Meeting the Challenge: The Hexagon KH-9 Reconnaissance Satellite First Edition

Phil Pressel and his colleagues at Perkin Elmer have created a marvelous story of the development of the camera system for the HEXAGON reconnaissance satellite, arguably the most complex system placed into earth orbit and an achievement that has played a crucial role in national security. The book suffers from careless editing, but this hardly detracts from the compelling narrative.Pressel describes the origin of the camera concept at Itek, and the transition of the concept to Perkin Elmer for development and production. Part of the Itek story is told in the book, "Spy Capitalism; Itek and the CIA" by Jonathan E. Lewis (Yale University Press, 2002). Itek was the successful developer of the cameras for the CORONA system for the CIA, the system that preceded HEXAGON. In 1965, the CIA awarded Itek a contract to develop the concept for a follow-on to CORONA, and Itek formed a project team led by Frank Madden, who had been the CORONA camera project manager.The Itek reference camera configuration for the CIA HEXAGON study (then code-named FULCRUM) included a rotating "optical bar" and film transport, much as described by Pressel. The scope of the CIA study contract included fabrication of prototype optical elements, development and test of a film transport to demonstrate synchronism of the film with the moving image, and initial design of a supporting structure and evaluation of interfaces with a satellite vehicle under development by Lockheed (who also provided the CORONA vehicle). The optical design included a 20-inch-diameter transparent corrector plate, a stiff beryllium flat folding mirror, and a primary imaging mirror of light-weight fused silica egg-crate construction; during polishing, one of the egg-crate ribs cracked. Itek completed a detailed analysis of the components of image motion at the imaging slit, constructed a brass board film transport including a "twister" to conform the film platen to the scan motion, and a "looper" to store film between frames permitting constant film velocity from supply and to take-up; test of the brass board demonstrated that the film motion could be synchronized to the scanned image motion within an acceptable tolerance. I was responsible for the vehicle interface study; since we were wary of film tracking risks, we chose to mount the film supply reels coaxially with the optical bars to minimize the length of the film path, and we configured a truss structure to support the optical bars and film supplies from three attachment points on the vehicle. We analyzed the response of the truss to launch dynamic loads, and the temperature response of the system to on-orbit thermal variations.Itek corporate managers (several of whom had been Air Force officers) were well aware of competition between the CIA and the Air Force for control of the satellite recon programs, and undertook a concurrent study for the Air Force of a camera designated S-2 meeting similar resolution objectives. Two S-2 cameras would be fixed to the satellite vehicle, with scan motion provided by two-surfaced rotating beryllium mirrors in front of the imaging optics. Because of the limited vehicle diameter, the focal length of the fixed optics was reduced to 73% of the FULCRUM optics focal length, which had the effect of reducing the image scale and requiring tighter tolerances on film motion and optical surfaces. In addition, the size of the scanning mirror became prohibitive at angles off-nadir of 45 degrees; this had the effect of reducing the scanned ground area relative to the 60-degree HEXAGON scan angle off nadir, and this reduced the frequency with which targets could be covered by the camera.The "Spy Capitalism" book recounts the two days that a government review team visited Itek for presentations on the alternate systems. At the conclusion of the reviews, the team adjourned to the Cambridge offices of Edwin Land, CEO of Polaroid and chairman of the review team. Eventually Itek management was invited into the meeting to receive its conclusions, and we on the HEXAGON project team were invited to wait in the ante-room outside the meeting. To our surprise, Itek management left the meeting and informed us that they declined to accept a contract to develop the HEXAGON system, recommending that the program continue with studies to refine the system requirements, designs, and program plans.Shortly we were directed to dismantle and pack the full-size camera mockup that we had constructed, pack the film transport brass board, and secure the files containing our project documentation. A few days later, a small fleet of moving vans appeared at our facility to load the packages and files and transport them with police escort to Connecticut. I was part of a team directed to travel to the Perkin Elmer plant to brief the P-E team on the results of our study. Thus ended Itek's former close relationship with the CIA on the CORONA program and our opportunity to expand Itek's sales factorially.Ironically, Itek's government business was subsequently bought by Litton Industries. When Litton was acquired by Northrop Grumman, the Itek Optical Systems Division was spun off to Hughes Aircraft. Les Dirks, who had advanced to Deputy Director of the CIA for Science and Technology, retired from government service and joined Hughes as Vice President for Planning; he instigated the acquisition of the Danbury operations of P-E, and combined their business with Itek. Raytheon then acquired Hughes, sold the optical business to Goodrich Corp., and sold the former Itek facility in Lexington, MA to the developer of an office condominium. Most lately, Goodrich was acquired by United Technologies, and the combined Itek and P-E business continues with headquarters in Danbury, CT.

As much as I'd like to read a definitive history of the KH-9 Hexagon photo-reconnaissance satellite, I'm sorry to say that "Meeting the Challenge" is not it.In fairness, though, it was not intended to be, so I'm reviewing the book that is, not the book that I wish it were."Meeting the Challenge" contains tons of fascinating technical and programmatic information about the design, development, test and operations of Perkin-Elmer's photographic payload. But there's little coverage of the rest of the Hexagon system--the spacecraft itself, the "buckets," the launch vehicle, on-orbit operations, film processing and interpretation, etc. It's about the camera system and not much else. It's a part of the story, but not the whole thing.In comparison with today's high-performance, solid-state digital optical systems (space-based or otherwise), Hexagon's film cameras seem hopelessly archaic, even though they were state-of-the-art when the system was developed and flown. Just imagine a satellite as big as a school bus carrying up to 60 miles of photographic film. The pressurized film path was over 100 feet long, with hundreds of beryllium rollers. While the two rotating stereo cameras scanned the earth below, the film passed across their focal planes at exactly the right speed and angle for blur-free photography. Hexagon's film-handling system seems like a mechanical and electrical nightmare, far too complicated for mere humans to understand. Yet Hexagon had an almost perfect success record in 19 missions between 1971 and 1984 (the program ended on a sad note when the last Hexagon's Titan 34D booster exploded just after liftoff on April 18, 1986).While "Meeting the Challenge" gave me an in-depth understanding of many parts of Hexagon's camera payload, it left me puzzled about the key technical feature that made the whole system feasible: the "twister." I still don't understand how this mechanical device was able to interface between a rotating camera lens, an oscillating platen and a moving strip of film to assure sharp photos. An appendix includes the twister's patent, but only the drawings. There's no textual explanation of how the danged thing worked, nor any identification of the numbered parts on the drawings. Until I grok the twister I feel that I don't really know Hexagon, and I'm not there yet. BTW, Googling it did not help either.As a collection of reminiscences of Perkin-Elmer people who worked on the program, "Meeting the Challenge" lacks stylistic, organizational and editorial unity. It's often repetitious, the level of detail about the various parts of the system varies wildly and in some places the personal stories may be a little off-topic. Still, it fills a void in the history of U.S. reconnaissance satellites, and for that alone it belongs on every space enthusiast's bookshelf.My four-star rating reflects five stars for content (despite the lingering mystery of the twister), and three for presentation.

Mr. Pressel's book is one of those rare peeks behind the curtain, a privileged look at the development of one of the most impressive optical camera systems ever devised. The author does an excellent job of describing the performance requirements of the spy agency customer and the technical challenges involved in delivering a reliable operational system. The HEXAGON was designed and built before the days of digital imaging and processing; it used photographic film. This is a fascinating tale of trial and error, imaginative innovation, of agency and contractor rivalries, personalities in conflict and personal resolve. HEXAGON was indeed a remarkable asset, a wonder of engineering. As more works become available now that HEXAGON has been declassified, Mr. Pressel's contributions and this volume of his recollections while working on the program will continue to be valued.

I was surprised that this book came out so quickly after the declassification of the KH-9 HEXAGON program. Sure enough, it turns out to be mostly written years ago when everything about the program was Top Secret. With no access to original documents, the author had to rely totally on the memories of his fellow workers. Even the detailed technical drawings in the book were reconstructed from memory!The result is a worm's-eye view of the KH-9 camera system from the factory floor at Perkin-Elmer, with virtually no information about the operational side of the program. Even the spacecraft is very poorly covered because it was fabricated by Lockheed. People who want more than a chatty memoir should skip this book and wait for a comprehensive history (which I'm sure someone is researching right now).

Excellent ouvrage sur le système de prise de vue du KH9/Hexagon. C'est l'ultime aboutissement de la série des satellites de reconnaissance type Discoverer/Corona avec capsules récupérables. Le développement de ce matériel s'est fait d'abord au début des années 60 avec moults difficultés avec les systèmes KH1, KH2 & KH3, puis petit à petit la technologie s'est affinée à travers les systèmes KH4A & KH4B, KH5/Argon et KH6/Lanyard. Après cela le programme a pris de l'ampleur avec KH7 Gambit-1 et KH8/Gambit-2 pour aboutir au fameux 'Big Bird' alias KH9.Cela a continué avec les engins de type KH-11 et autres en adoptant une autre technologie, mais cela est une autre histoire!...Jihemess.