description Landsat 4 Overview
Landsat 4 was a joint NASA and U.S. Geological Survey Earth observation satellite launched on July 16, 1982 into a Sun-synchronous near-polar orbit at approximately 705 km altitude. It carried the Thematic Mapper sensor, which provided 30-meter resolution in six visible and infrared bands plus a 120-meter thermal infrared band, significantly improving on earlier Landsat instruments. Landsat 4 was removed from operational service in 1993 after Ku-band transmitter failures but remained in orbit until its decommissioning.
insights Ranking position
Landsat 4 ranks #47 of 187 in the Satellite ranking, behind Radarsat-2, ahead of Sentinel-3B.
help Landsat 4 FAQ
What made Landsat 4's Thematic Mapper different from earlier Landsat instruments?
The Thematic Mapper (TM) on Landsat 4 was a major upgrade over the older Multispectral Scanner, offering 30-meter multispectral resolution and adding new spectral bands in the mid-infrared and thermal infrared regions. These additions significantly improved the ability to distinguish vegetation types, soil moisture, and mineral compositions from orbit.
Can I still download Landsat 4 imagery today?
Yes, Landsat 4 Thematic Mapper data is freely available through the USGS EarthExplorer portal as part of the Landsat archive that has been open access since the 2008 USGS data policy change. Researchers can also access processed Landsat 4 collections via Google Earth Engine for time-series analysis.
When did Landsat 4 stop operating?
Landsat 4 was launched on July 16, 1982, but suffered satellite bus failures in the mid-1980s that limited its operational capacity. It was kept in standby mode and officially decommissioned in 1993, with Landsat 5 ensuring continuity of the program.
Why did Landsat 4 lose its solar panels?
In 1983, Landsat 4 experienced failures in its power system when its solar panels degraded, significantly reducing the satellite's operational capability. This power anomaly was one of the key reasons NASA accelerated the launch of Landsat 5 in 1984 to maintain data continuity.
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