KH-8 Gambit 3


The KH-8 was a long-lived series of reconnaissance satellites of the "Key Hole" series used by the United States from July 1966 to April 1984, and also known as Low Altitude Surveillance Platform. 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. 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 in length. They carried 12,241 feet of film and were designed for longer missions of up to 31 days

Camera Optics Module

The Camera Optics Module of KH-8 consists of four cameras.
The main camera of KH-8B with a focal length of is a single strip camera, designed to gather high-resolution images of ground targets. In the strip camera the ground image is reflected by a steerable flat mirror to a diameter stationary concave primary mirror. The primary mirror reflects the light through an opening in the flat mirror and through a Ross corrector. At periapsis altitude of 75 nautical miles, the main camera imaged a 6.3 km wide ground swath on a wide moving portion of film through a small slit aperture, resulting in an image scale of 28 meter / millimeter. The Astro-Position Terrain Camera contains three cameras: a 75mm focal length terrain frame camera, and two 90mm focal length stellar cameras. The terrain frame camera takes exposures of Earth in direction of the vehicle roll position for attitude determination. The stellar cameras observed in 180 degree opposite directions and took images of star fields.
The films used by GAMBIT were provided by Eastman Kodak, and evolved through a series of successively higher definition films, starting with Type 3404 with a resolving power of 50 to 100 line pairs per mm. Subsequent films used were Type 1414 high-definition film, SO-217 high-definition fine-grain film, and a series of films with silver-halide crystals of very uniform size and shape. The size of silver-halide crystals decreased from 1,550 angstrom in film Type SO-315, to 1,200 angstrom in SO-312, and ultimately to 900 angstrom in SO-409. Under optimal conditions GAMBIT would thus have been able to record ground features as small as 0.28 m to 0.56 m using the Eastman Kodak Type 3404 film. Using a film with a resolving power equivalent to the Kodak's Type 3409 film of 320 to 630 line pairs per mm, GAMBIT would have been able to record ground features as small as 5 cm to 10 cm . The initial September 2011 release of "The Gambit Story" quotes "The mature system produced examples of imagery better than four inches ground-resolution distance". This number was again redacted in a later release. Five to ten centimeters corresponds to the resolution limit imposed by atmospheric turbulence as derived by Fried and, independently, Evvard in the mid-1960s; remarkably, GAMBIT had reached a physical limit on resolution only a few years after the US launched its first reconnaissance satellite. GAMBIT was also able to record objects in orbit. The capability was developed to photograph Soviet spacecraft, but was first used to aid NASA engineers designing repairs for the damaged Skylab space station in 1973.

Missions

NameBlockLaunch DateAlt. NameNSSDC ID No.Launch VehicleOrbitDecay date
KH8-1I1966-07-29OPS-3014Titan IIIB158.0 km × 250.0 km, i=94.1°1966-08-06
KH8-2I1966-09-28OPS-4096Titan IIIB
KH8-3I1966-12-14OPS-8968Titan IIIB
KH8-4I1967-02-24OPS-4204Titan IIIB
KH8-5I1967-04-26OPS-4243, 1967-003XTitan IIIBno stable orbit1967-04-26
KH8-6I1967-06-20OPS-4282Titan IIIB
KH8-7I1967-08-16OPS-4886Titan IIIB
KH8-8I1967-09-19OPS-4941Titan IIIB
KH8-9I1967-10-25OPS-4995Titan IIIB
KH8-10I1967-12-05OPS-5000Titan IIIB
KH8-11I1968-01-18OPS-5028Titan IIIB
KH8-12I1968-03-13OPS-5057Titan IIIB
KH8-13I1968-04-17OPS-5105Titan IIIB
KH8-14I1968-06-05OPS-5138Titan IIIB
KH8-15I1968-08-06OPS-5187Titan IIIB
KH8-16I1968-09-10OPS-5247Titan IIIB
KH8-17I1968-11-06OPS-5296Titan IIIB
KH8-18I1968-12-04OPS-6518Titan IIIB
KH8-19I1969-01-22OPS-7585Titan IIIB
KH8-20I1969-03-04OPS-4248Titan IIIB
KH8-21I1969-04-15OPS-5310Titan IIIB
KH8-22I1969-06-03OPS-1077Titan IIIB
KH8-23II1969-08-23OPS-7807Titan 23B
KH8-24II1969-10-24OPS-8455Titan 23B
KH8-25II1970-01-14OPS-6531Titan 23B
KH8-26II1970-04-15OPS-2863Titan 23B
KH8-27II1970-06-25OPS-6820Titan 23B
KH8-28II1970-08-18OPS-7874Titan 23B
KH8-29II1970-10-23OPS-7568Titan 23B
KH8-30II1971-01-21OPS-7776Titan 23B139.0 km × 418.0 km, i=110.8°1971-02-09
KH8-31II1971-04-22OPS-7899Titan 23B132.0 km × 401.0 km, i=110.9°1971-05-13
KH8-32II1971-08-12OPS-8607Titan 24B137.0 km × 424.0 km, i=111.0°1971-09-03
KH8-33II1971-10-23OPS-7616Titan 24B134.0 km × 416.0 km, i=110.9°1971-11-17
KH8-34II1972-03-17OPS-1678Titan 24B131.0 km × 409.0 km, i=111.0°1972-04-11
KH8-35II1972-05-20OPS-65741972-F03Titan 24Bfailed to reach orbit
KH8-36II1972-09-01OPS-8888Titan 24B140.0 km × 380.0 km, i=110.5°1972-09-30
KH8-37III1972-12-21OPS-3978Titan 24B139.0 km × 378.0 km, i=110.5°1973-01-23
KH8-38III1973-05-16OPS-2093Titan 24B139.0 km × 399.0 km, i=110.5°1973-06-13
KH8-39III1973-06-26OPS-40181973-F04Titan 24Bfailed to reach orbit
KH8-40III1973-09-27OPS-6275Titan 24B131.0 km × 385.0 km, i=110.5°1973-10-29
KH8-41III1974-02-13OPS-6889Titan 24B134.0 km × 393.0 km, i=110.4°1974-03-17
KH8-42III1974-06-06OPS-1776Titan 24B136.0 km × 394.0 km, i=110.5°1974-07-24
KH8-43III1974-08-14OPS-3004Titan 24B135.0 km × 402.0 km, i=110.5°1974-09-29
KH8-44III1975-04-18OPS-4883Titan 24B134.0 km × 401.0 km, i=110.5°1975-06-05
KH8-45III1975-10-09OPS-5499Titan 24B125.0 km × 356.0 km, i=96.4°1975-11-30
KH8-46III1976-03-22OPS-7600Titan 24B125.0 km × 347.0 km, i=96.4°1976-05-18
KH8-47III1976-09-15OPS-8533Titan 24B135.0 km × 330.0 km, i=96.4°1976-11-05
KH8-48IV1977-03-13OPS-4915Titan 24B124.0 km × 348.0 km, i=96.4°1977-05-26
KH8-49IV1977-09-23OPS-7471Titan 24B125.0 km × 352.0 km, i=96.5°1977-12-08
KH8-50IV1979-05-28OPS-7164Titan 24B124.0 km × 305.0 km, i=96.4°1979-08-26
KH8-51IV1981-02-28OPS-1166Titan 24B138.0 km × 336.0 km, i=96.4°1981-06-20
KH8-52IV1982-01-21OPS-2849Titan 24B630.0 km × 641.0 km, i=97.4°1982-05-23
KH8-53IV1983-04-15OPS-2925Titan 24B124.0 km × 254.0 km, i=96.5°1983-08-21
KH8-54IV1984-04-17OPS-8424Titan 24B127.0 km × 235.0 km, i=96.4°1984-08-13

Cost

The total cost of the 54 flight KH-8 program from FY1964 to FY1985, without non-recurring costs, was US$2.3 billion in respective year dollars.

Other U.S. imaging spy satellites