Corona (satellite)The project was abandoned after a Soviet submarine was detected waiting below a Corona mid-air retrieval zone. After that, the launches were entirely secret.
The first launch with a camera was June 1959 as Discoverer 4, which was a 750 kg satellite launched by a Thor-Agena rocket. The two KH-4 systems improved the resolution to 2.75 m and 1.8 m respectively and used a lower altitude pass. Ironically, the name Corona was more fitting than its originators had ever imagined.
The last Corona launch was on 1972-05-25. Recommended corrective actions solving the problem included better grounding of spacecraft components and outgassing testing of parts before launch.
The best sequence of Corona launches was from 1966 to 1971, when there were 32 consecutive launch-and-film-recoveries. An alternative program named SAMOS included several satellite types that used a different method, taking an image on film, developing the film on board the spacecraft, and then scanning the image and transmitting it to the ground. The 1963 thriller novel Ice Station Zebra and its 1968 film adaptation were inspired, in part, by news accounts from April 17, 1959, about a missing experimental Corona satellite capsule (Discoverer II) that inadvertently landed near Spitsbergen on April 13 and was believed to have been recovered by Soviet agents. .
The KH naming system was first used in 1962 with KH-4 and the earlier numbers were retroactively applied. The Samos E-1 and E-2 satellite programs used this technology, but it was not able to take many pictures and relay them to the ground each day.
On February 22, 1995, the imagery acquired by the Corona and two contemporary programs (Argon and Lanyard) was declassified. There were 144 Corona satellites launched, of which 102 returned usable imagery. The Corona satellites used 31,500 ft (9,600 m) of special 70 mm film with a 24 inch (0.6 m) focal length lens.
The satellites returned film canisters to Earth in capsules, called buckets , which were recovered in mid-air by a specially equipped aircraft during their parachute descent (they were designed to float in water for a short period of time, and then sink, if the mid-air recovery failed). The return capsule of the Discoverer 13 mission, which launched August 10, 1960, was successfully recovered the next day. At least two Discoverer launches were used to test satellites for the Missile Defense Alarm System, an early missile-launch-detection program that used infrared cameras to detect the heat signature of rockets launching to orbit. The Corona film-return capsule was later adapted for the KH-7 GAMBIT satellite, which took higher resolution photos. The last launch under the Discoverer name was Discoverer 38 on 1962-02-26; with a successful midair recovery of the capsule on the 65th orbit (13th recovery, 9th in midair). KH stood for Key Hole or Keyhole (Code number 1010) , and the incrementing number indicated changes in the surveillance instrumentation, such as the change from single-panoramic to double-panoramic cameras.
The project name is sometimes given as CORONA, but it is a codeword, not an acronym. The project was accelerated after the U-2 incident in May 1960. The satellites were designated KH-1, KH-2, KH-3, KH-4, KH-4A and KH-4B. Eventually it was determined by a collaborative team of scientists and engineers from the project and from academia, (among them: Luis Alvarez, Sidney Beldner, Malvin Ruderman, and Sidney Drell) that electrostatic discharges (called corona discharge) caused by rubber components of the camera, were exposing the film.
These practices are still used on practically all US reconnaissance satellites today. The Air Force credits Onizuka Air Force Station as being the birthplace of the Corona program. The initial Corona launches were obscured as part of a space technology program called Discoverer, the first test launches for which were in early 1959. The initial missions of the program suffered from many technical problems, among them, mysterious fogging and bright streaks were seen on the returned film of some missions, only to disappear on the next mission.
Later Samos programs, such as the E-5 and the E-6, used the film-return approach, but neither one was successful. *(The stray quote marks are the original designations of the first three generations of cameras, as described in Perry s history.) Corona was officially secret until 1992. Initially orbiting at 165 to 460 km, the cameras could resolve images on the ground down to 7.5 m.
Corona was a US military reconnaissance satellite system operated by the CIA Directorate of Science & Technology with substantial assistance from the US Air Force, used for photographic surveillance of the Soviet Union, China and other areas from June 1959 until May 1972. Review of obsolete broad-area film-return systems other than Corona mandated by the order led to the 2002 declassification of the imagery from KH-7 and the KH-9 low-resolution camera system. The declassified imagery has since been used by a team of scientists from the Australian National University to locate and explore ancient habitation sites, pottery factories, megalithic tombs, and Palaeolithic remains in northern Syria.