Landsat program
Landsat 1, then known as ERTA-A, was launched July 23, 1972. The satellite took over 100,000 images of the Earth over the course of its life. Landsat 2 had a similar design, and was launched three years later. Landsat 3, launched in 1978, was the last satellite to have a similar design to Landsat 1, and was the last Landsat to be managed by NASA during the Landsat program. Landsat 4 was the first Landsat to be operated by NOAA.