How To Start The Massive F-1 Rocket Engine – Explaining “Ignition Sequence Start”

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Seconds before the launch of a Saturn V we hear the launch commentator calling out ‘Ignition Sequence Start’. The ignition sequence is a complicated series of steps which spin the engine up to speed and light the combustion chamber so that the rocket lifts off rather than explodes.

  1. François Dion

    I’m giving her all she’s got captain!!!!

  2. dr.rockzo

    Huh I always thought they just turned the switch to run and pulled the cord a few times.
    Great video Scott.

  3. give me pizza or give me death

    the complexity, size, fury and success of these engines has always astounded me. The people who engineered these things are phenomenal.

  4. Timothy Pirnat

    Continued great content Scott! I agree with the other poster who are requesting a pogo vid. How exactly does a helium tank prevent this phenomenon?

  5. Kyle Brown

    can’t wait for SLS and BFR launches, hope they’re even more spectacular

  6. StonyRC

    Thanks Scott, that was succinct, clear and very well presented. Answered all of my questions about the F1 startup.

  7. FiiZzioN

    This has to be one of my favorite videos you’ve produced… Simply stunning!

  8. Andrew Naylor

    How do the hold down anchors work ? now the engines are lit and it needs to go
    thanks Andy

  9. Nerdzy

    Fascinating! I love to learn about all of these fine details. Next you gotta explain the second stage ignition.

  10. Spenser Hawk

    Starting is easy. Have the key fob in your pocket, then press the start button. All done.

  11. Jason Grime

    These technical explanation videos are just great. Keep up the good work Scott.

  12. Ali Gallaton

    Well, this detracts from the belief that someone just presses Z and Spacebar and then fire.

  13. brian whittle

    I visited Cape Canaveral in 96 they have/had one of the Saturn V rockets, they are rather large.

  14. Frank B

    I was a kid during Apollo and Gemini and it was a huge thrill to see a rocket launch on black and white TV.
    Nice video

  15. Pyro Doll

    Brilliant as always Scott, thanks for doing what you do xx

  16. Adam Crossley

    So Scott, what your saying is – push that button there. ;)
    Seriously, thanks for this I watched it twice! :)

  17. Steve Hand

    Very interesting , love the Apollo and everything with it. Thanks again and keep them coming .

  18. hoorayimhelping

    Great editing Scott! Loved that you explained everything, then showed a couple of shots of the startup sequence. I was totally able to follow along with the whole process you just explained. Awesome!

  19. Gustav Gnöttgen

    And the award for the most epic thumbnail goes to – Scott Manley and his awesome work!

  20. andrew nelson

    I’m torn on which intro I like the best. I think Scott holding the rocket model is my current favorite with the beat boxing ;o)

  21. VikramJeet Das

    Things KSP doesn’t teach:
    1. Engine gimbaling
    2. Pogo suppression
    We need a video about these, Scott! Thanks. :) :)

  22. Alex Trilby

    You’re the manliest Scott I know

  23. Eddie Murphy

    That is brilliant, Scott, absolutely brilliant. Great video

  24. HSTDriver

    Nice explanation and video. Thanks for posting 👍

  25. Mather Focker

    Thank you. I now have all of the skill necessary to proceed. Now I shall begin my own space program.

  26. LaryGolade

    Yeah ! Scott Manley mechanical engineer and CuriousMarc flight engineer, let’s go to the Moon !!!

  27. Backside of Blue

    Absolutely amazing stuff. I love the F1 engine even more than before. Keep up the great work!

  28. Radio Active

    And THAT folks, is why they call it ‘rocket science’. The concept is simple to understand: chemicals combine and burn and you get thrust, but dam if the actual engineering isn’t hard as hell. Glad Scott Manley gave a rather simple diagram for non-rocket scientists like myself to understand. Keep up the good work, Scott Manley.

  29. Alan Beck

    I’m not a rocket scientist, but I have had the honour of jumping around the engines in the display area in Florida. I get excited by this YouTube content.

  30. WildPhotoShooter

    And some crazy nutters think NASA does all this to hide a flat earth (and God) from them !!!!!! Hahahaha! Lunatics.

  31. John Murphy

    You failed to mention the very first valve that opens which allows the constant flow of English accent ;) (Thanks for the vid)

  32. overdoneone

    WoW! I was always taught to: Place on ground, light fuse and run away…..use under adult supervision only….

  33. lietkynes81

    Wonderful video!
    Now THAT’s the stuff rocket enthusiasts thrive upon :)
    Thanks Scott!!

  34. Grumpy G

    I’m so glad you mentioned the “cold helium” contribution, that’s always been a source of angst for me. Thank you for sharing.

  35. Gianni Barberi

    Simply wonderful, I was 7 50 yrs ago and always wanted to know more about the missions

  36. William Dilley

    The accumulator helped reduce vibration, like a shock absorber on a car.

  37. Dan Lewis

    Remarkable. Thanks for sharing.

  38. carbo73

    Amazing and very informative. Many thanks Scott. Keep up the good work!

  39. Harry Barrow

    PS I am old enough to remember Sputniks (saw them both from our back garden), and everything that followed. 👨🏼‍🦳

  40. Erik Broeders

    Sooo… if I mount this engine on my motorbike, I will be basically… flat, won’t I.

  41. nitestryker7

    Love the minecraft fires for demonstration.

  42. oak

    I was privileged to be at an F-1 firing (two miles away) at Huntsville in 1963 impressive beyond belief…however the Glycol fill is new to me….

  43. Karl West

    That’s a great explanation of how these engines are switched on, but how are they switched off? Do they just maybe close some valves to stop propellant and oxidizer from getting into the combustion chamber? Not an engineer here asking…


    Fantastically produced, Scott!
    I used to be in commercial HVAC.
    Big thermoses w/a few overbuilt Weber grills bolted on.
    I got this, thx. 👍😆🚀

  45. Kujeful

    Wonderful breakdown of the startup sequence, thank you! I love the punchline at the end.

  46. Curt Nicholson

    Very interesting, and most if not all of this was developed by engineers and scientists not using computers but slide rulers and there brains. Amazing simply amazing!

  47. mycroft16

    The slow motion footage of the exaust gasses flowing out of those engines is always fascinating. The raw power in those engines is just staggering. Also… when your coolant is at 1,000 F. lol

  48. jtech0

    I always thought that the rockets were started by those things that threw all the sparks around the bottom of the engine.

  49. bob s

    Light blue touch paper, stand well back…

  50. gedstrom

    And here I thought that a guy with a match lit a fuse at the base of the rocket and then ran for his life! :-)

  51. Xavier

    hi! Idea for a future video : what is the internal sturcture of a rocket, the structure that makes it stay as it is, and which preserves its integrity when the mass opposes the thrust? Which part of the engine supports all that mass?

  52. mrgeraldbrent

    The fuel pump. Just the fuel pump per engine. Takes 55,000 brake horsepower to run.

  53. j4d3 goat

    “How To Start The Massive F-1 Rocket Engine…”
    “Darn it, bro, I left the keys at my g/f’s place in Houston……… “

  54. Steve Fick

    Hat’s off to the men and women who thought up this stuff. Amazing engineering! And that’s just the engines!

  55. 104thDIVTimberwolf

    This is your best since I found your channel, Scott, and that says one hell of a lot.

  56. Tony Brown

    It’s bloody hard to comprehend something consuming 2 tons of fuel per second.

  57. Richard Bull

    I’ve known for a long time a rocket engine is far more complex than just a chamber that burns fuel and oxidiser but this blew my mind as to the true engineering magic that goes into them. Beautifully explained Mr Manley! Thanks.

  58. mwolfod

    Brilliant explanation of a stunning triumph of engineering.

  59. Steven Moody

    Much easier than figuring out the remote for the tv. 🤣

  60. Sean Baskett

    It’s always fun to listen to Jack King say “Ignition sequence staaht!”

  61. telescopereplicator

    Scott… do realize you are giving away very sensitive information…??
    Now everybody can go build their own Saturn V rocket…………;-)
    Great video.
    Increased my respect and admiration for these guys even more.

  62. John Mehaffey

    I remember werner van braun describing the Saturn 5 and he said it was a simple rocket design, yep simple for you mr van Braun but slightly more complicated for me I’m afraid

  63. Al Fo

    On holiday. Enjoying a dram. Just learned how a Saturn V engine works. Surreal…. And wonderfully more enjoyable than watching TV! Scott, you’re doing a grand job. Thanks 👍

  64. Wojciech Kasprzak

    That was tightly packed 8 minutes 😊. Great work!

  65. Ted Garrison

    Petition to bring back the X-Wing intro back!

  66. 00UncommonSense00

    There’s a video on why we can’t make these engines today. I think it’s made my Curious Droid. You would think that with our level of technology today we could not only make them again, but make them better. Not even close. Much of the work was done by engineers who were making changes on the fly. The main design would be considered version 1.0. The engines on the actual Apollo were using version 4.5 (a rough analogy) all those changes/updates/mods were kept in each engineers notebooks, which we don’t have. And a lot of it was in their heads, which we don’t have (lol) And much of the machine tooling, like the massive presses, punches and brakes are gone. It’s a fascinating video to watch. I don’t mean to talk about another’s video, but I think it dovetails nicely with this video. Well made and researched. Liked and subbed.

  67. Renate Bauer

    Ok… This IS rocket science :D

  68. tubeist- dan

    You can appreciate why Bob Truax went with dirt-simple pressure-feed with the Sea Dragon concept.

  69. ShinVega

    Note: The turbopumps that delivered the kerosene and LOX were 75,000 horsepower….

  70. Bram Moerman

    So now we know whyits called “Rocket Science”. . . It’s not just about orbital mechanics. . . 😀

  71. catfish552

    That’s very helpful, I can never get mine to start right!

  72. David Fountain

    People should also remember that there were four launches of Apollo in 1969. Apollo 9 in earth orbit, testing the Lunar lander for the first time, Apollo 10 which was a full up dress rehearsal of the lunar landing, Apollo 11 and Apollo 12, both of which landed on the moon. So it’s a 50th anniversary for all those crews!

  73. adbell3364

    Excellent! Simply superb! Eight minutes and change, and I learned more about the Saturn V launch than I have in the last 50 years. Thank you, Scott!

  74. Bosron BGman

    Happy 50th anniversary!!! Can you talk us how the communications work all around space. The antennas, microphones, dishes, time of transmission from the planets or particular missions and so on?

  75. Jeffrey Lindsey

    Interesting and informative Video. Thanks Scott

  76. Alex Altair

    This is the perfect amount of detail for me. I would love to see a similar video for other engines!

  77. Ze Great Pumpkinani

    2:45 accurate diagram of how Minecraft Galacticraft rockets work

  78. AlabamaPanther 1776

    So on the igniter, there is a little “aspirin” tablet that then lights a solid fuel components that looks kinda like a dynamite stick. After numerous successful test, they suddenly started having catastrophic engine failures. They sent the engines over to the vibration and acoustics labs at Marshall in Huntsville. After running numerous test, they couldn’t figure out what was wrong or different, until the head shock and vibe engineer (one of the best in the world) noticed a previous good vibration test set that didn’t have such a “shocky” graph pattern so early in ignition. Comparing the two test, he realized whatever was going wrong was happening during the igniter start up. He went to the purchasing guy and asked “did you change where you bought these little “aspirin” tablets?” the purchasing guy said “yes, a salesman came in about two months ago and showed these burn much hotter and fit the same spec.” After switching back to the old “tablets”, the engines went through another successful test…apparently, the hotter igniter tablets were breaking the solid fuel components apart and causing uneven burning that then causes basically a mini-explosion because you started mixing the remaining solid fuel and LOX. So that’s how a 80 cent item almost shut down the Apollo fights.

  79. TMA1

    Just re-reading Chaikin’s ‘A Man on the Moon’:
    Charles Lindbergh the day before the launch of Apollo 8, asked how much fuel the Saturn V would consume on ascent – 20 tons per second they said.
    “In the first second of your flight tomorrow, you’ll burn ten times more fuel than I did from New York to Paris”.

  80. Roelf Pringle

    Great, but now I need a video on the POGO suppression

  81. jaime barr

    So … my uncle lied about the hamster that was running the turbo pump? I knew it!

  82. Nick Hassett

    I’m really curious – what structures are bearing the weight of the Saturn V whilst it’s on the launch pad? Ahyone?

  83. Wes Anderson

    Fook’n Hell…I thought it was some dude lighting a fuse, & then, running like fook’n hell😃

  84. Alex Hatfield

    When Jack King NASA PAO announced “ignition sequence start”, his voice charged with adrenalin, my 8 yr old imagination lit up like those F1’s, my heart raced like the clappers, and my mouth dropped open. What a ride Apollo. There’s never been a Global adventure quite like it since…

  85. Coastfog

    That’s why I love Astronomy and space engineering – it might seem very complicated at first, but when you keep digging deeper and deeper, you’ll soon realize that it’s even more ´complicated.

  86. mlnlme1

    How to turn on a rocket engine. Press Z, then Spacebar

  87. David Cowie

    “Thirty seconds and counting. Astronauts report it feels good. T-25 seconds. Twenty seconds and counting. T-15 seconds, guidance is internal. 12, 11, 10, 9 … ignition sequence start … 6, 5, 4, 3, 2, 1, 0 … All engines running. Liftoff! We have a liftoff … 32 minutes past the hour, liftoff on Apollo 11. Tower clear. ”
    — from

  88. William J.

    Still easier than getting my wife in the mood. 😂

  89. likhith km

    Need a video completely dedicated to Pogo suppression systems!!! Great video tho!!🤩

  90. flippynl

    can you explain how the gimbal works? putting 700 tons on a strut and making it move at the same time seems quite the engneering challenge

  91. gmpsandw

    Even mow 50 years later it still gives me goose bumps to see that thing go up. Amazing.

  92. Tony Wharton

    2 tonnes of fuel per second?
    And I thought my kia was bad.

  93. 5Andysalive

    Saturn V launches never get old to watch.

  94. Theophrastus Bombastus

    2:35 Such schematics really makes us appreciate the countless redstone engineers that worked tirelessly to create such a marvel

  95. Michael Johnston

    “Casual combustion “. As a volunteer firefighter, I’m stealing that for training purposes.
    “No that’s not a backdraft or a flashover. It’s just some casual combustion. “

  96. Brian Clark

    Oh man, I should have watched the video on how to turn off the F-1 first. CAN ANYONE HELP?! IT’S REALLY LOUD!!!

  97. mr man

    alternatively: just press spacebar. then watch in awe as flames & smoke billow from one end of your rocket, and parachutes deploy from the other!

  98. Adam Wishneusky

    omg my F-1s have been sitting around idle because I didn’t know how to start them. Thanks! 😜 — srsly tho, thanks for another awesome video!

  99. Daniel A

    I love your ultra scientific Minecraft fire graphics!

  100. Wojciech Dubrownik

    Okay Scott, you can’t just casually mention the pogo suppression system without at least roughly explaining what it ts.
    I’d love a video (or at least a segment of a video) explaining what it is and how it works 😋

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