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Designation 10967 / 78064A
Launch date 27 Jun 1978
Country of origin United States
Mission Remote sensing
Perigee/Apogee 761/764 km
Inclination 108°
Period 100.1 min
Launch vehicle Atlas Agena D
Launch site Vandenberg

Seasat was designed to demonstrate techniques for global monitoring of oceanographic phenomena and features, to provide oceanographic data, and to determine key features of an operational ocean-dynamics monitoring system. The major difference between Seasat and previous Earth observation satellites was the use of active and passive microwave sensors to achieve an all-weather capability.

Dedicated ocean monitoring satellite that carried the first spaceborne synthetic aperture radar (SAR) and other microwave instruments.

End of life

Out of service 10 Oct 1978 (106 days of returning data)
Cause a short circuit drained all power from its batteries

Technical data


Prime contractor Lockheed
Platform Agena
Mass at launch 2300 kg
Dimension 1.5 m diameter x 21 m length
Solar array 2 panels,
Stabilization 3 axis (momentum wheel/horizon sensing system)
Design lifetime 2 years

The second stage of the Atlas-Agena launch vehicle served as the satellite bus and provided attitude control, power, guidance, telemetry, and command functions. Attached to the Agena was a sensor module which carried the payload of five microwave instruments and their antennas. Together, the two modules were about 21 meters long with a maximum diameter of 1.5 m without appendages deployed. After burnout of the Agena stage and injection into orbit, Seasat-A weighed 2300 kg. In orbit the satellite appeared to stand on end with the sensor and communications antennas pointing toward Earth and the Agena rocket nozzle and solar panels pointing toward space.

SAR (Synthetic Aperture Radar)

Frequency 1.275 GHz (L-band)
Resolution 25 m
Swath width 100 km

Mission: deep ocean wave pattern imaggery, coastal sea/land interaction, ice and snow imagery

ALT (Radar Altimeter)

Frequency Ku-band
Accuracy 10 cm

Mission: measure satellite altitude above sea surface, significant wave height at sub-satellite point, establish characteristics of marine geoid

SASS (Seasat-A Satellite Scatterometer) - Wind scatterometer

Frequency 1.275 GHz (L-band)
Accuracy windspeed +/- 2 m/s; direction better than 20°

Mission: windspeed and direction

SMMR (Scanning Multichannel Microwave Radiometer) (passive)

Frequencies 6.6, 18, 37, 10.7 & 21 GHz (H & V polarization)
Swath width 600 km
Accuracy ocean surface temperature 2 K
ocean surface windspeed 2 m/s

Mission: ocean surface temperature and windspeed, water vapor, icecover, rain rate, propagation corrections for other instruments

VIRR (Visible and IR Radiometer)

Wavebands 0.25-0.73 µm
10.5-12.5 µm
Field of view 2-5 km
Swath width 1900 km

Mission: image feature identification in support of other instruments, thermal images of ocean

Downlink frequency: 2287.5 MHz

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