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Landsat 4 was launched from Vandenberg Air Force Base in California on July 16, 1982 on a Delta 3920 rocket. With an updated design than the previous three missions, the satellite carried the Multispectral Scanner (MSS) as well as the new Thematic Mapper (TM) instruments. The sensors onboard the satellite collected data until late 1993, and the satellite was decommisioned on June 15, 2001.
Like previous missions, the Landsat 4 satellite orbited the the Earth in a sun-synchronous, near-polar orbit, but flew at a lower altitude of 705 km (438 mi), inclined at 98.2 degrees, and circled the Earth every 99 minutes. The satellite had a 16-day repeat cycle with an equatorial crossing time: 9:45 a.m. +/- 15 minutes. Although the satellite was in a lower orbit, it had a higher field of view (FOV) to retain the same swath width of 185 km (115 miles).
The lower altitude results in a different swathing pattern, and Landsat 4 data were acquired on the Worldwide Reference System-2 (WRS-2) path/row system, with swath overlap (or sidelap) varying from 7 percent at the Equator to a maximum of approximately 85 percent at extreme latitudes.
Landsat 4 was built and launched by NASA, NOAA initially oversaw the operations of the satellite. Landsat 4 operations were contracted out to the Earth Observation Satellite Company (EOSAT) corporation in 1984.
Landsat 4 Instruments
Landsat 4 carried the Multispectral Scanner (MSS) and the new Thematic Mapper (TM) sensors.
Multispectral Scanner (MSS)
The MSS sensor on Landsat 4 was identical to Landsats 1, 2 and 3.
- Four spectral bands:
- Band 4 Visible (0.5 to 0.6 µm)
- Band 5 Visible (0.6 to 0.7 µm)
- Band 6 Near-Infrared (0.7 to 0.8 µm)
- Band 7 Near-Infrared (0.8 to 1.1 µm)
- Data: 100 kHz digital
- Six detectors for each reflective band provided six scan lines on each active scan
- Ground Sampling Interval (pixel size): 57 x 79 m
- Swath width: 185 km (115 miles)
More information about MSS data can be found on https://lta.cr.usgs.gov/MSS.
Thematic Mapper (TM)
The TM's improved spectral and spatial resolution allowed the instrument to see the ground in greater detail and included a thermal band.
- Added the mid-range infrared to the data
- Seven spectral bands, including a thermal band:
- Band 1 Visible (0.45 - 0.52 µm) 30 m
- Band 2 Visible (0.52 - 0.60 µm) 30 m
- Band 3 Visible (0.63 - 0.69 µm) 30 m
- Band 4 Near-Infrared (0.76 - 0.90 µm) 30 m
- Band 5 Near-Infrared (1.55 - 1.75 µm) 30 m
- Band 6 Thermal (10.40 - 12.50 µm) 120 m
- Band 7 Mid-Infrared (IR) (2.08 - 2.35 µm) 30 m
- Ground Sampling Interval (pixel size): 30 m reflective, 120 m thermal
- Swath width: 185 km (115 miles)
More information about TM data can be found on https://lta.cr.usgs.gov/TM.
Landsat 4 Spacecraft Facts
- Manufactured by GE Astro Space, Fairchild
- Weight: approximately 1,941kg (4,279 lbs)
- 3-axis stabilized, zero momentum with control of 0.01º, using reaction wheels
- Single solar array with 1-axis articulation produces 1430 W
- Two NiCd batteries provide 100 Ah total power
- S-Band and Very High Frequency (VHF) communications
- Hydrazine propulsion system
Landsat 4 History (NASA Landsat Science)
The Multispectral Scanner (NASA Landsat Science)
The Thematic Mapper (NASA Landsat Science)