Home Page

This site contains information on Apollo-Saturn Launch Processing at Kennedy Space Center (KSC), focusing primarily on its people. The site has already provided information for two new books on the subject by Jonathan Ward. “Rocket Ranch: The Nuts and Bolts of the Apollo Moon Program at Kennedy Space Center” and “Countdown to a Moon Launch: Preparing Apollo for Its Historic Journey” were published by Springer-Praxis Books to rave reviews in July 2015. To order signed copies of both books, click here.

Please visit our sister site at http://www.apollolaunchcontrol.com for more information on Apollo-Saturn support at KSC, and check back here often as this site continues to evolve and grow!


You can help us identify people in some of the many photographs of the period by clicking on this link:  The People of KSC.  The photos that follow are various NASA and contractor teams from Apollo-Saturn, as well as a few earlier missions. We are trying to identify as many of the people in the photos as possible.

If you have other photos of yourself or your team from Apollo-Saturn days, please feel free to email them to us at info@apollo-saturn.com. With your permission, we would be glad to include them on the website. Stories and comments about individuals or your team are also welcome. 

Thank you for your help and input!


Home Page — 12 Comments

  1. The S1-C thrust structure, the lowermost component of the 1st stage, served two purposes. (1) It was the base of the launch vehicle and it supported the entire deadweight of the LV and Apollo spacecraft at four points at the lower thrust ring as it rested on the Hold down arm base. The hold down arm proper was the ‘clamping’ component which gripped into a large slotted verticle column built into the skin of the TS. (2) The TS, after ignition, absorbed the upward thrust at five points (4 at circumference, 1 in center) and sheared it into a uniform loading towards the upper thrust ring. There’s more. write for details pics etc. MF

  2. I have read ROCKET RANCH and currently reading COUNTDOWN and have become a fan of this website. Great to read from a workers view. I have a question. Is audio of the interviews available or maybe download in the future. It would be great to sit back and listen to these stories. I did find the interviews to Stages To Saturn and they are great too. Great site.

  3. As a structural engineer, I too had a keen interest in knowing how the engine trust was transferred onto the body of the Saturn V, and I can share some of what I’ve found. There is a ball and socket (a concave impression in a plate at the top of the thrust chamber that takes all of the thrust from the engine. The ball of each engine is attached to and transfers load to a “thrust transfer structure”. This structure is made of two plate girder type I-beams that cross each other at 90 degrees to form an ‘X’ shaped cruciform. These beams are as long as the diameter of the lower skirt, so that each beam is attached to the skirt at each end, for a total of 4 connections. Put simply, the X shaped cruciform chris-crossed the bottom of the tank. Four engines were attached to each of the 4 legs of the cross, and one engine was attached at the center of the cross.

    The ball and socket connection transferred the thrust of the engine to the thrust structure, yet permitted the engine to pivot about the center of the ball. There were several tube struts attached to the perimeter of the thrust chamber that were connected to hydraulic actuator cylinders, which in turn were attached to the thrust structure. Fuel (kerosene) was pumped into the actuators to laterally push or pull the engine in order to pivot it and steer the rocket. Hope this helps.

  4. Dear Mr. Ward: I have just begun to read your book, “Rocket Ranch” in hopes of discovering how the Saturn V was mounted in its upright position. I am especially interested in understanding how and where exactly its gross weight was supported. Most images show simplistically that the rocket sits on its engines. This cannot be correct given the enormous weight of the stack. There must have been a system of support beams/rings/levers that allowed the stack to sit on some form of concrete structure with the engines themselves free to swivel. The problem of stability of the total stack is also of interest. Whether it be the Saturn series of rockets or the Space Shuttle, the problem of supporting the massive weight of the structure and keeping it upright in the shifting winds and changes in center of gravity as fuel is loaded has not been adequately explained. Do you have any information or resources I can look up on this complex system? Perhaps I will find it on further reading of this book or your companion volume entitled “Countdown?”

    • Hi James,
      Thanks for your question!

      You are correct – the Saturn V did not sit on its engines. The engines protruded down into the square opening in the mobile launcher and were free to gimbal. The weight of the Saturn V rested on heat shield and thrust structure at the base of the S-IC stage. The vehicle was supported entirely by the four holddown arms on the launcher deck. One of the holddown arms is visible in the center of the accompanying photo (which my dad took in August 1969!). You can see that the engine cowlings are ‘floating’ above the yellow-painted engine servicing platform. Those arms held the vehicle in place, although there was also a “viscous dampening system” bar that swung down from the top of the umbilical tower and connected to the base of the launch escape system on the Apollo spacecraft. That provided additional support to the vehicle to keep it from swaying during rollout and while at the pad.

      Each holddown arm was about 6 by 12 feet at the base and weighed 37,000 pounds. The holddown arms were supported by a network of beams and girders inside the mobile launcher. Together, the arms were preloaded with about 1.2 million pounds of pressure – just a little more than the difference between the thrust of the S-IC stage and the weight of the fully-fueled Saturn V. That is, the combined forces of gravity and the pressure exerted by the holddown arms held the Saturn V down while the engines built up thrust. At the Launch Commit signal, all four holddown arms released simultaneously. The process is explained in more detail in “Countdown to a Moon Launch.”

      Incidentally, there were 8 holddown arms for the Saturn IB rocket. The weight of the vehicle was borne by the base of the fins, where they attached to the S-IB stage. The Space Shuttle stack was attached to the mobile launch platform near the base of the solid rocket boosters. Massive bolts held the Shuttle to the platform, and frangible nuts were pyrotechnically severed when the SRBs ignited.

      9.20 S-IC holddown arm and tail service masts

      Jonathan Ward

      • We got a further question from Jim Mathewson:

        Thank you for your detailed and lucid explanation of the support/hold-down system prior to launch of the Saturn V.

        One aspect of my original question remains unanswered. This relates to how a rocket engine is designed such that the thrust it produces is mechanically transferred to the vehicle. This sounds simple enough, and looking at diagrams of rocket motors, one sees the engine positioned at the base of the rocket with lots of pipes and tubes between the rocket base and the thrust chamber. It is assumed that the forces at lift-off are contained and transferred to the vehicle, but how this is accomplished is not clear.

        What these diagrams do not show/explain is how the complex tangle of pipes and other structures above the thrust nozzle is constructed such that the thrust created is transferred via and through them to the rocket body. The hot gases are escaping from the thrust chamber after having passed through the De Laval nozzle. Those forces impinge on the thrust chamber and nozzle such that they push the vehicle forward (upward). To contain those forces requires significant structural engineering, structures that are not obvious when one looks at available rocket motor diagrams.

        The unexplained “x” is the construction of the bell, nozzle, and intervening parts such that the forces are contained and transferred to the stack. I assume there must be steel arms/members that connect the bell and nozzle in some way to the base of the vehicle and which still allow the outside engines to gimbal. Surely there must have been some form of hydraulic pressure control as well to dampen the initial forces. All anyone who is not a trained engineer can see in available images is an ellipsoidal engine bell with a narrow neck attached to lots of plumbing which in turn attach in some manner to the lower end of the rocket. In the case of the Saturn V, 4.8 million pounds of thrust were transferred to the base of the stack at liftoff and during climb-out.

        Can you please provide a schematic or other explanation that will provide some visual image of how those forces were accommodated such that the engines did not tear themselves apart? The narrow neck of the engine bowl must obligatorily concentrate all of that thrust in a very small space as it impinges on the vehicle. The support structure must be massive to contain it, yet to the untrained eye it looks very delicate. By way of contrast, the hold down arms each weighed 37,000 pounds and were constructed of thick, heavy steel beams. How they did their job is more or less obvious. The interface between the engine bell and plumbing and the base of the rocket does not look to contain such massive girders. And yet the forces contained were in the millions of pounds! To any rocket engineer this question no doubt may seem mundane. But to me it is a complete mystery.

        Jim Mathewson

        • Jonathan replied:

          Hi James,
          My apologies for not discerning the question you were asking.

          I agree that there are mammoth forces to contend with in designing the Saturn V! However, I’m not an engineer and I don’t really have sufficient knowledge about the design and fabrication of the Saturn V to be able to answer your question in satisfactory detail.

          I will point you to a couple of online resources that may at least partially answer your questions.
          The first is “Stages to Saturn,” which discusses the design and evolution of the Saturn stages and launch vehicles. It’s available at http://history.nasa.gov/SP-4206/contents.htm

          The second is the various Flight Manuals which Marshall Space Flight Center prepared for the Apollo crews. The story goes that these were first prepared at the request of Frank Borman. At a meeting with von Braun, Borman was asked if there was anything he needed to know about the Saturn V that his crew would be the first to ride. He said, “Yeah, where’s the flight manual?” Von Braun did not know what he was talking about, and he had someone from his team interview Borman about what needed to go into such a manual. The result is shown at http://history.nasa.gov/ap08fj/pdf/sa503-flightmanual.pdf
          There was one such manual prepared for every subsequent Apollo mission. The content is pretty much the same for the Saturn V missions, with a few variations as the Saturn V’s performance was uprated. There’s also one manual that covers the Saturn IB’s for the Skylab missions.

          I hope this is useful.


  5. Most diagrams of the physical components of the Launch Processing System show an inordinately large rectangle at the center of the drawing, with all other components either directly or indirectly connected to it. That rectangle represents the common data buffer, which Thomas Walton called the “cornerstone of the system”

    • Most diagrams of the physical components of the Launch Processing System show an inordinately large rectangle at the center of the drawing, with all other components either directly or indirectly connected to it. That rectangle represents the common data buffer, which Thomas Walton called the “cornerstone of the system”

  6. Not mentioned in either book, because I forgot to tell you about the Orange Room in Firing Room 4 pertaining to the Boeing TIE LC-39 site activation scheduling activities. There was a very important effort accomplished by my immediate supervisor Don Boyce. He was in charge of the Orange Room in Firing Room 4. He held daily coordination scheduling meetings between Site Activation Contractors to monitor accomplishments and to identify and resolve conflicts and problem areas. After the daily meetings the Boeing TIE schedulers were give marching orders to go take a first hand look at all facility contractor progress and access problems. Therefore Don Boyce deserves credit for his efforts in helping the LC-39 Site Activation happen in time to support Launch Operations in our effort to land a man on the moon.

  7. Hi–my Dad was Canaveral District engineer around 1965-69. He wrote a little book about construction of one of the launch pads. Not sure if you plan to include work of US Army corps of engineers at space center in your work. Also I met Jane and Gwen at Penland! MJL

Leave a Reply

Your email address will not be published. Required fields are marked *