KH-9 HEXAGON, and commonly known as Big Bird, was a series of photographic reconnaissance satellites launched by the United States between 1971 and 1986. Of twenty launch attempts by the United States Air Force, all but one were successful. Camera film aboard Big Bird was sent back to earth in recoverable 'film return' capsules for processing and interpretation.
The KH-9 was originally conceived in the early 1960s as a replacement for the Corona search satellites. The goal was to search large areas of the earth with a medium resolution camera. The KH-9 carried two main cameras, although a mapping camera was also carried on several missions. The photographic film from the cameras was sent to recoverable re-entry vehicles and returned to earth, where the capsules were caught in mid-air by an aircraft. Four re-entry vehicles were carried on most missions, with a fifth added for missions that included a mapping camera.
Over the duration of the program the lifetime of the individual satellites increased steadily. The final KH-9 operated for up to 275 days. Different versions of the satellite varied in mass; most weighed 11,400 kilograms or 13,300 kg. Satellites were manufactured by Lockheed and the camera was designed by Itek, but produced by Perkin-Elmer. There were 20 launch attempts and one failure.
Missions 1205 through 1216 carried a "mapping camera" (also known as a "frame camera") that used 9 inch film and had a moderately low resolution of 9.1 meters (somewhat better than LANDSAT). Intended for mapmaking, photos this camera took cover essentially the entire Earth with at least some images between 1973 and 1980. Almost all the imagery from this camera, amounting to 29,000 images, each covering 3400 square km, was declassified in 2002 as a result of Executive order 12951, the same order which declassified CORONA, and copies of the films were transferred to the U.S. Geological Survey's Earth Resources Observation Systems office. Images from the mapping camera covering the state of Israel and all imagery from the KH-9's other cameras remain classified.
The KH-9 was never a backup project for the KH-10 Manned Orbital Laboratory. It was developed solely as a replacement for the Corona search system.
|Name||Mission no.||Launch date||NSSDC ID||Other Name||Launch vehicle|
|KH9-1||1201||1971 June 15||1971-056A||OPS 7809||Titan IIID|
|KH9-2||1202||1972 Jan 20||1972-002A||OPS 1737||Titan IIID|
|KH9-3||1203||1972 Jul 7||1972-052A||OPS 7293||Titan IIID|
|KH9-4||1204||1972 Oct 10||1972-079A||OPS 8314||Titan IIID|
|KH9-5||1205||1973 Mar 9||1973-014A||OPS 8410||Titan IIID|
|KH9-6||1206||1973 Jul 13||1973-043A||OPS 8261||Titan IIID|
|KH9-7||1207||1973 Nov 10||1973-088A||OPS 6630||Titan IIID|
|KH9-8||1208||1974 Apr 10||1974-020A||OPS 6245||Titan IIID|
|KH9-9||1209||1974 Oct 29||1974-085A||OPS 7122||Titan IIID|
|KH9-10||1210||1975 Jun 8||1975-051A||OPS 6381||Titan IIID|
|KH9-11||1211||1975 Dec 4||1975-114A||OPS 4428||Titan IIID|
|KH9-12||1212||1976 Jul 8||1976-065A||OPS 4699||Titan IIID|
|KH9-13||1213||1977 Jun 27||1977-056A||OPS 4800||Titan IIID|
|KH9-14||1214||1978 Mar 16||1979-029A||OPS 0460||Titan IIID|
|KH9-15||1215||1979 Mar 16||1979-025A||OPS 3854||Titan IIID|
|KH9-16||1216||1980 Jun 18||1980-052A||OPS 3123||Titan IIID|
|KH9-17||1217||1982 May 11||1982-041A||OPS 5642||Titan IIID|
|KH9-18||1218||1983 Jun 20||1983-060A||OPS 0721||Titan 34D|
|KH9-19||1219||1984 Jun 25||1985-065A||USA 2||Titan 34D|
|KH9-20||1220||1986 Apr 18||1986-F03||(launch failed)||Titan 34D|
(NSSDC ID Numbers: See COSPAR)
Data source: The Encyclopedia of US Spacecraft.