|Launch date||March 5, 1978|
|Carrier rocket||Delta 2910|
|Launch site||Vandenberg AFB SLC-2W|
|Altitude||917 km (570 mi)|
|Repeat interval||18 days|
|Swath width||185 km (115 mi)|
|Equatorial crossing time||9:30 AM +/- 15 minutes|
Landsat 3 is the third satellite of the Landsat program. It was launched on March 5, 1978, with the primary goal of providing a global archive of satellite imagery (satellite data are called images and not photos because they are not just reflected light exposure, but recordings of radiative electromagnetic energy fluxes of surface materials). Unlike later Landsats, Landsat 3 was managed solely by NASA. Landsat 3 is no longer in operation, having been decommissioned on March 21, 1983, far beyond its designed life expectancy of one year.
Landsat 3 had essentially the same design as Landsat 2. It carried a Multi-Spectral Scanner, which had a maximum 75m resolution. Unlike the previous two Landsat missions a thermal band was built into Landsat 3, but this instrument failed shortly after the satellite was deployed. Landsat 3 was placed into a polar orbit at about 920 kilometers, and took 18 days to cover the entire Earth's surface.