A newly released treasure trove of historical data reveals intriguing details about a secret Cold War project known as the Manned Orbiting Laboratory (MOL).

The U.S. Air Force's MOL program ran from December 1963 until its cancellation in June 1969. The program spent $1.56 billion during that time, according to some estimates.

While the program never actually lofted a crewed space station, those nearly six years were quite eventful, featuring the selection of 17 MOL astronauts, the remodeling of NASA's two-seat Gemini spacecraft, the development of the Titan-3C launch vehicle and the building of an MOL launch site at Vandenberg Air Force Base in California. [Photos: Declassified US Spy Satellite Photos & Designs]

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