The Corona[1] program was a series of American strategic reconnaissance satellites produced and operated by the Central Intelligence Agency (CIA) Directorate of Science & Technology with substantial assistance from the U.S. Air Force. The CORONA satellites were used for photographic surveillance of the Soviet Union (USSR), China, and other areas beginning in June 1959 and ending in May 1972.HistoryIn 1957, the Soviet Union launched Sputnik 1, the first artificial Earth satellite. Officially, Sputnik was launched to correspond with the International Geophysical Year, a solar period that the International Council of Scientific Unions declared would be ideal for the launching of artificial satellites to study Earth and the solar system. However, the launch led to public concern about the perceived technological gap between the West and the Soviet Union.[2] The unanticipated success of the mission precipitated the Sputnik Crisis, and prompted President Dwight D. Eisenhower to authorize the Corona program, a top priority reconnaissance program managed jointly by the Air Force and the CIA. Satellites were developed to photograph denied areas from space, provide information about Soviet missile capability and replace risky U-2 reconnaissance flights over Soviet territory.[3]OverviewLockheed’s covert “advanced projects” facility at Hiller Aircraft in Menlo Park, CaliforniaCORONA image of The Pentagon, 25 September 1967CORONA started under the name “Discoverer” as part of the WS-117L satellite reconnaissance and protection program of the U.S. Air Force in 1956. The WS-117L was based on recommendations and designs from the RAND Corporation.[4] The primary goal of the program was to develop a film-return photographic satellite to replace the U-2 spyplane in surveilling the Sino-Soviet Bloc, determining the disposition and speed of production of Soviet missiles and long-range bombers assets. The CORONA program was also used to produce maps and charts for the Department of Defense and other U.S. government mapping programs.[5]The CORONA project was pushed forward rapidly following the shooting down of a U-2 spy plane over the Soviet Union on 1 May 1960.[6]CORONA ultimately encompassed eight separate but overlapping series of satellites (dubbed “Keyhole” or KH[7]), launched from 1959 to 1972.[8]: 231  CORONA was complemented and ultimately succeeded by the higher resolution KH-7 Gambit and KH-8 Gambit 3 series of satellites.[9]An alternative concurrent program to the CORONA program was SAMOS. That program included several types of satellite which used a different photographic method. This involved capturing an image on photographic film, developing the film aboard the satellite and then scanning the image electronically. The image was then transmitted via telemetry to ground stations. The Samos E-1 and Samos E-2 satellite programs used this system, but they were not able to take very many pictures and then relay them to the ground stations each day. Two later versions of the Samos program, such as the E-5 and the E-6, used the bucket-return approach pioneered with CORONA, but neither of the latter Samos series were successful.[10]SpacecraftThe CORONA satellites were designated KH-1, KH-2, KH-3, KH-4, KH-4A and KH-4B. KH stood for “Key Hole” or “Keyhole” (Code number 1010),[7] with the name being an analogy to the act of spying into a person’s room by peering through their door’s keyhole. The incrementing number indicated changes in the surveillance instrumentation, such as the change from single-panoramic to double-panoramic cameras. The “KH” naming system was first used in 1962 with KH-4, the earlier numbers being applied retroactively.