Thirty years ago today — July 16, 1982 — Landsat 4 launched atop a Delta rocket out of Vandenberg AFB.
(Landsat 4. NASA image.)
Though it was the fourth in the Landsat series of spacecraft, Landsat 4 “was a major step forward in global remote-sensing applications.” According to this NASA page,
In addition to the Multispectral Scanner System (MSS) instrument, Landsat 4 (and Landsat 5) carried a sensor with improved spectral and spatial resolution, i.e., the new satellites could see a wider (and more scientifically-tailored) portion of the electromagnetic spectrum and could see the ground in greater detail. This new instrument was known as the Thematic Mapper (TM).
The Landsat 4 TM instrument had seven spectral bands. Data was collected from the blue, green, red, near-infrared, mid-infrared (2 bands) and thermal infrared portions of the electromagnetic spectrum.
The Thematic Mapper was an important addition to the environmental monitoring instrumentation, and later Landsat spacecraft carried improved versions of it.
Landsat 4 was designed to operate for 3 years. Although some of its components failed, it continued to operate in a limited capacity until 1993. Thereafter, the spacecraft sent telemetry data until 2001, when it was decommissioned.
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