KH-9 Hexagon

KH-9 (BYEMAN codename HEXAGON), commonly known as Big Bird or KeyHole-9,^[1] was a series of photographic reconnaissance satellites launched by the United States between 1971 and 1986. Of twenty launch attempts by the National Reconnaissance Office (NRO), all but one were successful.^[2] Photographic film aboard the KH-9 was stored on RCA Astro Electronic Division take up reel system then sent back to Earth in recoverable film return capsules for processing and interpretation. The highest ground resolution achieved by the main cameras of the satellite was 2 ft (0.61 m),^[3] though another source says "images in the "better-than-one-foot" category" for the last "Gambit" missions.^[4]

KH-9 HEXAGON

A KH-9 HEXAGON during assembly by Lockheed
Mission type	Imagery intelligence
Operator	National Reconnaissance Office
Spacecraft properties
Manufacturer	Lockheed (satellite vehicle) Perkin-Elmer (main camera) Itek (stellar and terrain cameras) Eastman Kodak (film) General Electric (MK V reentry vehicles) McDonnell Douglas (MK 8 reentry vehicles)
Launch mass	11400 kg to 13300 kg (with mapping camera)
Dimensions	16.2 m × 3.05 m (53.1 ft × 10.0 ft)
Start of mission
Rocket	Titan III
Launch site	Vandenberg Air Force Base, SLC-4E
Contractor	Martin Marietta
Orbital parameters
Reference system	Sun-synchronous orbit
Regime	Low Earth orbit
Perigee altitude	170 km (110 mi)
Apogee altitude	260 km (160 mi)
Inclination	97°
Main telescope
Type	folded Wright camera
Diameter	0.91 m (3 ft 0 in)
Focal length	1.52 m (5 ft 0 in)
Focal ratio	f/3.0
Wavelengths	visible light, Near-infrared
Instruments SPC Stereo Panoramic Cameras MCS Mapping Camera System SI Stellar Index camera S3 Stellar Solid State Camera

A KH-9 HEXAGON main features

They are also officially known as the Broad Coverage Photo Reconnaissance satellites (Code 467), built by Lockheed Corporation for the NRO.^[1]

The satellites were an important factor in determining Soviet military capabilities and in the acquisition of accurate intelligence for the formulation of U.S. national policy decisions as well as deployment of U.S. forces and weapon systems. The satellites were instrumental in U.S. National Technical Means of Verification of Strategic Arms Limitation Talks (SALT) and the Anti-Ballistic Missile Treaty (ABMT).^[5]

The KH-9 was declassified in September 2011 and an example was put on public display for a single day on 17 September 2011 in the parking lot of the Steven F. Udvar-Hazy Center of the National Air and Space Museum.^[6][7][8]

On 26 January 2012, the National Museum of the United States Air Force put a KH-9 on public display along with its predecessors the KH-7 and KH-8.^[9]

Development

KH-9 was, according to many who worked on it, the most sophisticated mechanical satellite in history.^[10] It was conceived in the early 1960s as a replacement for the CORONA search satellites. The goal was to search large areas of the Earth with a medium resolution camera. The KH-9 carried two main cameras, although a mapping camera was also carried on several missions. The photographic film from the cameras was sent to recoverable re-entry vehicles and returned to Earth, where the capsules were caught in mid-air by an aircraft. Four re-entry vehicles were carried on most missions, with a fifth added for missions that included a mapping camera.

Between September 1966 and July 1967, the contractors for the Hexagon subsystems were selected. Lockheed Missiles and Space Company (LMSC) was awarded the contract for the Satellite Basic Assembly (SBA), Perkin Elmer for the primary Sensor Subsystem (SS), McDonnell for the Reentry Vehicle (RV), RCA Astro-Electronics Division for the Film Take-Up system, and Itek for the Stellar Index camera (SI). Integration and ground-testing of Satellite Vehicle-1 (SV-1) were completed in May 1971, and it was subsequently shipped to Vandenberg Air Force Base in a 70 ft (21 m) container. Ultimately, four generations ("blocks") of KH-9 HEXAGON reconnaissance satellites were developed. KH9-7 (missions 7 to 12) was the first to fly a Block-II panoramic camera and SBA. Block-III (missions 13 to 18) included upgrades to electrical distribution and batteries. Two added tanks with ullage control for the Orbit Adjust System (OAS) and new thrusters for the Reaction Control System (RCS) served to increase KH-9's operational lifetime. In addition, the nitrogen supply for the film transport system and the camera vessel was increased. Block-IV (missions 19 and 20) was equipped with an extended command system using plated-wire memory.^[11] In the mid 1970s, over 1,000 people in the Danbury, Connecticut area worked on the secret project.^[12]

A reentry vehicle from the first Hexagon satellite sank to 16,000 ft (4,900 m) below the Pacific Ocean after its parachute failed. The USS Trieste II (DSV-1) retrieved its payload in April 1972 after a lengthy search, but the film had disintegrated during the nine months underwater, leaving no usable photographs.^[13]

Over the duration of the program, the lifetime of the individual satellites increased steadily. The final KH-9 operated for 275 days. The satellite mass with and without the Mapping Camera System was 13,300 and 11,400 kg (29,300 and 25,100 lb), respectively.

NRO intended to replace HEXAGON with ZEUS, later DAMON—HEXAGON's camera flown on the Space Shuttle—but DAMON was canceled in December 1980.^[10][14] In December 1976 NRO launched the first KH-11 KENNEN. While its electro-optical digital imaging had a smaller field of view than HEXAGON, by not needing film KENNEN was usable for years.^[10]

Main KH-9 components

Satellite Control Section

Satellite Control Section

The Satellite Control Section (SCS), which forms the aft part of the SBA, started as Air Force Project 467. SCS was intended as a more capable replacement for the on-orbit propulsion, which had been provided by the Agena upper stage for previous generations of reconnaissance satellites. The SCS featured an increased diameter of 10 ft (3.0 m) (compared to 5 ft (1.5 m) for the Agena) and a length of 6 ft (1.8 m). It housed hydrazine propellant tanks for the pressure fed Orbital Adjust System (OAS) and the Reaction Control System (RCS). OAS and RCS were connected by a transfer line to facilitate propellant exchange. The tank pressure was maintained within the operational range by additional high pressure nitrogen tanks. The SCS incorporated a freon gas system for backup attitude control inherited from the Agena, commonly referred to as "lifeboat".^[15] SCS was equipped with deployable solar panels and an unfurlable parabolic antenna for high data rate communication.^[16]

Main camera

A main camera optical path

A achieved ground resolution of Satellite Vehicles (SV) 1 to 18 main cameras.

A KH-9 image of the Soviet Kubinka airfield

The main camera system was designed by Perkin-Elmer to take stereo images,^[17] with a forward looking camera on the port side, and an aft looking camera on the starboard side. Images were taken at altitudes ranging from 90–200 mi (480,000–1,060,000 ft; 140–320 km). The camera optical layout is an f/3.0 folded Wright camera, with a focal length of 60 in (1,500 mm). The system aperture is defined by a 20 in (510 mm) diameter aspheric corrector plate, which corrects the spherical aberration of the Wright design. In each of the cameras the ground image passes through the corrector plate to a 45°-angle flat mirror, which reflects the light to a 0.91 m (3 ft 0 in)-diameter concave main mirror. The main mirror directs the light through an opening in the flat mirror and through a four-element lens system onto the film platen. The cameras could scan contiguous areas up to 120° wide, and achieved a ground resolution better than 2 ft (0.61 m) during the later phase of the project.^[3][18] Dwayne Allen Day calculated, using disclosed specifications, that HEXAGON was capable of 0.2 m (7.9 in) at nadir, and 0.4 m (1 ft 4 in) at apogee.^[10]

Mapping camera

Missions 1205 to 1216 carried a "mapping camera" (also known as a "frame camera") that used 9 in (230 mm) film and had a moderately low resolution of initially 30 ft (9.1 m), which improved to 20 ft (6.1 m) on later missions ^[19] (somewhat better than LANDSAT). Intended for mapmaking, photos this camera took cover the entire Earth with images between 1973 and 1981.^[20] Almost all the imagery from this camera, amounting to 29,000 images, each covering 3,400 km² (1,300 sq mi), was declassified in 2002 as a result of Executive order 12951,^[21] 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.^[22]

Scientific analysis of declassified KH-9 satellite images continues to reveal historic trends and changes in climate and terrestrial geology. A 2019 study of glacial melt in the Himalayas over the past half-century used data collected by KH-9 satellites throughout the 1970s and 1980s to demonstrate that melt rates had doubled since 1975.^[23]

The KH-9 was never a backup project for the KH-10 Manned Orbital Laboratory. It was developed solely as a replacement for the Corona search system.^[15]

Reentry vehicles

The forward section of KH-9 housed four McDonnell Douglas Mark 8 satellite reentry vehicles (RV), which were fed film exposed by the main cameras. Each RV had an empty mass of 434 kg. It housed a film take-up assembly (built by RCA Astro Electronic Division) with a mass of 108 kg, and could store about 227 kg of film. The twelve mapping missions were equipped with an additional General Electrics Mark V RV, which could store about 32 kg of film for a total mass of 177 kg.^[15]

High-altitude atmospheric density

Missions 1205 to 1207 carried Doppler beacons^[24] to help map the atmospheric density at high altitudes in an effort to understand the effect on ephemeris predictions.^[25][26] The measurements of the atmospheric density were released through NASA.^[27]

ELINT subsatellites

Stereo pair of KH-9 imagery (Los Angeles-1968/06)

Missions 1203, 1207, 1208, 1209, and 1212 to 1219 included Ferret ELINT sub-satellites, which were launched into a high Earth orbit to catalogue Soviet air defence radars, eavesdrop on voice communications, and tape missile and satellite telemetry. Missions 1210 to 1212 also included scientific subsatellites.^{[28][29][30][31][32][33][34][35][36]}

IRCB (S73-7)

IRCB (Infra-Red Calibration Balloon) was an 66 cm diameter inflatable calibration sphere orbited in the Space Test Program. It was a piggy-back payload on KH9-8 (1208) boosting it to a 500 mile (800 kilometers) circular orbit. It disappeared from ground-based sensors in the 1990s, and was found again in 2024.^[37][38]

KH-9 missions

Name	Block [11]	Mission no.	Launch date	NSSDC ID NORAD #	Other Name	Launch vehicle	Orbit	Decay date
KH9-1	I	1201	15 June 1971	1971-056A [39] 05297	OPS 7809	Titan IIID	184.0 km × 300.0 km, i=96.4°	6 August 1971 [39]
KH9-2	I	1202	20 January 1972	1972-002A [40] 05769	OPS 1737	Titan IIID	157.0 km × 331.0 km, i=97.0°	29 February 1972 [40]
KH9-3	I	1203	7 July 1972	1972-052A [41] 06094	OPS 7293	Titan IIID	174.0 km × 251.0 km, i=96.9°	13 September 1972 [41]
KH9-4	I	1204	10 October 1972	1972-079A [42] 06227	OPS 8314	Titan IIID	160.0 km × 281.0 km, i=96.5°	8 January 1973 [42]
KH9-5	I	1205	9 March 1973	1973-014A [43] 06382	OPS 8410	Titan IIID	152.0 km × 270.0 km, i=95.7°	19 May 1973 [43]
KH9-6	I	1206	13 July 1973	1973-046A [44] 06727	OPS 8261	Titan IIID	156.0 km × 269.0 km, i=96.2°	12 October 1973 [44]
KH9-7	II	1207	10 November 1973	1973-088A [45] 06928	OPS 6630	Titan IIID	159.0 km × 275.0 km, i=96.9°	13 March 1974 [45]
KH9-8	II	1208	10 April 1974	1974-020A [46] 07242	OPS 6245	Titan IIID	153.0 km × 285.0 km, i=94.5°	28 July 1974 [46]
KH9-9	II	1209	29 October 1974	1974-085A [47] 07495	OPS 7122	Titan IIID	162.0 km × 271.0 km, i=96.7°	19 March 1975 [47]
KH9-10	II	1210	8 June 1975	1975-051A [48] 07918	OPS 6381	Titan IIID	157.0 km × 234.0 km, i=96.3°	5 November 1975 [48]
KH9-11	II	1211	4 December 1975	1975-114A [49] 08467	OPS 4428	Titan IIID	157.0 km × 234.0 km, i=96.7°	1 April 1976 [49]
KH9-12	II	1212	8 July 1976	1976-065A [50] 09006	OPS 4699	Titan IIID	159.0 km × 242.0 km, i=97.0°	13 December 1976 [50]
KH9-13	III	1213	27 June 1977	1977-056A [51] 10111	OPS 4800	Titan IIID	155.0 km × 239.0 km, i=97.0°	23 December 1977 [51]
KH9-14	III	1214	16 March 1978	1978-029A [52] 10733	OPS 0460	Titan IIID	172.0 km × 218.0 km, i=96.4°	11 September 1978 [52]
KH9-15	III	1215	16 March 1979	1979-025A [53] 11305	OPS 3854	Titan IIID	177.0 km × 256.0 km, i=96.3°	22 September 1979 [53]
KH9-16	III	1216	18 June 1980	1980-052A [54] 11850	OPS 3123	Titan IIID	169.0 km × 265.0 km, i=96.5°	6 March 1981 [54]
KH9-17	III	1217	11 May 1982	1982-041A [55] 13170	OPS 5642	Titan IIID	177.0 km × 262.0 km, i=96.4°	5 December 1982 [55]
KH9-18	III	1218	20 June 1983	1983-060A [56] 14137	OPS 0721	Titan 34D	163.0 km × 224.0 km, i=96.4°	21 March 1984 [56]
KH9-19	IV	1219	25 June 1984	1984-065A [57] 15063	USA 2	Titan 34D	170.0 km × 230.0 km, i=96.5°	18 October 1984 [57]
KH9-20	IV	1220	18 April 1986	1986-F03	Launch failed [2]	Titan 34D	—	—

(NSSDC ID Numbers: See COSPAR)

Cost

The total cost of the 20 flights KH-9 program from FY1966 to FY1986 was US$3.262 billion in respective year dollars (equivalent to 17.47 billion in 2023, with an average reference year of 1976).^[11]

Specifications

Data source: The Encyclopedia of US Spacecraft ^[1] and NSSDC

• Launch vehicle: Titan IIID/34D
• Total weight: 11,400 kg (25,100 lb), with mapping camera 13,300 kg (29,300 lb)
• Reentry weight: 5,330 kg (11,750 lb) ^[58]
• Max. diameter (main body): 3.05 m (10.0 ft) ^[58]
• Length (with mapping camera): 16.21 m (53.2 ft)^[58]
• Orbit: elliptical, 160 km × 240 km (99 mi × 149 mi)
• Scanners: television, radio, and high resolution camera

Declassification

The HEXAGON images have been declassified in 2011 as a continuation of Executive Order 12951. ^[59][60] The declassified imagery has since been used by a team of scientists from Dartmouth College to detect Roman forts in Syria, ^[61] and the Catalan Institute of Classical Archaeology (ICAC) to detect qanat irrigation systems. ^[62]

Gallery

• 
  The reaction control system of a KH-9, showing the propellant tanks.
• 
  A KH-9 in scaffolding, being prepared for launch.
• 
  A technician despools one of the re-entry modules which contained the film used by the cameras.
• 
  A diagram showing the assembly, testing and launch preparations of a KH-9.
• 
  The forward section of a KH-9.
• 
  A KH-9 re-entry module hanging from its parachute, ready to be retrieved.
• 
  Another view of the KH-9's reaction control system.
• 
  A KH-9 being transported by truck in a special canister.
• 
  The shroud and base of a KH-9 undergo vibration tests in an acoustic chamber.
• 
  This painting of a KH-9 shows the two different camera types that the satellite carried.
• 
  Basic specifications and diagram of the KH-9.
• 
  This diagram shows the various sections of the KH-9 and their dimensions.
• 
  A KH-9 at the National Museum of the United States Air Force (front view).
• 
  A KH-9 at the National Museum of the United States Air Force (forward section).
• 
  A KH-9 at the National Museum of the United States Air Force (film recovery unit).
• 
  A KH-9 at the National Museum of the United States Air Force (center section).
• 
  A KH-9 at the National Museum of the United States Air Force (left camera).
• 
  A KH-9 at the National Museum of the United States Air Force (rear view without solar panels).

See also

• Spaceflight portal

Other U.S. imaging spy satellites:

• CORONA series:
  • KH-1
  • KH-2
  • KH-3
  • KH-4
• KH-5 Argon
• KH-6 Lanyard
• KH-7 Gambit
• KH-8 Gambit 3
• KH-10 (Manned Orbiting Laboratory)
• KH-11 Kennen
• KH-13 (Enhanced Imaging System)

References

1. Yenne, Bill (1985). The Encyclopedia of US Spacecraft. Exeter Books (A Bison Book), New York. ISBN 0-671-07580-2. p.32 Big Bird
2. "34D-9: Titan rocket with last KH-9 explodes after liftoff (18 April 1986) (F)". 16 December 2012. Archived from the original on 21 December 2021 – via YouTube.
3. Gerald K. Haines (1997). "Critical to US Security: the development of the GAMBIT and HEXAGON satellite reconnaissance system". National Reconnaissance Office (NRO). Archived from the original on 15 September 2012. Retrieved 24 September 2011. This article incorporates text from this source, which is in the public domain.
4. Deutsch, Ricky (12 November 2020). "Controlling Hexagon". Retrieved 19 April 2022.
5. "Assessment of Intelligence Gain Provided by KH-9 over KH-4 and KH-8" (PDF). NRO. Retrieved 7 January 2023. This article incorporates text from this source, which is in the public domain.
6. "NRO Observes 50th Anniversary with Declassification".
7. "Declassified US Spy Satellites Reveal Rare Look at Secret Cold War Space Program". Space.com. 18 September 2011.
8. Doyle, John M., Big Bird, uncaged, Air and Space, December 2011/January 2012, p.10
9. Cohen, Aubrey, "Three former spy satellites go on display" Seattle Post-Intelligencer 26 January 2012
10. Day, Dwayne Allen (30 January 2017). "Black ZEUS: The top secret shuttle mission that never flew". The Space Review. Retrieved 29 October 2024.
11. "The HEXAGON story" (PDF). National Reconnaissance Office (NRO). 1988. Archived from the original (PDF) on 16 September 2012. Retrieved 6 October 2011. This article incorporates text from this source, which is in the public domain.
12. "Decades Later, a Cold War Secret Is Revealed". Fox News. Associated Press. 25 December 2011.
13. Walthrop, David (28 May 2013). "An Underwater Ice Station Zebra: Recovering a Secret Spy Satellite Capsule from 16,400 feet Below the Pacific Ocean" (PDF). CIA (Historical Collection Publications). Archived from the original (PDF) on 28 October 2013. Retrieved 29 June 2013. This article incorporates text from this source, which is in the public domain.
14. Day, Dwayne Allen (1 July 2019). "Top Secret DAMON: the classified reconnaissance payload planned for the fourth space shuttle mission". The Space Review. Retrieved 29 October 2024.
15. Burnett, M.G. (1 December 1982). "Hexagon (KH-9) Mapping Camera Program and Evolution" (PDF). NRO. Retrieved 12 May 2021.
16. Hall, R. Cargill (1988). "The Air Force and the National Security Space Program 1946 - 1988" (PDF). USAF Historical Research Center. This article incorporates text from this source, which is in the public domain.
17. Doyle, John M., Big Bird, uncaged, Air & Space, December 2011/January 2012, p.10
18. Richard J. Chester (1985). "A history of the HEXAGON program". National Reconnaissance Office (NRO). Archived from the original on 15 September 2012. Retrieved 24 September 2011. This article incorporates text from this source, which is in the public domain.
19. "NRO's Review & Redaction Guide (RRG), Version 2, 2012" (PDF). NRO. Retrieved 7 January 2023. This article incorporates text from this source, which is in the public domain.
20. NARA ARC database description of "Keyhole-9 (KH-9) Satellite Imagery", accession number NN3-263-02-011
21. "National Archives Releases Recently Declassified Satellite Imagery". National Archives and Records Administration press release. 9 October 2002. This article incorporates text from this source, which is in the public domain.
22. "NIMA Sponsors Historical Imagery Declassification Conference America's Eyes: What We Were Seeing". SpaceRef. 15 October 2002. Archived from the original on 14 May 2023. Retrieved 8 January 2018.
23. Harvey, Chelsea (20 June 2019). "Cold War Spy Satellites Reveal Substantial Himalayan Glacier Melt". Scientific American. Retrieved 20 June 2019.
24. Barbara Pope (28 April 2006). "NIMS file by satellite name". NASA. This article incorporates text from this source, which is in the public domain.
25. James N. Bass; Krishin H. Bhavnani; Isabel M. Hussey (1 April 1975). "Atmospheric Density Determination from Analysis of Doppler Beacon Satellite Data". Air Force Cambridge Research Labs, Hanscom AFB. Archived from the original on 17 July 2011. Retrieved 16 January 2011. This article incorporates text from this source, which is in the public domain.
26. K. S. W. Champion; J. M. Forves (1976). "Atmospheric drag analyses of low-altitude Doppler beacon satellites". Satellite Doppler Positioning. 1. New Mexico State University: 343. Bibcode:1976sdp..conf..343C.
27. Scott F. Large (9 October 2002). "National Reconnaissance Office Review and Redaction Guide: Version 1.0 2008 Edition". NRO. Archived from the original on 6 May 2009. This article incorporates text from this source, which is in the public domain.
28. "1972-052C". NASA. 8 October 2010. This article incorporates text from this source, which is in the public domain.
29. "1973-088B". NASA. 8 October 2010. This article incorporates text from this source, which is in the public domain.
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34. "1976-065C". NASA. 8 October 2010. This article incorporates text from this source, which is in the public domain.
35. "1984-065C". NASA. 8 October 2010. This article incorporates text from this source, which is in the public domain.
36. Day, Dwayne (27 April 2009). "Robotic ravens: American ferret satellite operations during the Cold War". thespacereview.com.
37. Krebs, Gunter Dirk. "IRCB (S73-7)". Gunter's Space Page. Retrieved 5 May 2024.
38. Passant Rabie / Gizmodo (1 May 2024). "A satellite that was lost in space for 25 years has finally been found". Qz.com. Retrieved 5 May 2024.
39. "KH 9-01 1971-056A". NASA. 8 October 2010. This article incorporates text from this source, which is in the public domain.
40. "KH 9-02 1972-002A". NASA. 8 October 2010. This article incorporates text from this source, which is in the public domain.
41. "KH 9-03 1972-052A". NASA. 8 October 2010. This article incorporates text from this source, which is in the public domain.
42. "KH 9-04 1972-079A". NASA. 8 October 2010. This article incorporates text from this source, which is in the public domain.
43. "KH 9-05 1973-014 A". NASA. 8 October 2010. This article incorporates text from this source, which is in the public domain.
44. "KH 9-06 1973-046A". NASA. 8 October 2010. This article incorporates text from this source, which is in the public domain.
45. "KH 9-07 1973-088A". NASA. 8 October 2010. This article incorporates text from this source, which is in the public domain.
46. "KH 9-08 1974-020A". NASA. 8 October 2010. This article incorporates text from this source, which is in the public domain.
47. "KH 9-09 1974-085A". NASA. 8 October 2010. This article incorporates text from this source, which is in the public domain.
48. "KH 9-10 1975-051A". NASA. 8 October 2010. This article incorporates text from this source, which is in the public domain.
49. "KH 9-11 1975-114A". NASA. 8 October 2010. This article incorporates text from this source, which is in the public domain.
50. "KH 9-12 1976-065A". NASA. 8 October 2010. This article incorporates text from this source, which is in the public domain.
51. "KH 9-13 1977-056A". NASA. 8 October 2010. This article incorporates text from this source, which is in the public domain.
52. "KH 9-14 1978-029A". NASA. 8 October 2010. This article incorporates text from this source, which is in the public domain.
53. "KH 9-15 1979-025A". NASA. 8 October 2010. This article incorporates text from this source, which is in the public domain.
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57. "1984-065A 1984-065A". NASA. 8 October 2010. This article incorporates text from this source, which is in the public domain.
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59. Executive Order 12951
60. USGS (2017), USGS EROS Archive - Declassified Data - Declassified Satellite Imagery - 3 [Dataset], U.S. Geological Survey
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External links

• US Geological Survey Satellite Images: Photographic imagery from KH-7 Surveillance and KH-9 Mapping system (1963 to 1980).
• SpaceRef.com: "KH-9 Hexagon Spy Satellite Makes a Rare Public Outing (Photos and Video)"