Meeting the Challenge: The Hexagon Reconnaissance Satellite is the recently declassified story of the design, development, production, and operation of the Hexagon KH-9 reconnaissance satellite. It provided invaluable photographic intelligence to the United States government, and it stands as one of the most complicated systems ever put into space. In 1965 CIA Director John McCone issued the call for a satellite with unparalleled technical requirements that could visually map most of the landmass of the earth, photograph selected areas of interest, and return the resulting film safely to Earth. Developed by the Perkin-Elmer Corporation and operated between 1971 and 1986 Hexagon was the last film-based orbiting photo-reconnaissance satellite.This engineering marvel features the following achievements: the world's largest spherical thermal vacuum chamber used to test the system; the development and use of new and sophisticated electronics, such as LED's and brushless motors; the ability to precisely control the synchronization of film traveling at up to 200 inches per second at the focal plane, on a rotating camera, mounted in a moving vehicle and focused on a moving earth; sixty miles of film used on each mission; and, stereo photography of the entire surface of the earth. When film captured by the satellite was sent back to earth it launched in a film-return capsule which was snagged by an aircraft as it parachuted downward upon reentering the earth's atmosphere. In 1972 a film bucket containing sensitive images sank to the bottom of the Pacific Ocean, resulting in a daring rescue three miles underwater by the U.S. Navy's submergence vehicle Trieste II. Featuring both technical details and historical anecdotes, former Perkin-Elmer engineer Phil Pressel has written the definitive account of this important chapter in U.S. intelligence and aerospace history.