This photo, of the Soviet Union’s Dolon Air Field in August 1966, shows more detail, including the location of heavy bombers–a very important detail at the height of the Cold War.
When President Eisenhower approved the program in 1958, and throughout its 12-year run, information on military and aerospace efforts in the Soviet Bloc was very hard to come by, and the satellite’s eye in the sky helped the U.S. to peak behind the (iron) curtain. Corona, actually the name of a series of satellites used in the program, was a joint effort of the Defense Department and the Central Intelligence Agency.
According to the NRO Web site, the resolution of Corona’s images was 6 feet at its sharpest, 560 feet at its worst. Individual satellite images covered a land are of approximately 10 miles by 120 miles.