History and Features of Landsat 7

Report
History and Features of
Landsat 7
By: Andy Vogelsberg
Photo of Landsat 7 taken from
http://teacherlink.ed.usu.edu/tlnasa/pic
tures/litho/landsat/land.jpg
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.
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+).
Enhanced Thematic Mapper Plus
(ETM+)

The ETM+ was also used on Landsats 4 and 5.

Landsat 7’s 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://landsat.usgs.gov/project_facts/history/images/ETM+instrument.jpg
Components of Landsat 7
A drawing of Landsat 7 taken from:
http://directory.eoportal.org/images/LS7_Auto4.jpeg
Advantages of Landsat 7’s ETM+
Landsat 7’s 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)
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.
Affects of No SLC

The SLC’s 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_products/slc_off_data_products/slc_off_background.php
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 7’s ETM+ has also set the standard on accuracy for all other remote
sensing systems. The ground accuracy acquired through Landsat 7’s data is second
to none.
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.
Mission Operations Center
http://ls7pm3.gsfc.nasa.gov/mainpage.html
http://ls7pm3.gsfc.nasa.gov/mainpage.html
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?catid=10
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
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/wiki/Landsat_7

National Aeronautics and Space Administration, Landsat 7 Science Data Users
Handbook, World Wide Web URL:
http://landsathandbook.gsfc.nasa.gov/handbook.html

National Aeronautics and Space Administration, SLC-off Products: Background, World
Wide Web URL:
http://landsat.usgs.gov/data_products/slc_off_data_products/slc_off_background.p
hp

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

similar documents