History and Features of Landsat 7

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History and Features of Landsat 7

• By Andy Vogelsberg

Photo of Landsat 7 taken from http//teacherlink.e
d.usu.edu/tlnasa/pictures/litho/landsat/land.jpg
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History of Landsat Program

• The Landsat program was inspired by Apollo moon
  bound missions.
• William Pecora proposed the idea of having remote
  sensing satellites in space in 1964.
• Eight years later, his proposal became reality,
  and the Landsat program had begun.
• Landsat 1 was launched on July 23, 1972. Since
  then, six other satellites have been launched.
• Landsat 7 is the most recent satellite we have
  launched, providing us the most technological
  data possible.

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Landsat 7

• Landsat 7 was launched on April 15, 1999 from
  Vandenberg Air Force Base in California and was
  built to last at least 5 years.
• The purpose of Landsat 7 is to replicate the
  capabilities of other launches, as well as
  provide new information.
• Landsat 7 can provide more information than any
  of the previous Landsat satellites at a lower
  cost.
• 532 images a day can be produced by Landsat 7.
• Landsat 7 orbits the earth at an altitude of 705
  Kilometers and covers a swath width of 185 km.
• The satellite covers the whole earth in 15 days
  or 232 orbits.
• Landsat 7 weighs 1973 kg.
• The observing instrument on board Landsat 7 is
  the Enhanced Thematic Mapper Plus (ETM).

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Enhanced Thematic Mapper Plus(ETM)

• The ETM was also used on Landsats 4 and 5.
• Landsat 7s ETM has features that other
  satellites did not.
• These features make Landsat 7 a more useful
  component for studies in global change,
  monitoring of land cover, and mapping large
  areas.

Image of Landsat 7 ETM taken from http//landsa
t.usgs.gov/project_facts/history/images/ETMinstru
ment.jpg
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Components of Landsat 7
A drawing of Landsat 7 taken from
http//directory.eoportal.org/images/LS7_Auto4.jp
eg
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Advantages of Landsat 7s ETM

• Landsat 7s ETM is different from previous
  thematic mappers because it offers
• a panchromatic band with 15m spatial resolution
• on-board, full aperture, 5 absolute radiometric
  calibration
• a thermal IR channel with 60m spatial resolution
• an on-board data recorder
• (Bulleted data taken directly from
  http//landsat.gsfc.nasa.gov/about/landsat7.html)

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Malfunction on Landsat 7

• On May 31, 2003 Landsat 7 experienced its first
  problems.
• The Scan Line Protector (SLC) on board Landsat 7
  failed. The problem created narrow bands on
  images formed by Landsat 7 to be missing.
• These narrow bands were caused because image
  scanning in the SLC was at an angle instead of
  being parallel.
• To this day, the malfunction of the SLC is still
  affecting images acquired by the satellite.
• Landsat 7 loses approximately 22 on each image
  it acquires because the SLC is not operable.
• Methods are being done by the USGS to duplicate
  all missing data due to the malfunction of the
  SLC.

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Affects of No SLC

• The SLCs job was to compensate for the forward
  motion of Landsat 7.
• Without it, a zig zag motion is created. (bottom
  left)
• The photo on the right shows the affected area
  created without no SLC.

Images taken from http//landsat.usgs.gov/data_pro
ducts/slc_off_data_products/slc_off_background.php

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Major Advantages of Landsat 7

• Landsat 7 continues to give us high-quality data
  with the ETM which dates back to Landsat 4 in
  1982. Since data looks similar, global change is
  easy to detect from pre-existing archives.
• Data acquisition is optimum, because Landsat 7
  takes all photos in sun lit conditions.
  Information from NOAA is also used to keep images
  cloud cover minimal.
• Landsat 7 can obtain and store more data faster
  than any other form of remote sensing instrument.
  
• The data collected by the satellite is easy to
  get through the USGS or EROS at an affordable
  price.
• The Landsat 7's ETM has been called "the most
  stable, best characterized Earth observation
  instrument ever placed in orbit."
• (Taken from http//landsat.gsfc.nasa.gov/
  about/landsat7.html)
• Landsat 7s ETM has also set the standard on
  accuracy for all other remote sensing systems.
  The ground accuracy acquired through Landsat 7s
  data is second to none.

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Controllers of Landsat 7

• The Flight Operations Team (FOT) is in charge of
  command control as well as telemetry operations
  for Landsat 7.
• All controls of the sattelite take place in the
  Mission Operation Center in the Goddard Space
  Flight Center which is located in Greenbelt
  Maryland.
• Data is captured from the sattelite in both Sioux
  Falls SD, as well as Alice Springs Australia.
• Backup sites are also located in Poker Flat
  Alaska and Svalbard Norway.

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Mission Operations Center
http//ls7pm3.gsfc.nasa.gov/mainpage.html
http//ls7pm3.gsfc.nasa.gov/mainpage.html
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Images Taken by Landsat 7
Top Left Cap Canaveral Launching Site Middle
Flooding in South Africa Top Right Flooding in
New Orleans due to Hurricane Katrina
medias.obs-mip.fr/.../en/systemes/landsat.html
landsat.usgs.gov/gallery/detail/411/
gisdata.usgs.net/.../categories.asp?catid10
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Composite Images of Landsat 7

• Left Image True Color Composite (Bands 321)
• Middle Image Near Infrared Composite (Bands 432)
• Right Image Short-wave Infrared Composite (Bands
  742)

chesapeake.towson.edu/data/all_composite.asp
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References

• National Aeronautics and Space Administration,
  Landsat 7, World Wide Web URL http//landsat.gsfc
  .nasa.gov/about/landsat7.html
• Wikipedia, The Free Encyclopedia, Landsat 7,
  World Wide Web URL http//en.wikipedia.org/wik
  i/Landsat_7
• National Aeronautics and Space Administration,
  Landsat 7 Science Data Users Handbook, World Wide
  Web URL http//landsathandbook.gsfc.nasa.gov/hand
  book.html
• National Aeronautics and Space Administration,
  SLC-off Products Background, World Wide Web URL
  http//landsat.usgs.gov/data_products/slc_off_dat
  a_products/slc_off_background.php
• Landsat 7, Supplying data users worldwide with
  low cost, multi-purpose, land remote sensing data
  into the next century, World Wide Web URL
  http//geo.arc.nasa.gov/sge/landsat/l7.html
• Landsat 7 Home Page, World Wide Web URL
  http//ls7pm3.gsfc.nasa.gov/mainpage.html