Taming Liquid Hydrogen - NASA's History Office

hydrogen-oxygen in the upper stages of the Saturn V was the significant technical decision that
enabled the United States to achieve the first manned lunar landing,” he said. “The Russian effort
to accomplish this mission without high-energy upper stages was doomed to failure.” 71
The decision of the Silverstein committee directly influenced the fortunes of Centaur. Centaur
moved into NASA’s mainstream as a stepping-stone to a piloted lunar landing. However, the von
Braun team, although convinced of the superiority of liquid-hydrogen upper stages, was never fully
committed to Centaur. Referring to the new designation of Centaur as the final stage (or S-V stage)
for the Saturn C-1, Krafft Ehricke joked that on top of Saturn’s “horrible tower,” at least there would
be one “decent vehicle.” He referred to the Saturn C-1 as the “Centaur-tipped Saturn,” to which
von Braun retorted, “Centaur-tipped Saturn, Hell!” 72
Von Braun favored large, heavy structures to ensure reliability. His conservative design
philosophy, which Ehricke derided as comparable to the Brooklyn Bridge in its conservatism,
“mitigated against the use of liquid hydrogen which, more than conventional fuels, depended
upon very light structures to help offset the handicap of low density.” 73 Though von Braun
agreed to Saturn stages powered by liquid hydrogen, he apparently did not approve of
Centaur’s balloon structure. His opposition may have influenced the NASA decision to award
the contract for the S-IV second stage to the Douglas Aircraft Company, ostensibly to provide
“some semblance of competition” among aerospace companies. 74 The S-IV second stage, with
its cluster of six RL10 engines, produced an additional 90,000 pounds of thrust to the
1,296,000 pounds of thrust generated by the first stage. The choice of Douglas was controversial
enough to merit an investigation by the GAO, since Douglas had no prior experience with
liquid hydrogen. 75 Douglas avoided the balloon structure by adopting a honeycomb design
similar to that of the Douglas Thor missile.
Caught Between DOD and NASA
Centaur’s Origins in Atlas 25
From July 1960 to early 1962, the Air Force continued to manage both the Centaur and the Agena
programs, reporting to Marshall Space Flight Center. D. L. Forsythe, the Agena program chief,
71 See note 68.
72 Interview with Krafft Ehricke by John Sloop, 26 April 1974, NASA Historical Reference Collection.
73 John Sloop, Liquid Hydrogen, 208. See also G. R. Richards and Joel W. Powell, “The Centaur Vehicle,” Journal of the
British Interplanetary Society 42 (1989): 99–120.
74 J. D. Hunley, The Birth of NASA, 129. See also Ray A. Williamson, “The Biggest of Them All, Reconsidering the
Saturn V,” in To Reach the High Frontier, 304.
75 Ray Williamson, “Access to Space: Steps to the Saturn V,” in John M. Logsdon et al., Exploring the Unknown, Volume
IV, Accessing Space (Washington, DC: NASA SP-4407): 1–31.