KH-9A, HEXAGON and KH-9B, HEXAGON RECONNAISSANCE IMAGING SPACERAFT
“Big Bird”
By © Charles P. Vick 2007 All Rights Reserved05-24-07
Disclaimer
The opinions and evaluations stated here in are only the author’s and cannot be construed to reflect those of any Government agency, company, institute or association. It is based on public information, circumstantial evidence, informed speculation, and declassified U.S. intelligence community documents, official US government documents and histories, oral histories, interviews and engineering analysis. As with all data regarding the intelligence programs of the US intelligence community, this analysis is subject to revision--and represents a work in progress.
KH-9 “Big Bird”
KH-9 was a big step forward for US space reconnaissance capabilities. The camera system consisted of two cameras with 60 inch lenses, able to operate individually or together to produce stereoscopic images. The cameras could cover an area of 80 by 360 miles at a resolution of two feet. The KH-9 also included four film capsules, and included some infrared film at the end of the reel, to provide experimental capability to see through cloud cover and expose camouflage.
The ability of the KH-9 to photograph huge chunks of territory was a delight to the newly created Defense Mapping Agency (DMA). The fewer photos needed to cover a part of the world, the easier it was to construct an accurate map.
The first KH-9 was placed in an elliptical orbit 114 by 186 miles, with a 96.41 degree inclination on June 15, 1971 . This orbit was sun-synchronous, so that each daylight pass was made at an identical sun angle, eliminating differences in shade angles on separate passes.
Following missions had increasing lifetimes, and through the 1970's the US had nearly uninterrupted satellite reconnaissance capability, which greatly aided enforcement of arms control treaties with the Soviet Union and also provided crucial intelligence in the buildup to the 1973 Yom Kippur war.
Statistical Summary on KH-9
"The statistical summary of the KH-9/HEXAGON program showed 19 successful launches in 20 attempts. For those 19 successful launches, the KH-9 spacecraft operated with a mean inclination of 96.4 degrees, mean perigee of 101 miles, and a mean apogee of 159 miles. The mean lifetime of the 19 missions was 138 days. The actual lifetime grew significantly within the first three years of the program, going from lifetimes between 50 and 100 days to well over 100 days. Over the next ten years, the lifetimes of the KH-9 missions grew even further, moving from 158 up to 275 before the short 115-day final mission of 1984." (Richelson, J. America's Secret Eyes in Space . Harper and Row, 1990. page 211).
Film Imagery Optical Systems Design
It is known that it used two 60 inch diameter primary mirrors but in what configuration was the issue. The various optical designs could consist of two large rotating oil drum like short folding image telescopes camera’s variation on the CORONA design or two side by side base overlapping 60 inch primary mirrors using a common oddly shaped barrel Hubble like telescopes or two high resolution folding image KH-8 stripped down optical bar camera’s used inn high altitude low resolution mode to all fit within the 10 diameter and length of the spacecraft launch shroud design requirements. This web site illustrates through its various scematics shows the variations reverse design studies which perhaps mimics to some degree the various design considerations from the known design data of the spacecraft. The last of the three designs of two stripped down side by side KH-8 optical bar camera’s is the most predominately displayed in KH-9 revealed designs as well as concepts of the subsequent KH-10, DORIAN – Manned Orbital Laboratory (MOL) payload design studies. Besides the rotating oil drum camera design the two side by side overlapping Hubble like Perkins Elmera Camera telescopes offered better optical resolution from a higher orbital altitude than previously available with the precursor systems. In all cases the spacecraft imaging systems were required to provide overlapping front and back images of the same area of interest for stereo views. Ultimately the reader is left to guess which optical systems design was adopted for the KH-9 spacecraft series.
Chart II: Optical Swath Data Parameters for Imaging 06-27-04
By Charles P. Vick 2004 All Rights Reserved
| Spacecraft, Designation, Resolution | Average Orbital Perigee | Swath “Footprint” | Half Swath Base Length | Off Nadir Maximum View Angle | Elevation From Target to Satellite | Range to Target from Satellite |
| *Known | Kilometers | Kilometers | Kilometers | Degrees | Degrees | kilometers |
| HEXAGON KH-9 A & B Low Resolution
Mapping Camera |
162.3481*
162.3481* |
562.3738 x 37.2330 Same film as KH-7 & KH-8 (80 by 360 miles?)
59.42 x 29.71 |
381.1869 | 30 x 2=60 total swath | 30 | 324.6962 (325 limit) |
1. The KH-9 imaging capability had known limits of 30 degrees elevation from the target or 60 degrees off nadir angle which yields a 120 degrees swath potential imaging area capability. The KH-9 imaging system apparently used the same KH-7, 8 film used in the CORONA format. The wider frames provided for higher resolution Hexagon images.
References:
1. McDowell, Jonathan, US Reconnaissance Satellite Programs, Part-1, Quest, Summer 1995 pp. 22-33
2. SSB Satellite Support Bus, Lockheed Missile & Space Company pp. 1-20
3. Commercial Titan-III Users Manuel
4. Bus-1 Implementation Concept for Space Station Alpha, Lockheed Missile & Space Company, Inc., Nov. 25, 1993.,ppp1-4, 17-31, 64.
5. Day, Dwayne Allen, Sensitivity About Gambit And Hexagon Imagery Declassification, History of the Gambit and Hexagon Programs, The Recon Report September 20, 2000, FPSpace, Aug. 30, 2000.
6. Quick Facts about the KH-7 and KH-9 Mapping Imagery
7. Declassified MOL and Gemini – B design details & Declassified MOL Baseline Configuration studies
8. Day, Dwayne A., A Failed Phoenix: The KH-6 LANYARD Reconnaissance Satellite, Spaceflight, Vol. 39, May 1997, pp. 170-174.
9. KH-6 Camera System declassified NPIC document February 1963.
10. Day, Dwayne A, Pushing Iron Spaceflight, Vol. 46, July 2004, pp. 289-293.
