Landsat 1 (LS-1), formerly named ERTS-A and ERTS-1, was the first satellite of the United States' Landsat program. It was a modified version of the Nimbus 4 meteorological satellite and was launched on July 23, 1972, by a Delta 900 rocket from Vandenberg Air Force Base in California.

It was the first satellite to carry a Multispectral Scanner.

The near-polar orbiting spacecraft served as a stabilized, Earth-oriented platform for obtaining information on agricultural and forestry resources, geology and mineral resources, hydrology and water resources, geography, cartography, environmental pollution, oceanography and marine resources, and meteorological phenomena.