The First Earth Resources Technology Satellite (LANDSAT) is Launched

On July 23, 1972 NASA launched the Earth Resources Technology Satellite, later renamed Landsat, for the acquisition of satellite imagery of Earth.

"The most recent [satellite in the series], Landsat 8, was launched on February 11, 2013. The instruments on the Landsat satellites have acquired millions of images. The images, archived in the United States and at Landsat receiving stations around the world, are a unique resource for global change research and applications in agriculture, cartography, geology, forestry, regional planning, surveillance and education" (Wikipedia article on Landsat Program, accessed 10-20-2013).