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Landsat 4 History
July 16, 1982 – (placed in standby in January 1986) December 14, 1993
Decommissioned: June 15, 2001
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Figure 1. Landsat 4
Participants
- NASA
- National Oceanic and Atmospheric Administration (NOAA)
- Earth Observation Satellite Company (EOSAT)
- Department of the Interior (DOI) U.S. Geological Survey (USGS)
Launch
- Date: July 16, 1982
- Vehicle: Delta 3920
- Launched by: NASA
- Site: Vandenberg Air Force Base, California
Spacecraft
- 3-axis stabilized, zero momentum with control of 0.01 deg using reaction wheels
- Aluminum with graphite struts
- Hydrazine propulsion system
- Single solar array with 1-axis articulation
- Three Nickel Cadmium (NiCd) batteries provide 100 Ampere-Hour (AHr ) total
- Retractable boom (4 m long) with 2 powered joints supports the articulated High Gain Antenna, which downlinked data via the Tracking and Data Relay Satellite System (TDRSS)
- Weight: approximately 4,300 lbs (1,942 kg)
Communications
- Direct downlink with TDRSS
- Data rate: 85 Mbps
- Communications system uses S, X, L, and Ku Bands
- Quantization: 8 bit (256 levels)
Orbit
- Worldwide References System-2 (WRS-2) path/row system
- Circular, sun-synchronous, near-polar orbit at an altitude of 705 km (438 mi)
- Inclined at 98.2°
- Circled the Earth every 99 minutes
- Repeat cycle: 16 days
- Equatorial crossing time: 9:45 a.m. +/- 15 minutes
- Swath width: 185 km (115 mi)
Sensors
Multispectral Scanner (MSS)
- Four spectral bands (identical to Landsat 1 and 2):
- 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
Thematic Mapper (TM)
- 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
Other Characteristics
- Scene size: 170 km x 185 km (106 mi x 115 mi)
- Also known as Landsat-D
- Design Life: Minimum of 3 years
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U.S. Department of the Interior |
U.S. Geological Survey
