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Monday, January 16, 2012

Reading List: The Saturn V F-1 Engine

Young, Anthony. The Saturn V F-1 Engine. Chichester, UK: Springer Praxis, 2009. ISBN 978-0-387-09629-2.
The F-1 rocket engine which powered the first (S-IC) stage of the Saturn V booster, which launched all of the Apollo missions to the Moon and, as a two stage variant, the Skylab space station, was one of the singular engineering achievements of the twentieth century, which this magnificent book chronicles in exquisite detail. When the U.S. Air Force contracted with Rocketdyne in 1958 for the preliminary design of a single chamber engine with between 1 and 1.5 million pounds of thrust, the largest existing U.S. rocket engine had less than a quarter the maximum thrust of the proposed new powerplant, and there was no experience base to provide confidence that problems such as ignition transients and combustion instability which bedevil liquid rockets would not prove insuperable when scaling an engine to such a size. (The Soviets were known to have heavy-lift boosters, but at the time nobody knew their engine configuration. In fact, when their details came to be known in the West, they were discovered to use multiple combustion chambers and/or clustering of engines precisely to avoid the challenges of very large engines.)

When the F-1 development began, there was no rocket on the drawing board intended to use it, nor any mission defined which would require it. The Air Force had simply established that such an engine would be adequate to accomplish any military mission in the foreseeable future. When NASA took over responsibility for heavy launchers from the Air Force, the F-1 engine became central to the evolving heavy lifters envisioned for missions beyond Earth orbit. After Kennedy's decision to mount a manned lunar landing mission, NASA embarked on a furious effort to define how such a mission could be accomplished and what hardware would be required to perform it. The only alternative to heavy lift would be a large number of launches which assembled the Moon ship in Earth orbit, which was a daunting prospect at a time when not only were rockets famously unreliable and difficult to launch on time, but nobody had ever so much as attempted rendezvous in space, no less orbital assembly or refuelling operations.

With the eventual choice of lunar orbit rendezvous as the mission mode, it became apparent that it would be possible to perform the lunar landing mission with a single launch of a booster with 7.5 million pounds of sea level thrust, which could be obtained from a cluster of five F-1 engines (which by that time NASA had specified as 1.5 million pounds of thrust). From the moment the preliminary design of the Saturn V was defined until Apollo 11 landed on the Moon, the definition, design, testing, and manufacturing of the F-1 engine was squarely on the critical path of the Apollo project. If the F-1 did not work, or was insufficiently reliable to perform in a cluster of five and launch on time in tight lunar launch windows, or could not have been manufactured in the quantities required, there would be no lunar landing. If the schedule of the F-1 slipped, the Apollo project would slip day-for-day along with its prime mover.

This book recounts the history, rationale, design, development, testing, refinement, transition to serial production, integration into test articles and flight hardware, and service history of this magnificent machine. Sadly, at this remove, some of the key individuals involved in this project are no longer with us, but the author tracked down those who remain and discovered interviews done earlier by other researchers with the departed, and he stands back and lets them speak, in lengthy quotations, not just about the engineering and management challenges they faced and how they were resolved, but what it felt like to be there, then. You get the palpable sense from these accounts that despite the tension, schedule and budget pressure, long hours, and frustration as problem after problem had to be diagnosed and resolved, these people were having the time of their lives, and that they knew it at the time and cherish it even at a half century's remove. The author has collected more than a hundred contemporary photographs, many in colour, which complement the text.

A total of sixty-five F-1 engines powered 13 Saturn V flight vehicles. They performed with 100% reliability.

Posted at January 16, 2012 21:01