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Landsat TM
U.S. Geological Survey, no re-distribution restrictions
No on-demand acquisition request procedures exist. Both USGS Center for Earth Resources Observation and Science (EROS) and the International Cooperators (of which there are 13) acquire approved land mass within their respective antenna acquisition zones. Global coverage is not possible due to lack of on-board data storage and due to failure of the Tracking and Data Relay Satellite System (TDRSS) transmitter. Requests for archived data can be made to EROS and any licensed ground station operator. A new USGS policy went into effect in December 2008 that made the entire US Landsat archive freely available.
Satellite Instruments
The multi-spectral Thematic Mapper (TM) whisk-broom instrument was developed and successfully launched as the primary payload by NASA on the Landsat 4 and 5 satellites. The launch dates for Landsat 4 and 5 were July 16, 1982 and March 1, 1984, respectfully. General Electric (now Lockheed-Martin) built the spacecraft and the TM instruments were designed and manufactured by Santa Barbara Research Center (SBRC). 3 visible bands (30m), 2 NIR (30m), 1 MIR (30m), 1 Thermal (120m)
Rachel Headley
U.S. Geological Survey
USGS EROS Sioux Falls, SD 57198
Kristi Kline
U.S. Geological Survey
USGS EROS Sioux Falls, SD 57198
Measurment TypeVisible/IR-imager
Platform TypeLandsat TM
OrbitSun synchronous
Spectral Coverage
Scan PatternCross track
Repeat Time16 days
Wavelength0.45 to 12.5um
Number of Bands7
Start DateMar 1984
Temporal Coverage
Swath Width185 km
Resolution 130m
Resolution 2120m
Landsat 4 was decommissioned in June 2001 after being in standby mode [all of the traveling wave tube amplifiers (TWTAs) failed] since December of 1993. Landsat 5, launched in March 1984 by NASA, was designed to last three years, but as of this writing (Sept. ’07), over 23 years since launch, the spacecraft and instrument are still functioning, but with some reduced capabilities. To date, USGS EROS has received and archived approximately 700,000 Landsat 5 scenes, with additional accumulations totaling 6,000 scenes per month. This figure does not include the archive count for the International Cooperators. Landsat 5 has not been problem free, however. In 1987 its TDRSS transmitter failed resulting in the inability to downlink back to the U.S. data that were collected outside the U.S. antenna’s acquisition circle. In 2005 both the primary and redundant solar array drives malfunctioned causing power issues. Over the years, clever flight software engineers have crafted numerous fixes that have permitted continued imaging. In the case of the failed solar array drives, they have managed to maintain adequate battery recharging via fixed array operations requiring special maneuvers each orbit to orient the solar array toward the sun.
23 Oct 2009 11:55