KH-8 Gambit 3

KH-8 GAMBIT
Schematics of GAMBIT-3 and Agena D
Mission typeImagery intelligence
OperatorNational Reconnaissance Office
Spacecraft properties
Manufacturer
Launch mass4100 kg (on orbit)
Dimensions14.75 m × 1.52 m (48.4 ft × 5.0 ft)
Start of mission
RocketTitan III
Launch siteVandenberg Air Force Base, SLC-4E
ContractorMartin Marietta
Orbital parameters
Reference systemSun-synchronous orbit
RegimeLow Earth orbit
Perigee altitude135 km (84 mi)
Apogee altitude305 km (190 mi)
Inclination110.5°
Main telescope
TypeAspheric reflector with five-element Ross corrector
Diameter1.1 m (3 ft 7 in)
Focal length4.46 m (14.6 ft)
Focal ratiof/4.09
Wavelengthsvisible light, Near-infrared

The KH-8 (BYEMAN codename Gambit-3)[1] was a long-lived series of reconnaissance satellites of the "Key Hole" (KH) series used by the United States from July 1966 to April 1984,[2] and also known as Low Altitude Surveillance Platform.[3] The satellite ejected "film-bucket" canisters of photographic film that were retrieved as they descended through the atmosphere by parachute. Ground resolution of the mature satellite system was better than 4 inches (0.10 m).[4] There were 54 launch attempts of the 3,000 kilogram satellites, all from Vandenberg Air Force Base, on variants of the Titan III rocket. Three launches failed to achieve orbit. The first one was satellite #5 on April 26, 1967, which fell into the Pacific Ocean after the Titan second stage developed low thrust. The second was satellite #35 on May 20, 1972, which suffered an Agena pneumatic regulator failure and reentered the atmosphere. A few months later, pieces of the satellite turned up in England and the US managed to arrange for their hasty return. The third failure was satellite #39 on June 26, 1973, which suffered a stuck Agena fuel valve. The Bell 8096 engine failed to start and the satellite burned up in the atmosphere. The KH-8 was manufactured by Lockheed. The camera system/satellite was manufactured by Eastman Kodak's A&O Division in Rochester, New York.

The Gambit codename was also used by the satellite's predecessor, the KH-7 Gambit.

Gambit 3 satellites were the same width as the Gambit 1 models, but also slightly longer – reaching about 29 feet (8.8 m) in length. They carried 12,241 feet (3,731 meters) of film and were designed for longer missions of up to 31 days.[5]

While Gambit was primarily designed and operated as a surveillance satellite, capturing high definition images of specific targets at low orbital altitudes, a single Gambit Block 3 mission was operated in 'dual-mode', orbiting first at a higher altitude to capture wide-area search imagery before lowering its perigee to capture normal surveillance imagery. The first film return capsule failed to separate correctly due to a new pyro mechanism failing to perform correctly. The contingency release mechanism separated the film bucket and parachute from its return capsule, and left the film bucket stranded in orbit. In September 2002, the film bucket re-entered over the South Atlantic into deep water. As the film bucket lacked its protective heatshield or the parachute needed to slow its descent, no attempt was made to recover it.[6]

  1. ^ "GAMBIT 3 KH-8 Reconnaissance Satellite". National Museum of the U.S. Air Force. Retrieved August 10, 2022.
  2. ^ Richelson, Jeffrey (1987). American espionage and the Soviet target. W. Morrow. p. 195. ISBN 978-0-688-06753-3.
  3. ^ Global Security Space Systems IMINT Overview LASP
  4. ^ Cite error: The named reference NRO_GAMBITStory was invoked but never defined (see the help page).
  5. ^ "Declassified US Spy Satellites from Cold War Land in Ohio". Space.com. January 28, 2012. Retrieved October 11, 2015.
  6. ^ "GAMBIT_Dual_Mode". www.nro.gov. Retrieved February 19, 2021.