WASHINGTON -- Time has taken its toll on the 56 men credited with helping establish the discipline of national space reconnaissance 40 years ago.

Some have died, taking the story of their top-secret work to the grave. Others are too ill to travel. One asked the government not to identify him at all.

Former Secretary of Defense William Perry (right) pictured here with Army Gen. John Shalikashvili (left), chairman of the Joint Chiefs of Staff, helped advise the NSA and CIA on how to use the NRO's data.

• James Baker, Harvard astronomer. Designed most of the lenses and many of the cameras used in aerial over flights of "denied territory," enabling the success of the U.S. peacetime strategic reconnaissance policy.
• Lee Battle, Jr., Air Force colonel. Directed the government and contractor team that produced, launched and operated the world's first satellite recovery system.
• John Bennett, TRW chief engineer. Conceived the spacecraft design, including reflectors, used in CIA signals-intelligence satellite systems.
• John Browning, Air Force colonel (deceased). Directed a key Air Force signals-intelligence satellite project, managing its launch and operations.
• Jon Bryson, Air Force colonel. Directed the development, acquisition and operation of an Air Force signals-intelligence satellite system that handled rapidly increasing data rates.
• Roy Burks, CIA. Managed combined team of Air Force, CIA and contractors on the CORONA project.
• Frank Buzard, Air Force colonel. Headed an Air Force imaging satellite program described as the most complex electromechanical device ever put in orbit.
• Cornelius "Connie" Chambers, Lockheed. Contributed flight "protective measures" adopted for use on most NRO satellites.
• John Copley, Air Force colonel. Guided development of Air Force signals-intelligence satellites from the earliest experiments to later constellations that provided broader coverage.
• Robert Crotser, Lockheed. Wrote the handbook on cost and schedule management that remains a standard reference in spacecraft acquisition.
• John Crowley, CIA (deceased). Established a true partnership between the CIA and Defense Department elements of the NRO.
• James de Broekert, Advent Systems. Contributed key payload designs for several first-generation Air Force signals-intelligence satellites.
• Gary Geyer, Air Force colonel. Improved signals-intelligence collection, data processing and distribution that allowed data to reach military and civilian users in near real-time.
• Thomas Haig, Air Force colonel. Led team that developed operational polar-orbiting meteorological satellite, its launch vehicle and ground stations.
• Frederick Kaufman, TRW. Directed team that produced first communications cross-link systems in space.
• Robert Kohler, CIA. Introduced photographic edge-measurement and edge-sharpening tools used to improve overhead imagery.
• Ellis Lapin, Aerospace Corporation. Managed system design and engineering effort for Air Force imaging satellites that nearly doubled their functional time in orbit.
• Lloyd Lauderdale, CIA (deceased). Managed CIA team that developed an advanced signals intelligence system.
• Richard Leghorn, Itek Corporation. Pushed peacetime strategic reconnaissance and founded company that produced the lenses and cameras for the CORONA and other satellite systems.
• Walter Levison, Itek Corporation (deceased). Designed the camera for CORONA and other satellite programs.
• Howard Lorenzen, Naval Research Laboratory (deceased). Directed the development of GRAB, the nation's first signals-intelligence satellite.
• Frank Madden, Itek Corporation. Directed the design, testing and production of the CORONA camera and its improved versions.
• James Mannen, Air Force colonel. Introduced procedures that improved targeting of satellites and increased their photographic resolution.
• Paul Mayhew, TRW. Managed two signals-intelligence satellite systems.
• Reid Mayo, Naval Research Laboratory. Conceived and designed the first Navy signals-intelligence satellite, GRAB/DYNO, and later served as project engineer and technical director of Navy satellite reconnaissance program.
• James Morgan, Navy (deceased). Developed targeting and data distribution guidelines for key Navy satellite reconnaissance programs.
• Mark Morton, General Electric. Directed team that designed, built and tested reentry capsules used in the CORONA film-return satellite and other programs.
• Alden Munson Jr., Aerospace Corporation and TRW. Conceived and built a fully automatic electronic intelligence system to support U.S. troops in the field.
• Charles Murphy, Air Force colonel. Served as the first technical director of the CORONA Advanced Projects Integration Facility, the project's main link to the U.S. intelligence community.
• Frederic "Fritz" Oder, Air Force colonel. Directed the nation's first reconnaissance satellite project, the Air Force WS-117L (later SAMOS) in the late 1950s.
• Julius "Val" Peline, Lockheed. Served as test director and program manager for a key imagery-intelligence satellite program.
• Robert Powell, Lockheed. Devised a novel orbital maneuver that greatly extended the lifetimes of satellites on orbit.
• Edward Reese, General Electric. Led the development of the ground-data system that processed digital imagery from electro-optical imaging satellites.
• Osmond "Ozzie" Ritland, Air Force major-general (deceased). Managed the U-2 spy plane program, which made overflights of the Soviet Union possible.
• Lee Roberts, Air Force colonel (deceased). Directed improvements in a key Air Force satellite reconnaissance effort that produced high-resolution imagery of Earth's surface.
• Charles Roth, CIA (deceased). Served as the CIA manager of a government-industry team that produced the first electro-optical-imaging reconnaissance satellite system.
• Robert Roy, Air Force colonel. Directed NRO launch operations at Vandenberg Air Force Base.
• Charles Spoelhof, Eastman Kodak. Worked on the design of the U-2, A-12 and SAMOS cameras and directed efforts that led to the use of thin-based Mylar film in NRO reconnaissance satellites.
• Forrest Stieg, CIA. Devised a process for selecting an optimum orbit that balanced signals collection with satellite longevity.
• Marvin Stone, TRW. Served as a payload systems engineer and project manager on CIA electronic intelligence satellite programs.
• Don Tang, Lockheed. Established a "collection scale" for determining what signals could be technically collected at affordable costs.
• Albert "Bud" Wheelon, CIA. Served as first director of the CIA's Directorate of Science and Technology and was responsible for U-2 overflights and the development of four satellite reconnaissance systems.
• Peter Wilhelm, Naval Research Laboratory. Invented new techniques and devices that improved the performance of signals-intelligence satellites.
• Roy Worthington, Air Force colonel. Directed the integration and launch of some 200 satellites from the Western Test Range.
• Robert Yundt, Air Force colonel. Directed an Air Force team that introduced a new, long-lived, multi-purpose signals-intelligence satellite.

• William Baker, AT&T Bell Laboratories. Served as scientific counselor to the National Security Agency, CIA, Navy and NRO on overhead reconnaissance systems.
• Merton Davies, RAND. Invented a rotating, panoramic camera and worked on designs for a family of film-based reconnaissance satellites that led to CORONA.
• Sidney Drell, theoretical physicist and presidential advisor. Served as a key scientific consultant to the CIA's satellite reconnaissance program and was instrumental in securing congressional approval for several NRO special projects.
• Richard Garwin, physicist and presidential advisor. Established standards and found solutions for electro-mechanical design of modern spacecraft.
• Amrom Katz, RAND (deceased). Performed the first experimental simulation of electro-optical satellite imaging and co-directed projects that eventually led to CORONA.
• James Killian, Massachusetts Institute of Technology (deceased). Served as MIT president and chaired the panel that recommended building the U-2 aircraft and reconnaissance satellites.
• Edwin "Din" Land, Polaroid (deceased). Served as CEO of Polaroid, advised President Nixon on the capabilities of electro-optical imaging and advised NRO of new and existing overhead systems.
• Frank Lehan, presidential advisor (deceased). Instrumental in the decision to proceed with an important high-altitude signals-intelligence satellite system and contributed to the reflector design for that system.
• William Perry, former Secretary of Defense. Advised the National Security Agency and the CIA on programs to intercept and evaluate Soviet missile telemetry and communications intelligence.
• Edward Purcell, Harvard Nobel Laureate (deceased). Developed methods to make reconnaissance satellites difficult, if not impossible to observe with radar.