KH-11 KENNEN
The KH-11 KENNEN is a type of reconnaissance satellite first launched by the American National Reconnaissance Office in December 1976. Manufactured by Lockheed in Sunnyvale, California, the KH-11 was the first American spy satellite to use electro-optical digital imaging, and to offer real-time optical observations.
Later KH-11 satellites have been referred to by outside observers as KH-11B or KH-12, and by the names "Advanced KENNEN", "Improved Crystal" and "Ikon". Official budget documents refer to the latest generation of electro-optical satellites as Evolved Enhanced CRYSTAL System. The Key Hole series was officially discontinued in favor of a random numbering scheme after repeated public references to KH-7 GAMBIT, KH-8 GAMBIT 3, KH-9 HEXAGON, and KH-11 KENNEN satellites.
The capabilities of the KH-11 are highly classified, as are the images they produce. The satellites are believed to have been the source of some imagery of the Soviet Union and China made public in 1997; images of Sudan and Afghanistan made public in 1998 related to the response to the 1998 U.S. embassy bombings; and a 2019 photo, provided by then-President Donald Trump, of a failed Iranian rocket launch.
Program history
Before KENNEN, National Reconnaissance Office spy satellites such as KH-9 HEXAGON took photographs on film, which was dropped to Earth in capsules. The satellites' useful life ended when they ran out of film or capsules.The Film Read-Out KH-7 GAMBIT served as NRO Program A's competitor to NRO Program B's initial electro-optical imagery satellite. After a precursor EOI study under the codeword Zoster, President Nixon on 23 September 1971 approved the development of an EOI satellite codenamed Zaman. In November 1971, this codeword was changed to Kennen, which is Middle English for "to perceive". Initial director of the ZAMAN/KENNEN Program Group was Charles R. "Charlie" Roth; he was succeeded in October 1975 by Rutledge P. Hazzard.
The KENNEN system transmits its imagery as data through the Satellite Data System, a network of communications satellites. These digital images were initially processed at a secret National Reconnaissance Office facility dubbed Area 58 at Fort Belvoir in Virginia.
In 1999, NRO selected Boeing as the prime contractor for the Future Imagery Architecture program, which aimed to replace the KH-11 satellites by a more cost-effective constellation of smaller, more capable reconnaissance satellites. After the failure of the FIA in 2005, NRO ordered two more KH-11s from Lockheed. USA-224, the first of these, was launched in early 2011 two years ahead of the initial schedule estimate.
Design
Initial design specifications
According to Lew Allen, the initial key design elements were specified by Edwin H. Land. They included i) solid state focal plane array, ii) integrated circuits for complex data processing, iii) large, fast optics with a diameter f/2 primary mirror, iv) gigabit/s data link, v) long on-orbit operational lifetime for the imaging satellites, and vi) communication satellites to facilitate close-to-realtime downlink of the images.Size and mass
KH-11s are believed to resemble the Hubble Space Telescope in size and shape, as they were shipped in similar containers. Their length is believed to be 19.5 meters, with a diameter of up to. A NASA history of the Hubble, in discussing the reasons for switching from a 3-meter main mirror to a design, states: "In addition, changing to a 2.4-meter mirror would lessen fabrication costs by using manufacturing technologies developed for military spy satellites".Different versions of the KH-11 vary in mass. Early KH-11s were reported to be comparable in mass to HEXAGON, i.e. about. Later blocks are believed to have a mass of around to.
Propulsion module
It has been reported that KH-11s are equipped with a hydrazine-powered propulsion system for orbital adjustments. In order to increase the orbital lifetime of KH-11s, plans existed for refuelling the propulsion module during service visits by the Space Shuttle. It has been speculated that the propulsion module is related to Lockheed's Satellite Support Bus, which had been derived from the Satellite Control Section developed by Lockheed for KH-9.Optical Telescope Assembly
A CIA history states that the primary mirror on the first KH-11s measured, but sizes increased in later versions. NRO led the development of a computer controlled mirror polishing technique, which was subsequently also used for the polishing of the primary mirror of the Hubble Space Telescope.Later satellites had larger mirrors, with a diameter of around. Jane's Defence Weekly indicates that the secondary mirror in the Cassegrain reflecting telescope system could be moved, allowing images to be taken from angles unusual for a satellite. Also, there are indications that the satellite can take images every five seconds.
Imaging sensors and camera modes
The initial KH-11 camera system offered frame and strip modes. The focal plane was equipped with an array of light-sensitive silicon diodes, which converted brightness values to electrical signals. The packaging density was sufficiently high to match the ground sample distance of the CORONA satellites. The recorded digital signal was encrypted and transmitted to a ground station in near real time, and written to film by means of a laser in order to recreate the recorded image. The first charge-coupled device detectors for KH-11 were developed by Westinghouse Electric Corporation at their Baltimore facility in the later 1970s. KH-11 Block II might have been the first reconnaissance satellite equipped for imaging with an CCD. Later block satellites may include signals intelligence capabilities and greater sensitivity in broader light spectrums.Communications
Communication to and data downloads from KH-11 satellites are routed through a constellation of communication relay satellites in higher orbits. The initial communications relay payload is believed to have operated at a frequency of 60 GHz, as radio emission at this frequency is blocked by Earth's atmosphere, and thus not detectable from the ground. Launch of the initial two Satellite Data System satellites occurred in June and August 1976, i.e. ahead of the first launch of a KH-11 satellite in late 1976.One of the initial on-orbit challenges were failures of the Traveling-wave tubes, which amplified the communications signals sent from the imaging satellite to the relay satellites, and from the relay satellites to the ground stations. During crossings of the ionosphere, ions could build up on the outside of the tubes, which were operated at 14,000 volts. This resulted in repeated sparking and deposition of carbon traces inside the tubes, ultimately shorting them out. The issue could be abated by changing the orbiting satellite's orientation during crossing of the ionosphere, and was finally solved by better shielding of the tubes in follow-up satellites.
Ground stations for the receipt of KH-11 data have been reported to be located in Fort Belvoir, VA, the former Buckley Air National Guard Base, CO, and Kapaun Air Station, Germany.
Resolution and ground sample distance
A perfect mirror observing in the visual spectrum has a diffraction limited resolution of around 0.05 arcsec, which from an orbital altitude of corresponds to a ground sample distance of. Operational resolution should be worse due to effects of the atmospheric turbulence. Astronomer Clifford Stoll estimates that such a telescope could resolve up to "a couple inches. Not quite good enough to recognize a face".KH-11 generations
Five generations of U.S. electro-optical reconnaissance have been identified:Block I
Block I refer to the original KH-11 satellite, of which five were launched between 19 December 1976 and 17 November 1982.Block II
The three Block II satellites are in the open literature referred to as KH-11B, the alleged DRAGON codename, or CRYSTAL, and are believed to be capable of taking infrared images in addition to optical observations. The first or second Block II satellite was lost in a launch failure.Block III
Four Block III satellites, commonly called KH-12 or Improved CRYSTAL were launched between November 1992 and October 2001. The name "Improved CRYSTAL" refers to the "Improved Metric CRYSTAL System". Metric describes the capability to fix Datum references in an image relative to the World Geodetic System for mapping purposes. Another improvement was an eightfold increase in the download rate compared to earlier models to facilitate improved real-time access and increased area coverage. From Block III on, the typical lifetime of the satellites increased to about 15 years, possibly related to a higher lift-off mass, which facilitates larger fuel reserves for countering atmospheric drag.Block IV
Three electro-optical satellites launched in October 2005, January 2011, and August 2013 are attributed to Block IV.Block V
A new generation of clandestine communications satellites launched to inclined geosynchronous orbits have led to speculations that these are in support of Block V electro-optical satellites scheduled for launch in late 2018 and 2021. The two satellites have been built by Lockheed Martin Space Systems, have a primary mirror with a diameter of 2.4 meters, and are evolutionary upgrades to the previous blocks built by Lockheed.Based on the published hazard areas for the launch, an orbital inclination of 74° has been deduced for NROL-71. This could indicate that NROL-71 is targeted for a Type II Multi Sun-Synchronous Orbit, which would enable the satellite to study the ground at a range of local hour effects.
Derivatives
The Misty satellite is believed to have been derived from the KH-11, but modified to make it invisible to radar, and hard to detect visually. The first Misty satellite, USA-53, was released by the on mission STS-36 in 1990. The USA-144 satellite, launched on 22 May 1999 by a Titan IVB from Vandenberg Air Force Base may have been a second Misty satellite, or an Enhanced Imaging System spacecraft. The satellites are sometimes identified as KH-12s.In January 2011, NRO donated to NASA two space Optical Telescope Assemblies with diameter primary mirrors, similar in size to the Hubble Space Telescope, yet with steerable secondary mirrors and shorter focal length. These were initially believed to be KH-11 series "extra hardware", but were later attributed to the cancelled Future Imaging Architecture program. The mirrors are to be used by NASA as the primary and spare for the Roman Space Telescope.