Pregnant Guppy

NASA had a problem. The S-IVB rocket upper stage, the third stage of the Saturn V and second stage of Saturn IB launchers, was built in Sacramento, California, but launched from the Kennedy Space Center in Florida. The rocket stage was far too large to transport by road or rail, and the only option appeared to be on a barge via the Panama Canal, which was slow, expensive, and risky to the delicate lightweight structure of the rocket. But while the S-!VB was big (6.6 metre diameter and 17.8 metres long), it was light—just 13.5 tonnes. John Conroy, former Air Force fighter pilot, said “Why not fly it there?” and proposed modifying a retired 1950s piston powered Boeing 377 Stratocruiser to transport the stage. Thus was born with Pregnant Guppy which, with its successors, transported outsize cargo for NASA and eventually other customers for years. In fact, one Super Guppy, also built from a Boeing 377 but converted to turboprop power, which first flew in August 1965 remains in service today.

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