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As the longest running commercial satellite imagery program, administered by the United States Geological Survey (USGS) and NASA, Landsat provides extensive coverage of medium resolution imagery, both historical and current. Landsat imagery is an excellent tool for analysis and applications covering large geographic areas over a longer period of time. LANDSAT-1 was the world's first earth observation satellite (EOS), launched by the United States in 1972. It is recognized for its ability to observe the earth far from space. Its excellent set of capabilities emphasized the importance of state-of-the-art remote sensing. Following LANDSAT-1, LANDSAT-2, 3, 4, 5, and 7 were launched. LANDSAT-7 is currently operated as a primary satellite. LANDSAT-5 was equipped with a multispectral scanner (MSS) and thematic mapper (TM). MSS is an optical sensor designed to observe solar radiation, which is reflected from the Earth's surface in four different spectral bands, using a combination of the optical system and the sensor. TM is a more advanced version of the observation equipment used in the MSS, which observes the Earth's surface in seven spectral bands that range from visible to thermal infrared regions. The LANDSAT-7 satellite was successfully launched from Vandenburg Air Force Base on April 15, 1999. LANDSAT-7 is a 5,000 pound-class satellite, designed for a 705 km, sun-synchronous, earth mapping orbit with a 16-day repeat cycle. The payload is a single nadir-pointing instrument, the Enhanced Thematic Mapper Plus (ETM+). S-Band is used for commanding and housekeeping telemetry operations, while X-Band is used for instrument data downlink. A 378 gigabit solid state recorder (SSR) can hold 42 minutes of instrument data and 29 hours of housekeeping telemetry concurrently. Basic characteristics: | Mode: | VNIR | SWIR | TIR | PAN | | Spectral bands (mkm): | blue: 0.45-0.52 green: 0.53-0.61 red: 0.63-0.69 near IR: 0.78-0.90 | middle IR: 1.55-1.75 middle IR: 2.09-2.35 | thermal IR: 10.40-12.50 | 0,52-0,90 | | Spatial resolution: | 30 m | 30 m | 60 m | 15 m | | Data transmission rate: | 150 Mbits/sec | | Swatch Width: | 185 km | | Radiometric resolution: | 8 bits per pixel | | Revisit time: | 16 days | | Stereo imagery | n/a |
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