Landsat 4

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Landsat 4
Artist's rendering of Landsat 5, which is identical to Landsat 4.
Mission typeEarth imaging
OperatorNASA / NOAA
COSPAR ID1982-072A Edit this at Wikidata
SATCAT no.13367
Spacecraft properties
GE Astro Space
Launch mass1,941 kilograms (4,279 lb)
Dry mass1,407 kilograms (3,102 lb)
Start of mission
Launch dateJuly 16, 1982 (1982-07-16)
Rocket
SLC-2W
End of mission
DeactivatedJune 15, 2001 (2001-06-16)
Orbital parameters
Reference systemGeocentric
RegimeSun-synchronous
Perigee altitude700 kilometers (430 mi)
Apogee altitude704 kilometers (437 mi)
Inclination98.2 degrees
Period98.81 minutes
Repeat interval16 days
EpochAugust 17, 1982[1]
 

Landsat 4 is the fourth satellite of the Landsat program. It was launched on July 16, 1982, with the primary goal of providing a global archive of satellite imagery. Although the Landsat Program is managed by NASA, data from Landsat 4 was collected and distributed by the U.S. Geological Survey. Landsat 4 science operations ended on December 14, 1993, when the satellite lost its ability to transmit science data, far beyond its designed life expectancy of five years. The satellite housekeeping telemetry and tracking continued to be maintained by NASA until it was decommissioned on June 15, 2001.

Background

NOAA.[7]

The second generation of Landsat, Landsat 4 and 5, flew in lower orbits than the first three missions. Although they were in lower orbits, they had a higher field of view (FOV) so they had the same swath widths. The new Landsat spacecraft also featured improved instrumentation.[8]

Satellite design

Operation

The spacecraft was built by

Fairchild Industries.[8][9]

The satellite was designed to be fixed by astronauts in space via the Space Shuttle, or taken back to Earth for repairs. It was expected that the shuttles would be able to reach Landsat's relatively far orbit by 1985.[7]

Landsat 4's

solar array produced 1430 W of power.[8] The satellite weighed 4,300 pounds (2,000 kg). Landsat 4 was designed to last a minimum of three years.[10]

The satellite communicated to the ground with a direct downlink with the Tracking and Data Relay Satellite System (TDRSS) at 85 Mbit/s on the

Ku-bands. The high gain antenna was extended with a retractable boom.[8] The data used 8 bit quantization.[10]

Sensors

Landsat 4 carried an updated

Hughes Aircraft.[9]

Landsat 4 was the first satellite in the Landsat program to incorporate the

X-band transmitter to modernized ground antennas.[8]

Mission

Launch

The satellite was launched from

Vandenberg Air Force Base in California on July 16, 1982, on a Delta 3920.[10][11] Landsat 4 was placed into a north–south near polar orbit,[7] approximately 700 kilometers (430 mi) above Earth's surface, and circling the globe every 99 minutes.[10]

Operations

1/4 scale model on display at the National Air and Space Museum in Washington DC

The first major malfunction occurred July 27, 1982. The high gain Ku antenna was commanded to deploy but failed. Attempts to free the antenna were successful on August 15.[8]

In February 1983, the satellite lost half of its solar power and the ability to send science data directly to Earth, prompting fears the satellite would fail sooner than expected.[12] This caused the early launch of Landsat 5, a satellite that was identical in specification to Landsat 4. After the issue was identified in Landsat 4, modifications were made to Landsat 5 to prevent the same issue from occurring.[12]

Landsat 4 was able to resume science operations when the

S-band, until the satellite was decommissioned June 15, 2001.[10][14]

Space Shuttle service mission

As early as 1982, a mission was in the planning stages to retrieve Landsat 4 for servicing back on Earth. The 1982 edition of the STS Flight Assignment Manifest scheduled the second

Challenger disaster
.

References

  1. ^ McDowell, Jonathan. "Satellite Catalog". Jonathan's Space Page. Retrieved June 16, 2013.
  2. ^ a b "Landsat-1 to Landsat-3". eoPortal Directory. Retrieved June 30, 2017.
  3. Newspapers.com. Free access icon
  4. ^ "Landsat 2 History". Landsat Missions. Archived from the original on April 28, 2016. Retrieved October 5, 2018.
  5. ^ "Landsat 3 Launch Information". NASA Space Science Data Coordinated Archive. NASA. March 5, 1978. Retrieved July 9, 2017.
  6. ^ United States Geological Survey (August 9, 2006). "Landsat 3 History". Archived from the original on April 12, 2016. Retrieved June 29, 2017.
  7. ^ a b c Rossiter, Al (July 14, 1982). "NASA to Launch New Earth Monitor". The Noblesville Ledger – via Newspapers.com.
  8. ^ a b c d e f g "Landsat-4 and Landsat-5". eoPortal Directory. Retrieved March 10, 2018.
  9. ^ a b Rumerman, Judy A. (1999). "NASA Historical Data Books" (PDF). The NASA History Series. NASA Historical Office. p. 123.
  10. ^ a b c d e f g "Landsat 4 History". USGS. Archived from the original on September 18, 2017. Retrieved March 7, 2018.
  11. ^ "New EROS satellite launched successfully". Argus-Leader. July 17, 1982 – via Newspapers.com.
  12. ^ a b "Sub Landsat to Monitor Crops". The Daily Spectrum. January 17, 1984. p. 13 – via Newspapers.com.
  13. ^ "The Landsat Program – History – Landsat 4". National Aeronautics and Space Administration. Archived from the original on August 21, 2010.
  14. ^ "Landsat 4". NASA. Archived from the original on June 16, 2008.

External links

Retrieved from "https://en.wikipedia.org/w/index.php?title=Landsat_4&oldid=1174983910"