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Seasat 1 was the first Earth-orbiting satellite specifically designed and tasked for the remote sensing of Earth's oceans. Seasat carried a payload of five scientific instruments that enabled measurements of sea surface wind velocity, land and sea surface topography, ocean surface salinity, ocean surface gravity waves, land and sea ice, and sea surface temperature. 

Seasat 1 was in continuous operation for 106 days and served as the precursor to many of NASA's later missions including Nimbus-7, TOPEX/Poseidon, NASA Scatterometer (NSCAT), QuikSCAT, Jason-1, OSTM/Jason-2, and the synthetic aperture radars (SARs) that flew aboard NASA's many Space Shuttle missions.

Learn more about Seasat 1

Data

10 Datasets
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Type

Earth Observation Satellite

Objective

Test oceanographic sensors and monitor Earth's seas

Launch

June 26, 1978

Data Center

PO.DAAC
ASF DAAC
  • Synthetic Aperture Radar (SAR)
  • Radar altimeter
  • SEASAT-A Satellite Scatterometer (SASS)
  • Visible and Infrared Radiometer (VIRR)
  • Scanning Multichannel Microwave Radiometer (SMMR)

Seasat 1 did not have an onboard recording capability for data. Received SAR echoes were downlinked in real-time to five ground receiving stations: Goldstone, California; Fairbanks, Alaska; Merritt Island, Florida; Shoe Cove, Newfoundland; and Oakhanger, United Kingdom. The SAR data were transmitted from the satellite to the ground stations in a 20 MHz analog data stream.

Seasat 1 SAR Instrument ParemeterValue
PolarizationHH
Look DirectionRight
Footprint100 km x 15 km
Image Frame Size100 km x 100 km
Image Resolution25 m
Number of Looks4
Bandwidth19 MHz
Slant Range Resolution6.6 m
Ground Range Resolution17-23 m (based on incidence angle)
Frequency1275 MHz (L-Band)
Radar Wavelength23.5 cm
Pulse Duration33.8 microseconds
Sampling Rate45.53 MHz
Sampling Time21.97 nS
Sampling Window Duration288 microseconds
Incidence Angle23° ± 3°
Pulse Repetition Frequency1647 Hz
Data Sample Size5-bits

Originally, Seasat 1 SAR data were optically processed into survey data products available on 70 mm film. Approximately 10% of the total Seasat 1 SAR dataset was digitally processed by NASA’s Jet Propulsion Laboratory (JPL) from 1978 and 1982. Those digitally processed products contained complete 100-km-wide swaths of data.

The processing of the swath files into data products is carried out with the Alaska Satellite Facility (ASF) Seasat Processing System (ASPS). ASPS uses the modified version of the NASA Jet Propulsion Laboratory (JPL) repeat orbit interferometry (ROI) package to generate single look complex (SLC) images that are converted with ASF tools to the final detected ground range HDF5 products. The naming convention of the products follows:

SS_ooooo_STD_Fffff

where ooooo is the five digit orbit number of the Seasat satellite at the time of imaging and ffff is the four digit ESA (European Space Agency) frame number scheme, modified to create images 100 km x 100 km in size.

The Seasat data product packages are distributed in two different formats: HDF5 and GeoTIFF. The files that are common to both packages, provided in compressed .zip format, are the following:

  • Browse image: SS_ooooo_STD_Fffff .jpg
  • ISO XML metadata: SS_ooooo_STD_Fffff.iso.xml
  • XML metadata: SS_ooooo_STD_Fffff.xml
  • KML coverage file: SS_ooooo_STD_Fffff.kml
  • Data quality report: SS_ooooo_STD_Fffff.qc_report

Citing Seasat Data and Crediting Seasat Imagery

Type of DatasetGuidanceFormatExample
Seasat 1 DataCite data in publications such as journal papers, articles, presentations, posters, and websites. Please send copies of, or links to, published works citing data, imagery, or tools accessed through the Alaska Satellite Facility (ASF) to uso@asf.alaska.edu with "New Publication" in the subject line.Seasat data 1978 (NASA). Processed by NASA's ASF DAAC 2013. Retrieved from NASA's ASF DAAC [add URL if print publication: asf.alaska.edu] [month day year of data access].Dataset: UAVSAR, NASA 2011. Retrieved from NASA's ASF DAAC June 7, 2015.
Seasat 1 ImageryInclude appropriate credit with each image shown in publications such as journal papers, articles, presentations, posters, and websites. For more information, see NASA guidelines.Seasat data 1978 (NASA). Processed by NASA's ASF DAAC 2013. Retrieved from NASA's ASF DAAC [day month year of access].Credit: NASA 1978, processed by NASA's ASF DAAC 2013.

Instruments Aboard Seasat 1

Instrument Name Operational Date(s) Spectral Resolution Type of Instrument
Scanning Multichannel Microwave Radiometer (SMMR) 1978-1987

10-channel (five-frequency dual polarized) scanning radiometer operating at 0.8-, 1.4-, 1.7-, 2.8-, and 4.6-cm wavelengths (37, 21, 18, 10.7, and 6.6 GHz)

 Spectrometers/Radiometers

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