Landsat 4 was launched with the Multispectral Scanner (MSS) and a new advanced imaging sensor, Thematic Mapper (TM), allowing for clearer views of natural disasters from space.
Landsat 4 was launched from Vandenberg Air Force Base in California on July 16, 1982 on a Delta 3920 rocket. The sensors onboard the satellite collected data until late 1993, and the satellite was decommissioned on June 15, 2001. Landsat 4 was built and launched by NASA. NOAA initially oversaw the operations of the satellite but was eventually contracted out to the Earth Observation Satellite Company (EOSAT) in 1984. Despite numerous operations transfers, USGS EROS has remained responsible for the record and data keeping of the Landsat program.
Although the satellite was set in a lower orbit than Landsat 1-3, it had a higher field of view to retain the same swath width as its predecessors of 185 km (115 mi). The lower altitude results in a different swathing pattern.
With an updated design from the previous three missions, the satellite carried the MSS as well as the new TM instruments. It did not carry the Return Beam Vidicon (RBV) sensor.
Landsat 4 Satellite Orbit Facts
- Orbited the Earth in a sun-synchronous, near-polar orbit (98.2 degrees inclination)
- Reached an altitude of 705 km (438 mi)
- Circled the Earth every 99 minutes
- Had a 16-day repeat cycle with an equatorial crossing time of 9:45 a.m. +/- 15 minutes.
- 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 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)
Visit Landsat 1-5 MSS for more information.
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)
Visit Landsat 4-5 TM for more information.
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
Additional Resources
Landsat 4 History (NASA Landsat Science)
The Multispectral Scanner (NASA Landsat Science)
The Thematic Mapper (NASA Landsat Science)
