Captain Atom was Nathaniel Christopher Adam, a United States Air Force officer of the Vietnam War era. Adam had been framed for a crime he didn't commit and sentenced to death under the watch of Col. Wade Eiling in 1968. As an alternative to execution, he was invited to participate in a military experiment with little chance of survival, in exchange for a presidential pardon. The experiment involved testing the hull of a crashed alien ship's durability by exploding a super nuclear bomb under it. Adam survived as the metal melted into his body and the excess energy threw him forward in time nearly twenty years (not incidentally, this coating with alien metal gave the revised character a full-body silvered metal look distinctly different from his previous incarnations).