SEASAT
SEASAT was the first Earth-orbiting satellite designed for remote sensing of the Earth's oceans and had on board the first spaceborne synthetic aperture radar (SAR). The mission was designed to demonstrate the feasibility of global satellite monitoring of oceanographic phenomena and to help determine the requirements for an operational ocean remote sensing satellite system. Specific objectives were to collect data on sea-surface winds, sea-surface temperatures, wave heights, internal waves, atmospheric water, sea ice features and ocean topography. SEASAT was managed by NASA's Jet Propulsion Laboratory and was launched on 27 June 1978[1] into a nearly circular 800 km orbit with an inclination of 108°. SEASAT operated for 105 days until 10 October 1978, when a massive short circuit in the satellite's electrical system ended the mission.
SEASAT carried five major instruments designed to return the maximum information from ocean surfaces:
- Radar altimeter to measure spacecraft height above the ocean surface
- Microwave scatterometer to measure wind speed and direction
- Scanning multichannel microwave radiometer to measure sea surface temperature
- Visible and infrared radiometer to identify cloud, land and water features
- Synthetic Aperture Radar (SAR) L-band, HH polarization, fixed look angle to monitor the global surface wave field and polar sea ice conditions {the antenna is the light parallelogram in the picture}
Many later remote sensing missions owe their legacy to SEASAT. These include imaging radars flown on NASA's Space Shuttle, altimeters on Earth-orbiting satellites such as TOPEX/Poseidon, and scatterometers on NASA Scatterometer (NSCAT), QuikSCAT, and Jason 1.
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[edit] Conspiracy theory
SEASAT was able to detect the wakes of submerged submarines, a discovery not anticipated before launch.[2] The conspiracy theory holds that once this was discovered, the military shut SEASAT down, with a cover story of a power supply short.[3][4]
[edit] See also
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[edit] References
- ^ http://science.nasa.gov/missions/seasat-1/
- ^ WILLIAM J. BROAD (11 May 1999). "U.S. Loses Hold on Submarine-Exposing Radar Technique". New York Times.
- ^ Pat Norris (2008). Spies in the Sky Surveillance Satellites in War and Peace. Praxis. doi:10.1007/978-0-387-71673-2. ISBN 978-0-387-71672-5. p. 172
- ^ "The Ship Model Forum". Retrieved 2008-11-18.
Science, vol. 204, No. 4400, 29 June 1979, cover and papers pp. 1405–1424.
IEEE Journal on Oceanic Engineering, vol. OE-5, no. 2, April 1980, Special Issue on SEASAT-1 Sensors.
Charles Elachi, "Spaceborne Imaging Radar: Geologic and Oceanographic Applications," Science, vol. 209, No. 4461, 5 September 1980, pp. 1073–1082.
[edit] External links
- JPL SEASAT page
- Seasat Views Ocean and Sea Ice with Synthetic Aperture Radar
- SEASAT II, JSR-83-203, March 1984
- SEASAT III & IV, JSR-84-203, August 1984
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