KH-7 Gambit


codenamed GAMBIT, the KH-7 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 to. In 2002, all KH-7 satellite imagery, with the exception of some facilities in Israel, was declassified. Other details of the satellite program and construction remained classified until 2011.
In its summary report following the conclusion of the program, the National Reconnaissance Office concluded that the GAMBIT program was considered highly successful in that it produced the first high-resolution satellite photography, 69.4% of the images having a resolution under ; 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". In particular, its overall success stood in sharp contrast to the two first-generation photoreconnaissance programs, Corona, which suffered far too many malfunctions to achieve any consistent success, and SAMOS, which was essentially a complete failure with all satellites either being lost in launch mishaps or returning no usable imagery.
GAMBIT emerged in 1962 as an alternative to the less-than-successful CORONA and the completely failed SAMOS, although CORONA was not cancelled and in fact continued operating alongside the newer program into the early 1970s. While CORONA used the Thor-Agena launch vehicle family, GAMBIT would be launched on Atlas-Agena, the booster used for SAMOS. After the improved KH-8 GAMBIT-3 satellite was developed during 1965, operations shifted to the larger Titan IIIB launch vehicle.

System configuration

Each GAMBIT-1 satellite was about long, wide, weighed about, and carried about of film.
A feasibility study for the Geodetic Orbital Photographic Satellite System reveals three subsystems for U.S. optical reconnaissance satellites in the 1960s: the Orbital Control Vehicle, the Data Collection Module, and the Recovery Section. For the KH-7, the DCM is also called the Camera Optics Module, and is integrated in the OCV, which has a length of and a diameter of.

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 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° wide ground swath by exposing a wide moving portion of film through a small slit aperture. The initial ground resolution of the satellite was, but improved to by 1966. Each satellite weighed about, 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, and 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. Films were to be retrieved mid-air by a C-130 Hercules specially outfitted for that purpose.

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.
In early 1964, the CIA toyed with the idea of using GAMBIT to photograph military installations in Cuba, but this was dismissed as unworkable as the satellites were primarily designed with higher-latitude Soviet territory in mind and because it would mean wasting an entire satellite on the Latin America-Caribbean area which had little else of interest to U.S. intelligence services. It was decided that U-2 spyplane flights were adequate to provide coverage of Cuban activity.

ELINT subsatellite

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

List of launches

NameMission No.Launch DateAlt. NameNSSDC ID No.Launch VehiclePerigee Apogee Inclination
KH7-140011963-07-12OPS-1467Atlas-Agena D16416495.4
KH7-240021963-09-06OPS-1947Atlas Agena D16826394.4
KH7-340031963-10-25OPS-2196Atlas Agena D14433299.1
KH7-440041963-12-18OPS-2372Atlas Agena D12226697.9
KH7-540051964-02-25OPS-2423Atlas Agena D17319095.7
KH7-640061964-03-11OPS-3435Atlas Agena D16320395.8
KH7-740071964-04-23OPS-3743Atlas Agena D150366103.6
KH7-840081964-05-19OPS-3592Atlas Agena D141380101.1
KH7-940091964-07-06OPS-3684Atlas Agena D12134692.9
KH7-1040101964-08-14OPS-3802SLV-3 Agena D14930795.5
KH7-1140111964-09-23OPS-4262SLV-3 Agena D14530392.9
KH7-1240121964-10-08OPS-4036SLV-3 Agena D---------
KH7-1340131964-10-23OPS-4384Atlas Agena D13927188.6
KH7-1440141964-12-04OPS-4439SLV-3 Agena D15835797
KH7-1540151965-01-23OPS-4703SLV-3 Agena D146291102.5
KH7-1640161965-03-12OPS-4920SLV-3 Agena D93155
KH7-1740171965-04-28OPS-4983SLV-3 Agena D18025995.7
KH7-1840181965-05-27OPS-5236SLV-3 Agena D14926795.8
KH7-1940191965-06-25OPS-5501SLV-3 Agena D151283107.6
KH7-2040201965-07-12OPS-5810SLV-3 Agena D---------
KH7-2140211965-08-03OPS-5698SLV-3 Agena D149307107.5
KH7-2240221965-09-30OPS-7208SLV-3 Agena D9816495.6
KH7-2340231965-11-08OPS-6232SLV-3 Agena D14527793.9
KH7-2440241966-01-19OPS-7253SLV-3 Agena D15026993.9
KH7-2540251966-02-15OPS-1184SLV-3 Agena D14829396.5
KH7-2640261966-03-18OPS-0879SLV-3 Agena D162208101
KH7-2740271966-04-19OPS-0910SLV-3 Agena D139312116.9
KH7-2840281966-05-14OPS-1950SLV-3 Agena D133358110.5
KH7-2940291966-06-03OPS-1577SLV-3 Agena D14328886.9
KH7-3040301966-07-12OPS-1850SLV-3 Agena D13723695.5
KH7-3140311966-08-16OPS-1832SLV-3 Agena D14635893.3
KH7-3240321966-09-16OPS-1686SLV-3 Agena D14833393.9
KH7-3340331966-10-12OPS-2055SLV-3 Agena D15528791
KH7-3440341966-11-02OPS-2070SLV-3 Agena D15930591
KH7-3540351966-12-05OPS-1890SLV-3 Agena D137388104.6
KH7-3640361967-02-02OPS-4399SLV-3 Agena D136357102.4
KH7-3740371967-05-22OPS-4321SLV-3 Agena D13529391.5
KH7-3840381967-06-04OPS-4360SLV-3 Agena D149456104.8