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Seasat〔(【引用サイトリンク】url=http://www.jpl.nasa.gov/missions/search.php?q=seasat&img_search_submit.x=43&img_search_submit.y=14 )〕 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〔http://science.nasa.gov/missions/seasat-1/〕 into a nearly circular 800 km orbit with an inclination of 108°. Seasat operated for 106 〔(【引用サイトリンク】url=http://www3.jpl.nasa.gov/missions/past/seasat.html )〕 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 SAR support structure was designed and manufactured by (Northrop Grumman Astro Aerospace ) in Carpinteria, CA. The structure deployed on orbit. 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. ==Seasat SAR data released in 2013== On the 35th anniversary of Seasat's launch, the Alaska Satellite Facility released newly digitized Seasat synthetic aperture radar (SAR) imagery.〔(【引用サイトリンク】url=http://www.jpl.nasa.gov/news/news.php?release=2013-208 )〕 Until this release, Seasat SAR data were archived on magnetic tapes, and images processed from the tapes were available only as optical images of film strips or scanned digital images. Neither the tapes nor the film allow the quantitative analysis possible with the new digital archive.〔(【引用サイトリンク】url=https://www-prod.asf.alaska.edu/seasat/ )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Seasat」の詳細全文を読む スポンサード リンク
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