KH-7 Gambit



Codenamed Gambit, the KH-7 (Air Force Program 206) was a reconnaissance satellite used by the United States from July 1963 to June 1967. Like the older CORONA system, it acquired imagery intelligence by taking photographs and returning the undeveloped film to earth. It achieved a typical ground-resolution of 2 ft to 3 ft. Though most of the imagery from the KH-7 satellites was declassified in 2002, details of the satellite program (and the satellite's construction) remained classified until 2011.

In its summary report following the conclusion of the program, the National Reconnaissance Office concluded that the GAMBIT project was considered highly successful in that it produced the first high resolution satellite photography, 69.4% of the images having a resolution under 3 ft. (0.91 m); its record of successful launches, orbits, and recoveries far surpassed the records of earlier systems; and it advanced the state of the art to the point where follow-on larger systems could be developed and flown successfully. The report also stated that GAMBIT had provided the intelligence community with the first high resolution satellite photography of denied areas, the intelligence value of which was considered "extremely high".

System Configuration
A feasibility study for the Geodetic Orbital Photographic Satellite System reveals three subsystems for US optical reconnaissance satellites in the 1960s: the Orbital (or Orbiting) Control Vehicle (OCV), the Data Collection Module (DCM), and the Recovery Section (RS). For the KH-7, the DCM is also called the Camera Optics Module (COM), and is integrated in the OCV, which has a length of 5.5 m and a diameter of 1.52 m.

Camera Optics Module
The Camera Optics Module of KH-7 consists of three cameras: a single strip camera, a stellar camera, and an index camera.

In the strip camera the ground image is reflected by a steerable flat mirror to a 1.21 m diameter stationary concave primary mirror. The primary mirror reflects the light through an opening in the flat mirror and through a Ross corrector. It took images of a 6.3 degree wide ground swath by exposing a 22 cm wide moving portion of film through a small slit aperture. The initial ground resolution of the satellite was 1.2 meters (4 ft), but improved to 0.6 m (2 ft) by 1966. Each satellite weighed about 2000 kg, and returned a single film bucket per mission. The camera and film transport system were manufactured by Eastman Kodak Company.

The index camera is a copy of cameras systems previously used in the KH-4 and KH-6 satellites, and takes exposures of Earth in direction of the vehicle roll position for attitude determination. The stellar camera takes images of star fields with a reseau grid being superimposed on the image plane. The S/I camera was provided by Itek, are horizon sensors were provided by Barnes Engineering Co.

Orbital Control Vehicle and Recovery Vehicle
The primary contractor for the Orbital Control Vehicle and the Recovery Vehicle was General Electric.

Mission
All KH-7 satellites were launched from Point Arguello, which became part of Vandenberg Air Force Base in July 1964. KH-7 satellites flew 38 missions, numbered 4001-4038, of which 34 returned film, and of these, 30 returned usable imagery. Mission duration was 1 to 8 days. KH-7 satellites logged a total of almost 170 operational days in orbit.

Functionality
A high-resolution instrument, the KH-7 took detailed pictures of "hot spots" and most of its photographs are of Chinese and Soviet nuclear and missile installations, with smaller amounts of coverage of cities and harbors. Most of the imagery from this camera, amounting to 19,000 images, 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. Approximately 100 frames covering the state of Israel remain classified.

The later KH-8 also used the Gambit codename.

ELINT subsatellite
Mission 4009 included an ELINT P-11 subsatellite for radar monitoring, which was launched into a higher orbit.

List of launches
(NSSDC ID Numbers: See COSPAR)

History

 * Section source: Space Review

In early 1963, the GAMBIT program began with failures. In May, an Atlas-Agena booster intended to launch the first GAMBIT satellite was sitting on the pad undergoing prelaunch tests when a problem developed with the Atlas's hydraulics system. Pad crews began draining the propellants, but in doing so accidentally released the nitrogen pressure gas from the booster. Its balloon skin began deflating and the whole Atlas crumpled to the ground, the RP-1 tank rupturing and spilling its contents onto the pad. However, there was no fire or explosion and the Agena stage was undamaged (the GAMBIT satellite was not on the booster).

A different Atlas booster was used and the first successful GAMBIT mission was launched on July 12, 1963. The Atlas rocket performed properly and when the fuel was exhausted it fell into the Pacific Ocean south of Vandenberg. The Agena’s Bell second-stage rocket engine then fired and put Gambit into polar orbit with a 102-mile (189 kilometers) altitude. The Air Force designated this mission number 4001.

Aerospace Corporation recommended that, during GAMBIT’s first flights, the Orbital Control Vehicle (OCV) should remain attached to the Agena. This was a proven successful process for other Agena tests; and whereas the OCV was not. This decision limited GAMBIT's functionality, meaning that photographs could only be taken of targets directly below the vehicle. Once the successful photographic phase of the mission 4002 was completed, the OVC and the Agena was separated and the reentry vehicle would come down into the ocean northwest of Hawaii. The re-entry vehicle was caught in mid-air with a C-130 Hercules aircraft. The film canister was then immedidately transported to Eastman Kodak's Hawkeye facility in Rochester, New York for processing. The developed results was sent to USAF imagery research analysts in Washington, DC.

GAMBIT mission 4003, was successfully launched on October 25, 1963. The film canister was again ejected successfully after the photographic phase and the capsule recovered by an aircraft. Other tests was carried out with the OCV.

GAMBIT mission 4004 was successfully launched and film canister recovered on December 18, 1963. Missions 4005 thru 4007 were also successful.

In May 1964 mission 4008 suffered major problems when the Agena did an unexplained roll during the boost phase. Even with OCV system problems, the film canister was able to return some imagery.

A variety of problems occurred with many of the remaining missions, with two ending with complete failure (in October 1964 and May 1965, both from Atlas control malfunctions that resulted in RSO destruction) and some with satellite placement but no imagery returned.

The KH-7 GAMBIT was an overall success, even with some failures; thus providing National Reconnaissance Office and the President with quality intelligence collection. Following KH projects had greatly improved major upgrades in the spacecraft and its camera systems.

Cost
The total cost of the 38 flight KH-7 program from FY1963 to FY1967, without non-recurring costs, and excluding five GAMBIT cameras sold to NASA, was US$ 651.4 million in 1963 dollars (inflation adjusted US$ billion present day). Non-recurring costs for industrial facilities, development, and one-time support amounted to 24.3% of the total program cost, or US$ 209.1 million. The resulting total program costs were US$ 860.5 million in 1963 dollars (inflation adjusted US$ billion present day).

Other U.S. imaging spy satellites

 * Corona series: KH-1, KH-2, KH-3, KH-4
 * KH-5 ARGON, KH-6 LANYARD
 * KH-7 and KH-8 GAMBIT
 * KH-9 HEXAGON "Big Bird"
 * KH-10 -- MOL
 * KH-11