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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 — 25 Comments

  1. Hi Jonathan,

    I’ve just read Rocket Ranch, I like it very much!

    I’ve found 3 typos:
    1. Page 99, Fig. 5.4 – Apollo 13 was stacked in High Bay 2, but the text marked with one asterix says High Bay 3
    2. Page 147, “This red pushbutton can be seen in Fig. 2.15” – it should be Fig. 6.15
    3. Page 265, Fig. 9.11 – date of SA-1 should be October

    Countdown is on order, it will be a perfect reading for Xmas break :-)

    Zoltan, Hungary

      • Hi Jonathan,

        I’ve finished reading the Countdown, I could not put it down :-)

        There are some minor typos:
        1. Page 126, Fig. 5.1 – Date is January 9 however 5 rows below January 12 is written.
        2. Page 132, Week of January 27 – “Mylar tub blankets were installed” Did you mean tub or tube?
        3. Page 183, Fig. 5.4 – Apollo 13 was stacked in High Bay 2, but the text marked with one asterix says High Bay 3.

        Thank you for your excellent books. During reading sometimes I felt I was onsite at KSC.

        Zoltan from Hungary

  2. I cannot get my question about the F-1 turbopump answered by any of the books I currently have. I’m developing a course for retired adults and I want to “get it right.” I don’t want to guess.

    Both Stages to Saturn (page 111, and 116-119) and The Saturn V F-1 Engine (pages 86-96, and 98-100) both seem to imply that the MK 10 F-1 Turbopump goes from full stop to full speed operation all within the “ignition sequence start” timeframe of T-8.9 seconds to just prior to liftoff. This seems incredible to me—almost beyond belief.

    In contrast, the book Apollo: The Race to the Moon, by Murray and Cox, states on page 244 of the cloth edition, “At T-30 seconds, the 55,000 horsepower turbines that drove the S-IC’s 5 engines powered up. At T-8.9 seconds, an electrical signal was sent to the igniters…” and then proceeds to describe, in more or less plain English, the ignition sequence described in detail in Stages to Saturn on page 111 of the U.S. government version of that publication.

    I just don’t get it. Are Murray and Cox correct, and does the turbopump really begin operating at T-30 seconds, long before “ignition sequence start?” It would almost seem to me (as a layman trying to understand this pump) that this would have to be so.

    But if this is true, what drives the turbopump beginning at T-30 seconds? Was it the gas generator? The Gas Generator (according to page 111 of Stages to Saturn) is “lit off” at T-8.9 seconds when two of the four F-1 igniters ignite the propellants inside the gas generator. If this is literally true—that the Gas Generator for the Turbopump is not “lit off” until the 2 igniters in the Gas generator begin to burn at T-8.9—then what drives the turbopump beginning at T-30 seconds?

    Or were Murray and Cox wrong about the Turbopump starting at T-30?

    I would really appreciate any definitive help that you or anyone else (like Jonathan Ward) can provide, along with citations re: where you got the answer from!


    Douglas Horne
    Middleburg Heights, Ohio

    • From Jonathan Ward:
      Thanks for your question! I went back and checked the Apollo 11 Launch Vehicle Countdown Procedure, V-20060, Volume 2. There is no reference to the turbopumps being powered up starting at T-30 seconds, or at least there is nothing in the procedure showing that anyone in the Firing Room was monitoring something like that. The NASA S-IC/Vehicle Terminal Countdown Sequence Interlocks diagram also fails to note anything about the turbopumps starting at T-30 seconds.

      Back to the Launch Vehicle Countdown Procedure: As you noted, the ignition sequence started at T-8.9 seconds. Two igniters were started at T-8.8 and T-8.7 seconds. The links were burned at T-6.7 seconds, which sent an “ENGINE ARMED” indication to the DEE monitoring computer. Engines 105, 101, 103, 104, and 102 were started at T-6.46, T-6.13, T-6.07, T-6.00, and T-5.87 seconds respectively. At T-4.7 seconds the S-IC secondary pre-pressurization valve was open. The S-IC fuel auxiliary pre-pressurization valve was open at T-2.75 seconds. At T-1.92 seconds, the “ALL ENGINES RUNNING” indication came on to show that all engines were up to speed. Final thrust checks came at T-0.05 seconds, with launch commit at T-0.0.

      So it appears to me that the engines went from a cold start to full thrust in just a few seconds.

    • I am certainly not an expert, but it is my understanding that before ignition actually occurs, the LOX valve is opened, and liquid oxygen under tank pressure flows through the LOX part of the turbopump and starts it slowly turning before ignition of the gas generator (known as a “tank-head start”). This causes there to be less of a shock in starting the turbopump, and makes it slightly more of a staged affair. Hope this helps…

    • I forgot to mention one thing: the book you want to get your hands on is “NASA Saturn V 1967-1973 (Apollo 4 to Apollo 17 & Skylab) (Owners’ Workshop Manual)” by David Woods. You can get it at Amazon.com for around 30 dollars, and it contains just about the most detail you will find about both starting and shutting down the F-1, as well as practically every other detail of the Saturn V.

    • After some digging, I believe I can now provide an answer to Mr Horne’s core question. According to the Rocketdyne “F-1 Engine Familiarization and Training Manual”, the turbopump for the F-1 builds up to it’s rated speed of 5492 RPM not in 8.9 seconds, but in 5.2 seconds. Time from turbopump cutoff to zero RPM is 3.5 seconds. The initial oxidizer dump I mentioned in my first reply brought the turbine up to 700-1000 RPM just before the gas generator was ignited. One reason some may think the turbopump took longer to spin up and provide the necessary fuel/oxidizer to the engine is that most videos of an S1C startup are presented in extreme slow motion. A real-time film of an S1C test will show the engine start-up is quite a bit quicker than one might at first think.

  3. Hi, I am old enough to remember the Apollo Era, and have read lots of books about it. However I have one nagging question that I hope someone can help with:
    The astronauts reports that they are thrown forward at staging, I even think I remember reading that some saw a fireball go past the windows in forward direction at staging. How is this possible? The astronauts must encounter negative g to be thrown forward in their seats, and neither stopping the old stage’s engines, nor ullage engines on the new stage should give negative g. So my question is, what is it that causes this effect? Are there retro rockets in use while staging?

    Hope someone can answer, this has been nagging me forever :)

    • Thanks for your wonderful question! You got me thinking, too. My best guess is that the astronauts probably felt like they were being thrown forward. When the first stage engines shut down, the astronauts went from four G to zero G almost instantaneously – but you’re right, not negative G. When your seat suddenly stops pushing against you with a force four times your weight, you’re going to feel like you’re flying forward even if you aren’t. Your natural instinct would be to throw your hands up in front of your face to protect yourself from the control panel that’s only a couple feet in front of you. As for the report on Apollo 10 of the flames coming up to the window at staging, I would bet that it was the retrorockets firing on the S-IC. There were eight retrorockets, two in the top of each of the conical engine cowlings to which the fins were attached. At staging, the ends of those cowlings were blown off explosively and then the retros fired, facing forward. Since the rocket was essentially in vacuum at that point, the exhaust plumes could easily have reached the top of the stack and would have been visible to the astronauts.

      Jonathan Ward

      • Ah yes, retrorockets on the previous stage could surely account for the fireball.

        I will try to find and reread what the astronauts wrote about staging to see if it could match going from 4g to 0g. I thought of this as a possibility but discarded it, but will recheck what they said.


        • And I am back with more info :)
          (From https://history.nasa.gov/afj/ap10fj/as10-day1-pt1.html)
          Tom Stafford from the 1969 Technical Debrief – mentioned that they thought they would encounter a single pulse of negative G at staging as the S-IC cutoff and the crew would be thrown forward in their straps, before the S-II ignited and recommenced the acceleration. However they actually encountered was a form of pogo which continued for 4 cycles, during which they were “slammed forward, back, forward, back, forward and back” (direct quotation) and the instrument panel appeared blurred during this time.

          This certainly does not sound like just going from 4g to 0g.
          I have a new theory: Something was compressed while at 4g, and it expanded back at 0 g resulting in slushing of the fuel in S-II. This could give rise to the pogo effect at staging. Its interested that they expected negative g. I still wonder where that expectation came from when they did not expect the pogo.

          • Rusty Schweickhart told me that the “being flung forward” effect was due to the whole metal body of the rocket stack being compressed due the thrust, and when released from thrust it sprung back out to its full length. That impart a forward impulse to all the contents, including the astronauts.
            Ken MacTaggart

  4. 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

  5. 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.

  6. 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.

  7. 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.


  8. 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”

  9. 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.

  10. 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

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