KH-11 KENNEN
Template:Short description Template:Use American English Template:Use dmy dates
The KH-11 KENNEN<ref name="NRO20160322">Template:Cite web Template:PD-notice</ref><ref name="TSR20120130">Template:Cite web</ref><ref name="CIA-RDP83M00914R000700040112-1">Template:Cite web Template:PD-notice</ref><ref name="CIA-RDP74B00415R000100010065-5">Template:Cite web Template:PD-notice</ref> (later renamed CRYSTAL,<ref name="Richelson">Template:Cite bookp.199-200</ref> then Evolved Enhanced CRYSTAL System, and codenamed 1010<ref name="Yenne">Template:Cite book</ref>Template:Rp and Key Hole<ref name="Yenne"/>Template:Rp) is a type of reconnaissance satellite first launched by the American National Reconnaissance Office (NRO) 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.<ref>Template:Cite web Template:PD-notice</ref>
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.<ref name="FY2013NIP">Template:Cite web Template:PD-notice</ref> 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.<ref>Template:Cite book</ref>
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;Template:Citation needed images of Sudan and Afghanistan made public in 1998 related to the response to the 1998 U.S. embassy bombings;<ref name="MERVIN 2000 pp. 770–776">Template:Cite journal</ref> and a 2019 photo, provided by then-President Donald Trump,Template:R 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.<ref name="day20170130">Template:Cite web</ref>
The Film Read-Out KH-7 GAMBIT (FROG) served as NRO Program A's competitor to NRO Program B's initial electro-optical imagery (EOI) satellite.<ref>National Reconnaissance Office. GAMBIT and HEXAGON Programmatic Declassification Guidance 23 June 2011 Released by NRO on 7 March 2012</ref> After a precursor EOI study under the codeword Zoster, President Nixon on 23 September 1971 approved the development of an EOI satellite codenamed Zaman.<ref>Template:Cite web Template:PD-notice</ref> In November 1971, this codeword was changed to Kennen, which is Middle English for "to perceive".<ref>Template:Cite web Template:PD-notice</ref><ref>Template:Cite web Template:PD-notice</ref> Initial director of the ZAMAN/KENNEN Program Group was Charles R. "Charlie" Roth; he was succeeded in October 1975 by Rutledge P. (Hap) Hazzard.<ref>Template:Cite web</ref>
The KENNEN system transmits its imagery as data through the Satellite Data System (SDS), a network of communications satellites.<ref name="Richelson" /><ref>Template:Cite web</ref> These digital images were initially processed at a secret National Reconnaissance Office facility dubbed Area 58 at Fort Belvoir in Virginia.<ref>Template:Cite web Template:PD-notice</ref><ref name="associatepublishers_quasar">Template:Cite web</ref>
In 1999, NRO selected Boeing as the prime contractor for the Future Imagery Architecture (FIA) 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.<ref name="DN20090602">Template:Cite web</ref> USA-224, the first of these, was launched in early 2011 two years ahead of the initial schedule estimate.<ref name="NRO20110907">Template:Cite web Template:PD-notice</ref>
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 Template:Cvt 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.<ref name=Allen_19741127>Template:Cite web Template:PD-notice</ref>
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 Template:Convert.<ref name="Richelson"/><ref name=Wade>Template:Cite web</ref> A NASA history of the Hubble,<ref>The Power to Explore Template:Webarchive NASA in particular, Chapter XII – The Hubble Space Telescope Template:Webarchive Chapter 12, p. 483 Template:PD-notice</ref> in discussing the reasons for switching from a 3-meter main mirror to a Template:Convert 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,<ref name=NYTimes19850113>Template:Cite web</ref> i.e. about Template:Cvt. Later blocks are believed to have a mass of around Template:Cvt<ref name=FA8811-19-R-0002>Template:Cite web Template:PD-notice</ref> to Template:Cvt.<ref>Template:Citation</ref><ref name="Richelson"/>
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.<ref name=NYTimes19850113/> It has been speculated that the propulsion module is related to Lockheed's Satellite Support Bus (SSB), which had been derived from the Satellite Control Section (SCS) developed by Lockheed for KH-9.<ref name=TheSpaceReview20110207>Template:Cite web</ref>
Optical Telescope Assembly
A CIA history states that the primary mirror on the first KH-11s measured Template:Convert, but sizes increased in later versions.<ref name="Richelson"/> 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.<ref name=GJTenet20000927>Template:Cite web Template:PD-notice</ref>
Later satellites had larger mirrors, with a diameter of around Template:Convert.<ref>Template:Cite web</ref> 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.Template:Citation needed
Imaging sensors and camera modes
The initial KH-11 camera system offered frame and strip modes.<ref>Template:Cite web Template:PD-notice</ref> 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 (several hundred diodes per inch) 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.<ref name="COS099312">Template:Cite web Template:PD-notice</ref> The first charge-coupled device (CCD) detectors for KH-11 were developed by Westinghouse Electric Corporation at their Baltimore facility in the later 1970s.<ref name=OralHistoriesRobertKohler>Template:Cite web</ref> KH-11 Block II might have been the first reconnaissance satellite equipped for imaging with an Template:Nowrap CCD.<ref>globalsecurity.org – KH-11 KENNAN 24 April 2007</ref> Later block satellites may include signals intelligence capabilities and greater sensitivity in broader light spectrums (probably into infrared).<ref name="CBOPublication528">Template:Cite web Template:PD-notice</ref>
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.<ref name=TheSpaceReview20180267>Template:Cite web</ref> 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.<ref name=OralHistoriesRobertKohler/> 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.<ref name= HistoricalDictAirIntel>Template:Cite book</ref>
Resolution and ground sample distance
A perfect Template:Convert mirror observing in the visual spectrum (i.e. at a wavelength of 500 nm) has a diffraction limited resolution of around 0.05 arcsec, which from an orbital altitude of Template:Cvt corresponds to a ground sample distance of Template:Cvt. Operational resolution should be worse due to effects of the atmospheric turbulence.<ref>Template:Cite journal</ref> Astronomer Clifford Stoll estimates that such a telescope could resolve up to "a couple inches. Not quite good enough to recognize a face".<ref name="stoll1989">Template:Cite book</ref>
KH-11 generations
Five generations of U.S. electro-optical reconnaissance have been identified:<ref name="sfr20090622">Template:Cite web</ref><ref name="nsf20110120">Template:Cite web</ref>
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.<ref name="GS20070424"/> The first or second Block II satellite was lost in a launch failure.<ref name="nsf20110120"/>
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" (IMCS). Metric describes the capability to fix Datum references (markings) in an image relative to the World Geodetic System for mapping purposes.<ref>Template:Cite web</ref><ref name="F-2019-00076_C05119876">Template:Cite web Template:PD-notice</ref> Another improvement was an eightfold increase in the download rate compared to earlier models to facilitate improved real-time access and increased area coverage.<ref>Template:Cite web</ref> 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.<ref name="seesat_Dec-2018_0058">Template:Cite web</ref>
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 (NROL-71) and 2021 (NROL-82).<ref>Template:Cite web</ref> 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.<ref name="spacenews_20091020">Template:Cite web</ref>
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,<ref name="MSSO_20181207">Template:Cite web</ref> which would enable the satellite to study the ground at a range of local hour effects (shadow direction and length, daily activities, etc.).<ref name="seesat_Dec-2018_0040">Template:Cite web</ref><ref name="nsfw_20181207">Template:Cite web</ref>
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 Template:OV 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,<ref>Template:Cite web</ref> 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 Template:Convert diameter primary mirrors,<ref name="WP20120604">Template:Cite web</ref><ref name="NYT20120604">Template:Cite news</ref><ref name="Dressler20120604">Template:Cite web</ref><ref>Template:Cite web</ref> similar in size to the Hubble Space Telescope, yet with steerable secondary mirrors and shorter focal length (resulting in a wider field of view). These were initially believed to be KH-11 series "extra hardware", but were later attributed to the cancelled Future Imaging Architecture program.<ref>Template:Cite web</ref> The mirrors are to be used by NASA as the primary and spare for the Roman Space Telescope.
Compromises
In 1978, a young CIA employee named William Kampiles was accused of selling a KH-11 System Technical Manual describing design and operation to the Soviets. Kampiles was convicted of espionage and initially sentenced to 40 years in prison.<ref>Template:Cite web</ref><ref>Template:Cite web Template:PD-notice</ref> Later, this term was reduced, and after serving 18 years, Kampiles was released in 1996.<ref name="jonathonpollard_kampiles">Template:Cite web</ref><ref name="bop_kampiles">Template:Cite web Template:PD-notice</ref>
In 1984 Samuel Loring Morison, an intelligence analyst at the Naval Intelligence Support Center, forwarded three classified images taken by KH-11 to the publication Jane's Defence Weekly. In 1985, Morison was convicted in Federal Court on two counts of espionage and two counts of theft of government property, and was sentenced to two years in prison.<ref>Template:Cite news</ref> He was pardoned by President Clinton in 2001.<ref name=lewis>Template:Cite news</ref>
In 2019 Donald Trump, as President of the United States, tweeted a classified image of the aftermath of a failed test of Iran's Safir rocket,<ref name=brumfiel20190830>Template:Cite web</ref> which some believe was taken from the USA-224 satellite.<ref>Template:Cite web</ref><ref>Template:Cite news</ref>
In Seymour Hersh's book The Samson Option: Israel's Nuclear Arsenal & American Foreign Policy Ari Ben-Menashe says that Israel had stolen images from the KH-11 in order to target missiles at the Soviet Union.<ref>Template:Cite book</ref>
KH-11 missions
Nine KH-11 satellites were launched between 1976 and 1990 aboard Titan-3D and Titan-34D launch vehicles, with one launch failure. For the following five satellite launches between 1992 and 2005, a Titan IV launch vehicle was used. The three most recent launches since 2011 were carried out by Delta IV Heavy launch vehicles. The KH-11 replaced the KH-9 film return satellite, among others, the last of which was lost in a liftoff explosion in 1986.
All KH-11 satellites are in either of two standard planes in Sun-synchronous orbits. As shadows help to discern ground features, satellites in a standard plane east of a noon/midnight orbit observe the ground at local afternoon hours, while satellites in a western plane observe the ground at local morning hours.<ref name="GS20070425">Template:Cite web</ref><ref name="satobs20090713">Template:Cite web</ref><ref name="SatTrackCam1">Template:Cite web</ref> Historically launches have therefore been timed to occur either about two hours before or one hour after local noon (or midnight), respectively.<ref name="nsf20110120"/> The orbits are such that ground-tracks repeat after a certain number of days, currently each four days for the primary satellites in the East and West orbital plane.<ref name="SatTrackCam2">Template:Cite web</ref>
The constellation consists of two primary and two secondary satellites (one primary and one secondary per plane). The orbital planes of the two primary satellites in the East and West plane are separated by 48° to 50°. The orbital plane of the secondary satellite in the East plane is located 20° to the east of the primary satellite, while the orbital plane of the secondary satellite in the West plane is located 10° to the west of the primary satellite.<ref name="SatTrackCam2"/><ref name="SatTrackCam3">Template:Cite web</ref>
| Name | KH-11 Block<ref name="satobs20090713"/> |
Launch date | COSPAR ID<ref>Jonathan's Space Report: List of satellite launches</ref> SATCAT No. |
Launch designation | Orbit | Plane<ref name="satobs20090713"/> | Orbital decay date |
|---|---|---|---|---|---|---|---|
| OPS 5705 | 1-1 | 19 December 1976 | 1976-125A <ref>Template:Cite web Template:PD-notice</ref> 09627 |
N/A | Template:Cvt i=96.9° |
West | 28 January 1979 |
| OPS 4515 | 1-2 | 14 June 1978 | 1978-060A <ref>Template:Cite web Template:PD-notice</ref> 10947 |
Template:Cvt i=96.8° |
West | 23 August 1981 | |
| OPS 2581 | 1-3 | 7 February 1980 | 1980-010A <ref>Template:Cite web Template:PD-notice</ref> 11687 |
Template:Cvt i=97.1° |
East | 30 October 1982 | |
| OPS 3984 | 1-4 | 3 September 1981 | 1981-085A <ref>Template:Cite web Template:PD-notice</ref> 12799 |
Template:Cvt i=96.9° |
West | 23 November 1984 | |
| OPS 9627 | 1-5 | 17 November 1982 | 1982-111A <ref>Template:Cite web Template:PD-notice</ref> 13659 |
Template:Cvt i=96.9° |
East | 13 August 1985 | |
| USA-6 | 2-1 | 4 December 1984 | 1984-122A <ref>Template:Cite web Template:PD-notice</ref> 15423 |
Template:Cvt i=98° <ref name="GS20070424">Template:Cite web</ref> |
West | 10 November 1994 | |
| Unknown | 2-2 | 28 August 1985 | N/A | Failed to orbit | East | N/A | |
| USA-27 | 2-3 | 26 October 1987 | 1987-090A <ref>Template:Cite web Template:PD-notice</ref> 18441 |
Template:Cvt, i=98° <ref name="GS20070424"/> | East | 11 June 1992 | |
| USA-33 | 2-4 | 6 November 1988 | 1988-099A <ref>Template:Cite web Template:PD-notice</ref> 19625 |
Template:Cvt, i=98° <ref name="GS20070424"/> | West | 12 May 1996 | |
| USA-86 | 3-1 | 28 November 1992 | 1992-083A <ref>Template:Cite web Template:PD-notice</ref> 22251 |
Template:Cvt, i=97.7° <ref name="USA-86">Template:Cite web</ref> | East | 5 June 2000 | |
| USA-116 | 3-2 | 5 December 1995 | 1995-066A <ref>Template:Cite web Template:PD-notice</ref> 23728 |
Template:Cvt, i=97.7° <ref name="USA-116">Template:Cite webTemplate:Dead link</ref> | East | 19 November 2008 | |
| USA-129 | 3-3 | 20 December 1996 | 1996-072A <ref>Template:Cite web Template:PD-notice</ref> 24680 |
NROL-2 | Template:Cvt, i=97.7° <ref name="USA-129">Template:Cite web</ref> | West | 24 April 2014 <ref name="MarcoLangbroek20140521">Template:Cite web</ref> |
| USA-161 | 3-4 | 5 October 2001 | 2001-044A <ref>Template:Cite web Template:PD-notice</ref> 26934 |
NROL-14 | Template:Cvt, i=97.9° <ref name="USA-161">Template:Cite web</ref> | East | late 2014 <ref name="MarcoLangbroek20160630">Template:Cite web</ref> |
| USA-186 | 4-1 | 19 October 2005 | 2005-042A<ref>Template:Cite web Template:PD-notice</ref> 28888 |
NROL-20 | Template:Cvt, i=97.9° <ref name="USA-186">Template:Cite web</ref> | West | |
| USA-224 | 4-2 | 20 January 2011 | 2011-002A <ref>Template:Cite web Template:PD-notice</ref> 37348 |
NROL-49 | Template:Cvt, i=97.9° <ref name="USA-224">Template:Cite web</ref> | East | |
| USA-245 | 4-3 | 28 August 2013 | 2013-043A <ref>Template:Cite web Template:PD-notice</ref> 39232 |
NROL-65 | Template:Cvt, i=97.9° <ref name="USA-245">Template:Cite web</ref> | West | |
| USA-290 | 5-1? | 19 January 2019 | 2019-004A <ref>Template:Cite web Template:PD-notice</ref> 43941 |
NROL-71 | Template:Cvt, i=73.6° <ref name="USA-290">Template:Cite web</ref> | N/A | |
| USA-314 | 5-2? | 26 April 2021 | 2021-032A <ref>Template:Cite web Template:PD-notice</ref> 48247 |
NROL-82 | Template:Cvt, i=98.0° <ref name="USA-314">Template:Cite web</ref> | East | |
| USA-338 | 5-3? | 24 September 2022 | 2022-117A<ref>Template:Cite web</ref> 53883 |
NROL-91 | Template:Cvt, i=73.6° <ref name="USA-338">Template:Cite web</ref> | N/A |
KH-11 satellites require periodic reboosts to counter atmospheric drag, or to adjust their ground track to surveillance requirements. Based on data collected by amateur observers, the following orbital characteristics of OPS 5705 were calculated by amateur skywatcher Ted Molczan.<ref name="MSNBC201008">Template:Cite web</ref>
| OPS 5705 Time period |
Perigee (AMSL) |
Apogee (AMSL) |
Apogee at end of period (AMSL) |
|---|---|---|---|
| 19 December 1976 – 23 December 1976 | Template:Cvt | Template:Cvt | Template:Cvt |
| 23 December 1976 – 27 March 1977 | Template:Cvt | Template:Cvt | Template:Cvt |
| 27 March 1977 – 19 August 1977 | Template:Cvt | Template:Cvt | Template:Cvt |
| 19 August 1977 – January 1978 | Template:Cvt | Template:Cvt | Template:Cvt |
| January 1978 – 28 January 1979 | Template:Cvt | Template:Cvt | Deorbited |
On 4 September 2010, amateur astrophotographer Ralf Vandebergh took some pictures of a KH-11 (USA-129) satellite from the ground. The pictures, despite being taken with a Template:Cvt aperture telescope from a range of Template:Convert, show major details such as dishes and solar panels, as well as some elements whose function is not known.<ref>Template:Cite web</ref>
Cost
Estimated unit costs, including launch and in Template:Year dollars, range from Template:US$Template:NbsptoTemplate:NbspTemplate:US$Template:Nbspbillion (inflation adjusted Template:US$Template:NbsptoTemplate:NbspTemplate:US$Template:Nbspbillion in Template:Inflation-year).<ref name="CBOPublication528"/>
According to US Senator Kit Bond initial budget estimates for each of the two legacy KH-11 satellites ordered from Lockheed in Template:Year were higher than for the latest Nimitz-class aircraft carrier (CVN-77)<ref name="DN20090602"/> with its projected procurement cost of Template:US$Template:Nbspbillion as of MayTemplate:NbspTemplate:Year.<ref name="NHC20050525">Template:Cite web</ref> In Template:Year, after the launch of USA-224, DNRO Bruce Carlson announced that the procurement cost for the satellite had been Template:US$Template:Nbspbillion under the initial budget estimate, which would put it at about Template:US$Template:Nbspbillion (inflation adjusted Template:US$Template:Nbspbillion in Template:Inflation-year).<ref name="NRO20110907"/>
In April Template:Year, the NRO assigned a "worth more than Template:US$Template:Nbspbillion" to the final two legacy KH-11 satellites.<ref name="NROPR201402">Template:Cite web Template:PD-notice</ref>
Image gallery
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A KH-11 Block 1 image of a Xian H-6 jet bomber operated by China.
-
The 2nd KH-11 Block 1 image of the construction of a Kiev-class aircraft carrier leaked to Jane's in 1984.
-
A U.S. reconnaissance satellite image of the Al-Shifa pharmaceutical factory, attributed to KH-11 Block 3.
-
A KH-11 Block 2 image of the Zhawar Kili camp in Afghanistan.
See also
References
- Aviation Week, 25 October 2005, p. 29
Further reading
- John Pike (2000-09-07) program Federation of American Scientists Retrieved 2008-02-23
- John Pike (1 January 1997) KH-11 product Federation of American Scientists Retrieved 24 April 2004
- John Pike (9 September 2000) KH-12 Improved Crystal Federation of American Scientists Retrieved 23 April 2004
- John Pike (22 August 1998) KH-12 product Federation of American Scientists Retrieved 23 April 2004
- Mark Wade (9 August 2003) KH-11 Encyclopedia Astronautica Retrieved 23 April 2004
External links
Template:National Reconnaissance Office Template:NRO satellites Template:US Reconnaissance Satellites