|
The Landsat program is the longest running enterprise for acquisition of satellite imagery of Earth. On July 23, 1972 the Earth Resources Technology Satellite was launched. This was eventually renamed to Landsat. The most recent, Landsat 8, was launched on February 11, 2013. The instruments on the Landsat satellites have acquired millions of images. The images, archived in the United States and at Landsat receiving stations around the world, are a unique resource for global change research and applications in agriculture, cartography, geology, forestry, regional planning, surveillance and education, and can be viewed through the USGS 'EarthExplorer' website. Landsat 7 data has eight spectral bands with spatial resolutions ranging from 15 to 60 meters; the temporal resolution is 16 days.〔(The Landsat Program - Technical Details )〕 ==History== Hughes Santa Barbara Research Center initiated designed and fabricated the first three Multispectral Scanners (MSS) in the same year man landed on the moon, 1969. The first prototype MSS was completed within nine months by fall of 1970 when it was tested by scanning Half Dome at Yosemite National Park. The program was called the Earth Resources Technology Satellites Program when it was initiated in 1966, but the name was changed to Landsat in 1975. In 1979, (Presidential Directive 54 ) under President of the United States Jimmy Carter transferred Landsat operations from NASA to NOAA, recommended development of long term operational system with four additional satellites beyond Landsat 3, and recommended transition to private sector operation of Landsat. This occurred in 1985 when the Earth Observation Satellite Company (EOSAT), a partnership of Hughes Aircraft and RCA, was selected by NOAA to operate the Landsat system under a ten year contract. EOSAT operated Landsats 4 and 5, had exclusive rights to market Landsat data, and was to build Landsats 6 and 7. In 1989, this transition had not been fully completed when NOAA's funding for the Landsat program was due to run out (NOAA had not requested any funding, and Congress had appropriated only six months of funding for the fiscal year) and NOAA directed that Landsats 4 and 5 be shut down.〔 〕 The head of the newly formed National Space Council, Vice President Dan Quayle, noted the situation and arranged emergency funding that allowed the program to continue with the data archives intact. 〔〔〔 〕 Again in 1990 and 1991, Congress provided only half of the year's funding to NOAA, requesting that agencies that used Landsat data provide the funding for the other six months of the upcoming year.〔 In 1992, various efforts were made to procure funding for follow on Landsats and continued operations, but by the end of the year EOSAT ceased processing Landsat data. Landsat 6 was finally launched on October 5, 1993, but was lost in a launch failure. Processing of Landsat 4 and 5 data was resumed by EOSAT in 1994. NASA finally launched Landsat 7 on April 15, 1999. The value of the Landsat program was recognized by Congress in October 1992 when it passed the Land Remote Sensing Policy Act (Public Law 102-555) authorizing the procurement of Landsat 7 and assuring the continued availability of Landsat digital data and images, at the lowest possible cost, to traditional and new users of the data. 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「Landsat program」の詳細全文を読む スポンサード リンク
|