Each month in “Slice of History” we feature a historical photo from the JPL Archives. See more historical photos and explore the JPL Archives at https://beacon.jpl.nasa.gov/.
The Seasat project was a feasibility demonstration of the use of orbital remote sensing for global observation. It was launched on June 26, 1978 and carried five sensors:
– The Radar Altimeter (ALT) measured wave height at the subsatellite point and the altitude between the spacecraft and the ocean surface. The altitude measurement was precise to within ±10 cm (4 in.). The altitude measurement, when combined with accurate orbit determination information, produced an accurate image of the sea surface topography.
– The Seasat (Fan-Beam) Scatterometer System (SASS) measured sea surface wind speeds and directions at close intervals from which vector wind fields could be derived on a global basis.
– The Scanning Multichannel Microwave Radiometer (SMRR) measured wind speed, sea surface temperature to an accuracy of ±2°C, and atmospheric water vapor and liquid water content.
– The Synthetic Aperture Radar (SAR) was an imaging radar that provided images of the ocean surface from which could be determined ocean wave patterns, water and land interaction data in coastal regions, and radar imagery of sea and fresh water ice and snow cover.
– The Visual and Infrared Radiometer (VIRR) objective was to provide low-resolution images of visual and infrared radiation emissions from ocean, coastal and atmospheric features in support of the microwave sensors. Clear air temperatures were also measured.
This 1978 illustration was based on a painting, probably by artist Ken Hodges. He created artwork for many different Jet Propulsion Laboratory missions in the 1970s and 1980s, before computer aided animation was used for mission presentations and outreach.