Keyhole

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Satellite images and the stereoscopic image system of a satellite

Keyhole ( English for keyhole ) or KH for short refers to a series of types of American optical spy satellites . A total of at least 287 KH series satellites were launched. Originally, however , Keyhole only referred to the security system with which satellite images were to be kept secret.

KH-1, -2, -3, -4, -4A, -4B Corona

KH-4B Corona satellite
Recovery of the return capsule from Discoverer 14 (typical for the KH-1 to KH-9 series)
KH-7 image from the Indian Bhabha Atomic Research Center (BARC) in Trombay 1966

The first satellites (types KH-1 to KH-4B) were also called Corona . KH-1 started in 1960. The cameras of these satellites had resolutions of initially 7.5 m, later up to 1.5 m. After launch, their orbit had an apogee of approx. 460 km and a perigee of approx. 165 km. The images were recorded on conventional film . In 1962, KH-4 was the first satellite to also record stereoscopic images . The main target areas for the satellites were the USSR and the People's Republic of China . From 1967 at the latest, the Middle East was repeatedly observed. B. Recordings before and after the Six Day War were compared. Because the transmission of images by radio was not yet so well developed and not yet sufficiently secure against eavesdropping, the films were brought back to earth with re-entry capsules that were suspended from a parachute and intercepted by an airplane .

The type KH-4B had two panorama cameras with aperture 1: 3.5 and 24 inches (61 cm) focal length and an index camera (for the overview). During the 19 days of the mission, up to 9,600 m of 70 mm film (almost always black and white) were exposed and wound into the cassettes of the two return capsules. After separating a capsule, first its rotation and then the airspeed were slowed down with a rocket motor. When re-entering the atmosphere, the shock wave slowed down first, then - with the heat shield removed - a small braking parachute, finally a main parachute, which only opened fully at an altitude of 15,000 m before the glider and capsule were fished up in the air by an aircraft.

The first launches of Corona satellites took place in early 1959 under the code name Discoverer, the first satellite equipped with a camera was launched in June of the same year as Discoverer 4 (mass approx. 750 kg), but did not provide any usable images. Discoverer 14 provided the first usable images on August 19, 1960. The name Discoverer was used until Discoverer 38 in 1962. From 1959 to 1972, a total of 145 Corona satellites were launched with different variants of the Thor-Agena rocket, 102 of which provided useful images.

KH-5 argon

KH-5 , also known as Argon , was built by Lockheed between February 1961 and August 1964. Similar to the Corona satellites, the film was brought to earth by re-entry capsule. The mass of the satellite was 1,150 to 1,500 kg, depending on the version. A total of twelve satellites were launched with Thor-Agena missiles, with at least 7 failures. The resolution of the satellite camera was only 140 m, it was used to make larger maps.

KH-6 lanyard

KH-6 , also known as the Lanyard , was also produced by Lockheed and was in service between March and July 1963. The resolution was 1.8 m, the film was brought back in a re-entry capsule. There were three launches, one of which failed and another was a test satellite with no film. Here, too, launchers of the Thor Agena type were used. The aim of the KH-6 program was to obtain high-resolution images.

KH-7 Gambit

Spy satellite KH-7 Gambit

KH-7 ( Gambit ) was built by General Electric from July 1963 to June 1967 . Unlike the previous satellites, information about this type is still top secret. The resolution is probably 0.5 m, there have been at least 38 satellite launches with Atlas Agena rockets.

KH-8 Gambit

KH-8 (also called Gambit ) was in service from July 1966 to April 1984 and was built by Lockheed (?). The best resolution achieved was less than 0.1 m. The satellite stayed in orbit longer than its predecessor; the images were also brought back here with re-entry capsules, there were at least 55 satellite launches. The launch vehicle was the Titan 3B Agena .

KH-9 hexagon

A KH-9 satellite in orbit
Re-entry capsule from a KH-9 satellite in the National Museum of the United States Air Force

KH-9 ( Hexagon , " Big Bird ", built by Lockheed) was in service from June 1971 to April 1986. The mass of the satellite was approx. 11 to 13 tons, the resolution of the camera approx. 0.6 m. The film was returned to Earth with 4 re-entry pods. There were 20 launches with Titan 3D and Titan 34D missiles. KH-9 was developed parallel to KH-10 / MOL as an unmanned alternative.

KH-10 Dorian / MOL

Artist's impression of the MOL (KH-10) in orbit

KH-10 ( Dorian ) was a planned manned space station called the Manned Orbiting Laboratory (MOL) - actually a manned spy satellite combined with a Gemini spacecraft. The project was abandoned after a flight test in 1969 before a functional space station could be put into orbit. The planned launch vehicle would have been the Titan-3M . After the program was discontinued, the KH-9 hexagon satellite, which was developed in parallel, was taken into service.

KH-11 Kennan, later Crystal

KH-11 ( Crystal , Kennan ) was built by Lockheed from December 1976 to November 1988 and was the first usable American spy satellite to transmit the images by radio. The satellites were similar to the Hubble space telescope with a 2.3 m mirror, the resolution was about 15 cm. At least nine satellites were launched with Titan 3D and Titan 34D rockets; the typical lifespan of a satellite was around 3 years.

KH-12 (?)

KH-12 ( Ikon (?), Improved Crystal ) is essentially an improved variant of the KH-11 model and has a mirror with a diameter of 4.04 m. A large number of SIGINT systems and a laser rangefinder are on board as additional payloads . The optical sensors work in the visible and in the low infrared spectrum in order to be able to localize and identify heat sources and camouflaged or underground targets. The CCD sensor uses photocells based on gallium arsenide in order to achieve a better resistance to laser interference measures compared to the older silicon cells , whereby a specially laser-resistant coated lens is used for this. When fully fueled, the satellite weighs up to 18 tons and carries around 5.3 tons of fuel. It is primarily designed by Lockheed Martin .

At least 5 satellites have been launched since 1992, and a sixth is said to have been launched in 2007 or 2008. Neither the designation KH-12 nor the code name Ikon have been officially confirmed. Launch rockets were the space shuttle and Titan-4A rockets.

KH-13 (?)

KH-13 ( Misty ) may be the successor to KH-12. One can only speculate about its existence, allegedly three satellites of this series were launched in 1990 with a space shuttle and in 1999 and 2005 with Titan-4B rockets. The designation KH-13 is not officially confirmed. The names 8X and EIS (Enhanced Imaging System) were also mentioned in connection with this satellite.

Awards

In 2005, James W. Plummer , Minoru S. Araki , Francis J. Madden , Edward A. Miller and Don H. Schoessler received the Charles Stark Draper Prize for their participation in Corona.

literature

  • Dwayne A. Day, John M. Logsdon, Brian Latell (Eds.): Eye in the Sky: The Story of CORONA Spy Satellites . Smithsonian Institution Press, 1998
  • Curtis Peebles: The Corona Project: America's First Spy Satellites . Naval Inst. Press, 1997
  • Kevin C. Ruffner (Ed.): Corona: America's First Satellite Program . Morgan James, New York 1995.
  • Robert McDonald (Ed.): Corona: Between the Sun & the Earth: The First NRO Reconnaissance Eye in Space . ASPRS, Bethesda MD 1997.

Web links

Individual evidence

  1. ↑ a b Kevin C. Ruffner: Corona: America's First Satellite Program. (PDF; 19.3 MB) Center for the Study of Intelligence, Central Intelligence Agency , 1995, accessed December 6, 2009 .
  2. ↑ The Retirement of BYEMAN. (PDF; 386 kB) NRO Security Newsletter, 2004, accessed on December 6, 2009 .
  3. ↑ Recovery Sequence in US Centennial of Flight Commission ( Memento from September 30, 2012 in the Internet Archive )
  4. ↑ KH-4A camera system, drawing
  5. ↑ Corona Facts. National Reconnaissance Office , archived from the original on January 10, 2012 ; accessed on February 8, 2013 .
  6. ↑ The Gambit Story, BYE 140002-90, Appendix A, Science and Technical Intelligence, p. 154. National Reconnaissance Office , June 1991, archived from the original on March 2, 2013 ; accessed in September 2011 .
  7. ↑ a b c d Jane’s Space Directory 2002
  8. ↑ a b c d e Improved - Advanced Crystal / IKON / "KH-12" Recoinassance imaging spacecraft , GlobalSecurity.org
  9. ↑ Rainer Paul: Armor: Tandem of the sky scouts . In: Der Spiegel . No. 42 , 1997 ( online ).
  10. ↑ Stefan Schmitt: Spy satellites: amateurs hunt dark scouts. Spiegel Online , February 20, 2006, accessed December 9, 2009 .