Part of our comprehensive series on the National Reconnaissance Office (NRO) and its "spy satellite" network, this volume covers the Hexagon photoreconnaissance satellite flown between 1971 and 1986. The previously classified documents in this collection were released by the NRO in September 2011 as part of its 50th anniversary. In declassifying these fascinating documents, the NRO has opened the curtain to show the tremendous challenges that were overcome to achieve the impressive successes that help win the Cold War. Hexagon, with its multiple recovery buckets and extended mission life, moved the U.S. closer to achieving continuous space imaging capability. Hexagon's primary panoramic camera provided improved search coverage and resolution. Hexagon's mapping camera provided global geodetic positioning, accurate point locations for military operations, and data for military targeting. At precisely 10:41 A.M., Pacific Standard Time, on June 15, 1971, the first of America's fourth generation photographic reconnaissance satellites (Hexagon program) lifted off a pad at the Vandenberg Air Force Base in southern California. This event was the result of 57 months of intensive effort to design, manufacture, and assemble a revolutionary new intelligence collection system, thousands of scientists, engineers, technicians, and administrators in various government and industrial facilities throughout the United States were involved in making it happen. Here is an excerpt from one of the documents about Hexagon: "During its 13-year life, HEXAGON provided a unique collection capability which may never again be achieved by US imagery satellites. Its ability to cover thousands of square nautical miles with contiguous, cloud-free, high-resolution imagery in a single operation* provided US intelligence users and mapping, charting, and geodesy (MC&G) organizations with vast amounts of nearly simultaneous contiguous coverage. Order-of-battle information across entire Soviet military di