using the same engines as a third stage. The C-1 would become the C-2 upon insertion of a new S-III stage with two new to thrust engines, keeping the S-IV and Centaur on top. The C-3 was a similar adaptation, inserting the S-II stage with four of the same 150-200,000 lbf thrust engines, keeping the S-III and S-IV stages of the C-2, but eliminating the Centaur. The first stage of the C-3 would also be increased to over by either replacing the four center H-1 engines with one F-1 engine, or uprating all eight H-1 engines. Examining the results strongly suggested that the C models were the only ones worth proceeding with, as they offered much higher performance than any other combination and offered great flexibility by allowing the stages to be mixed-and-matched for any particular launch need. Additionally, by developing the rocket in a building-block manner maximum vehicle reliability would be achieved as each new stage is added to already tested and proven stages. Thus the decision came down not to performance, which was clearly settled, but development risk. The Saturn had always been designed to be as low-risk as possible, the only really new components being a minor upgrade to the engine for the lower stage and the Centaur as the upper stage. Developing entirely new hydrogen-burning stages for the entire "stack" would increase the risk that a failure of any one of the components could disrupt the entire program. But as the Committee members noted: "If these propellants are to be accepted for the difficult top-stage applications, there seems to be no valid engineering reasons for not accepting the use of high-energy propellants for the less difficult application to intermediate stages." von Braun was won over; development of the current design would continue as a back-up, but the future of the Saturn was based on hydrogen and was tailored solely to NASA's requirements. On the last day of 1959, NASA Administrator T. Keith Glennan approved the Silverstein recommendations. Chances of meeting the schedule improved with two Eisenhower administration decisions in January 1960. The Saturn project received a DX rating, which designated a program of highest national priority, which gave program managers privileged status in securing scarce materials. More important, the administration agreed to NASA's request for additional funds. The Saturn FY 1961 budget was increased from $140 million to $230 million. On 15 March 1960 President Eisenhower