United States Air Force pilot from 1969 Earth who briefly encountered the U.S.S. Enterprise when the starship made an unscheduled trip back in time. Christopher was transported to the Enterprise for a short time following the accidental destruction of his airplane, but the dilemma for the future crew was that the pilot might pollute the historical timeline with his knowledge of future technologies. Fortunately, a way was discovered to return him to his craft and remove his knowledge of the future starship.

Christopher was father to a son, Shaun Geoffrey, who would later command the first successful Earth-Saturn probe.