von Braun returned the design to DoD in December 1957 as "A National Integrated Missile and Space Vehicle Development Program", outlining the new design, then known simply as "Super-Jupiter". Several variations were proposed, using a common clustered first stage, and upper stages based on either the Atlas or Titan I. ABMA favored the Titan as the Atlas production was extremely high-priority and there was little or no excess capacity to spare. They proposed using the existing Titan tooling at diameter, but lengthening it to produce a new -long stage. A Centaur would be used as a third stage, which was expected to be ready for operational use in 1963, right when the lower two stages would have completed their testing. The resulting three-stage design was much taller and skinnier than the Saturn design that was eventually built.