along the track of the beam was attained by this system. The sensor was in operation for 8 h during the 2-1/2 day flight, acquiring images of about 10 million sq km between 38 deg N and 38 deg S latitude. Radar imagery recorded differences in surface roughness and terrain attitude and thus was used to delineate such geological features as faults, anticlines, folds and domes, drainage patterns, and stratification. Landsat multispectral imagery was used to provide supplementary information necessary to identify rock types and types of vegetation. For more detailed descriptions, see "Shuttle Imaging Radar-A (SIR-A) Experiment," JPL 82-77, NASA-JPL, and C. Elachi, et al., "Shuttle Imaging Radar Experiment," Science, v. 218, n. 4576, pp. 996-1003, 1982.

Alternate Names

  • SIR-A


  • Earth Science: Land Surface Processes
  • Earth Science: Physical Oceanography
  • Earth Science: Land Topography

Additional Information

Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office



NameRoleOriginal AffiliationE-mail
Dr. R. Stephen SaundersOther InvestigatorNASA Jet Propulsion Laboratory
Mr. Walter E. Brown, Jr.Other InvestigatorNASA Jet Propulsion Laboratory
Dr. Gerald G. SchaberOther InvestigatorUS Geological
Dr. Louis F. DellwigOther InvestigatorUniversity of Kansas
Dr. Anthony W. EnglandOther InvestigatorNASA Johnson Space Center
Dr. M. GuyOther InvestigatorCentre National d'Etudes Spatiales
Dr. Harold C. MacDonaldOther InvestigatorUniversity of Arkansas
Dr. Charles ElachiPrincipal InvestigatorNASA Jet Propulsion
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