In the mid-1960s, stimulated by U.S. successes in planetary exploration using unmanned remote sensing satellites and a September 21, 1966 announcement by the Department of the Interior Secretary Stewart Udall, the Department of the Interior, NASA, and the Department of Agriculture embarked on an ambitious effort to develop and launch the first civilian Earth observation satellite. Their goal was achieved on July 23, 1972, with the launch of the Earth Resources Technology Satellite (ERTS-1), which was later renamed Landsat 1. The launches of Landsat 2, Landsat 3, and Landsat 4 followed in 1975, 1978, and 1982, respectively.
When Landsat 5 launched in 1984, no one could have predicted that the satellite would continue to deliver high quality, global data of Earth’s land surfaces for 28 years and 10 months, officially setting a new Guinness World Record for "longest-operating Earth observation satellite." Landsat 6 failed to achieve orbit in 1993.