He began his civilian career with the Navy in 1951 at the David Taylor Model Basin, in Carderock, Maryland, a leading design and testing facility for Navy ships. He participated in some of the early work on nuclear submarines before he was named chief scientist in 1958 of what was then called the Special Projects Office.
Under the general supervision of Navy Vice Adm. William Raborn, Craven led a team that, in 1960, successfully fired a Polaris missile from a submerged submarine. It was considered a landmark military development of the Cold War, but it was only one part of Craven’s innovative work with the Navy.
“I had five or six programs going,” he told the Honolulu Star-Bulletin in 2002. “One was multiheaded, so highly classified that nobody on it could tell relatives or anybody. They couldn’t even speculate who else was involved in the program. It was a special top secret program, which meant it didn’t exist.”