Want to stay on top of all the space news? Follow @universetoday on Twitter
Landsat 3 was the third satellite of NASA’s Landsat program. The satellite was launched on March 5, 1978, with the primary goal of providing a global archive of satellite imagery. Landsat 3 was managed solely by NASA unlike the majority of other Landsat missions. It was placed into a polar orbit at about 920 km above Earth. The satellite’s operational life was terminated (decommissioned) on March 21, 1983, having survived well beyond its designed one year life expectancy.
Landsats 2 and 3 had essentially the same design. Each had a Multi-Spectral Scanner(MSS) aboard. The MSS consisted of a fused silica mirror connected to three invar tangent bars which were mounted to the base of a Ni/ Au brazed invar frame in a serreuire truss that was arranged with four Hobbs links crossing at mid truss. This ensured that the secondary mirror would oscillate about the primary optic axis to maintain focus in spite of the expected vibration inherent from the 360 mm scan mirror. The Focal Plane Array consisted of 24 optical fibers in a 4×6 array. The fiber optic bundle transmitted signal through six photodiodes and 18 photomultiplier tubes. The scan monitor consisted of a diode source and sensor mounted at ends of four flat mirrors. The MSS had a maximum resolution 75 m. Landsat 3 had a thermal band capability, but this instrument failed shortly after satellite deployment.
The Landsat program is the longest running US satellite program for the acquisition of satellite imagery of Earth. The most recent satellite in the group, Landsat 7, was launched on April 15, 1999. The millions of images returned by the Landsat probes are a unique resource for research and have applications in agriculture, cartography, geology, forestry, regional planning, surveillance, education and national security.
We have written many articles about Landsat 3 for Universe Today. Here’s an article about Landsat 1, and here’s an article about Landsat 7.
We’ve also recorded an episode of Astronomy Cast all about planet Earth. Listen here, Episode 51: Earth.