Dave McDowell must have had an air of mystery about him during his decades as an engineer at Eastman Kodak.
His neighbors, his friends, and even his family had no idea what he was working on, and Dave couldn't tell them, even though they had a lot of questions.
"Constantly, constantly," he recalled. "It was fun at parties sometimes; you would know the other people that were cleared, or had a pretty good idea of who they were, and you would talk in sort of coded words, 'Where are you working? I'm over at Lincoln Plant, Unit 7.' "