Why Rocket Exhausts Look The Way They Do

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Why does the exhaust from the Space shuttle boosters & engines look completely different? There’s a huge variety in the appearance of rocket exhausts because different fuels, different technologies and different environments make them behave in a different manner.

  1. Stephen Ritger

    Great video! And, yes, who doesn’t love the Saturn V…best rocket ever!

  2. zimmy1958

    THANKS loved all the info you gave here

  3. Redshift

    Absolutely fascinating…thank you Scott.

  4. 19ghost73

    Thanks for this detailed info that is commonly not found. It answered some questions that I had for many many years! ATB, Gereon

  5. Dav 4321

    When I was 10 I noticed that plume from the exhaust, as the rocket got higher, I’m 57, thought it was camera angle or something.. Thanks

  6. RocKiteman _ 2001

    Scott, I bet you were *EXHAUSTED* after making this video…😊

  7. Galileo Gaming

    Thanks for making this, always been curious about that myself.

  8. Lawrence D’Oliveiro

    4:12 Because the gas is at low pressure, so it shows its Fraunhofer lines (absorption/emission spectra). At higher pressure, these disappear.

  9. Dobromir Manchev

    Thank you Scott for making this kind of videos, for us plebs who don’t have the courage to learn proper rocket science but are knowledge hungry!

  10. willy p00

    woof, love science and engineering explained well.

  11. Hans

    More of that. Please.
    Also should have probably mentioned the pad protection water creating those massive clouds at launch

  12. Clinton Gryke

    Doh! Should have watched a little more before asking!

  13. Jeremy McMahan

    I’ve loved all of your videos, but this one stands out! Thanks for the great research and very clear way you teach.

  14. James

    Bloody good video Scott. Loved it! 😃

  15. Sulev-Madis Silber

    hah, i never realized that shuttle engines are ALSO on but not visible due exhaust being clear… not to mention it took me many years to realize roman numerals being used to number the saturn rockets (… and things like osx)

  16. Anton Lejon

    “which is a very long word, but…” – you’re the best!

  17. Andrew Parker

    Scott Manley, you never fail to amaze me

  18. Peter Dawes

    I will never look at the exhaust trail of a rocket engine quite the same ever again. Thanks Mr. Manley, that was very interesting.

  19. richb313

    All I can say is thanks for the explanation. I really enjoyed learning even a little bit about this.

  20. Gianluca Bovolenta

    I usually don’t comment but I need to tell you mr. Manley that this is one of your best videos to date.
    I watched almost every video of you and I am eager to watch them as soon as they come out but this time you really reached the top of quality, montage, information and amazing visuals.
    I saved this video to my favourites and I’ll watch it again more than once, pretty sure of this.
    Keep up the good job, you are truly an inspiration 👍

  21. Shoorit

    Love how the nozzle flexes in slow motion on the RS25’s during ignition, amazing pieces of kit.

  22. Nathanael Vetters

    I do love that upper-atmosphere Falcon 9 plume.

  23. Stephen Irwin

    What a great explanation of the various rocket plumes – so clear and concise! I really enjoy your segments.

  24. jnew

    Wow I just found your channel… amazing!!!

  25. vk3tkq

    I like the Saturn five.
    You did say who doesn’t like the Saturn five…..
    I also like your videos Scott keep up the good work.

  26. Rebeca Mugwort

    One of your most compact and concise videos yet!
    Very informative too. :)

  27. Adam Harvey

    Scott, I was under the impression that the Raptor prototype shown used spark ignition rather than pyrophorics. The best explanation I’ve seen for that particular green flash is chromatic aberration due to overexposure.
    Great video overall, though!

  28. assassinlexx

    Simply put thank you for great explanation of rocket motors.

  29. mikldude

    Always cool looking at rocket science and rockets operating ….. the slo mo is amazing .
    thanks for posting .

  30. Will K

    Thanks Scott. Could you do a series on Chinese Long March rockets? and also launch systems from India, Japan. Thanks.

  31. newsgetsold

    Thank you Scott for helping us appreciate the art, poetry, flowers and diamonds🌼🌷💎💍… of sooty exhaust plumes and burnt byproducts. 😁

  32. Bo

    now i understand you remind us to -drive- fly safe. so much 🔥

  33. Conrad Myers

    Awesome video. Always wondered about that on the Saturn V. Many thanks

  34. Joseph Groves

    Welcome to Aerodynamics2, Incomprehensible Flow through Converging-Diverging Duct

  35. Kenneth Morton

    Excellent Video. I really apprceciate the work thats gone into this. Your right BTW, the F1 engine is definately the most awsome thing to leave a launch pad.

  36. almond potato

    First time I saw shock diamonds were in SpaceX’s test of their Raptor engines.

  37. James Hodges

    These clips are amazing

  38. theoryaction

    Scott Manley, you’re one of my favorite scientists. Even though I don’t always understand everything you say, I always like the way you say it. Fly safe!

  39. Deep_Dive

    Why did the British RP1 Hydrogen Peroxide rockets produce such a clear exhaust?

  40. ChrisBrengel

    Great job finding the photos
    Great video-thanks

  41. Don Cely

    What Atomjonesy said! Just fascinating. I know you already piled the video full of information, but I remember the SR-71’s jet engines are started with the boron fuel, as well. Really cool-looking green flash at startup… Thanks again!

  42. Taladar2003

    It just occurred to me during your video that Formula 1 Grand Prix is the slow, boring, low energy version of F1 compared to the F1 rocket engine.

  43. Gerjan Jeuring

    Thank you for this fantastic video. It explains a lot of things I always wondered.!

  44. Robert Emerson

    One of mu favorite videos of yours so far. Thank you!

  45. Jan Mallory

    Scott, we’re pretty new to this stuff and we wonder why there are different mixtures in different rocket fuels…?

  46. Samaru Fly Fishing

    I had to watch this about 15 times before I could hear your words, I was too interested in all that pretty video.
    Anyway, I want to throw my hat in the ring for what to call the exhaust when it fans out in the upper atmosphere.
    Octopulsing. Kinda reminded me of an octopus.
    Anyway, carry on

  47. 4one14

    Another very informative and entertaining video Scott! I quite enjoyed all the quality clips of various launches and inclusion of technical docs showing both the beauty and the brains of rocket science. I love these type of vids and Kerbal explainers.
    If you could, it would be awesome if you made some longer format videos going a bit more in-depth on certain topics.
    Thanks for being awesome and making equally awesome content! <3

  48. Bertrand Thibodeau

    This is a great video! I’ve seen many of your vids and I have to admit, this is top-shelf! Keep up the great work!

  49. Spooks

    I fly High Powered rockets and our solid fuel is APCP, cool stuff!!

  50. BouncingBob

    i think the exhaust of the falcon 9 looks more like a jellyfish….. :D

  51. TheBlapman

    “Initiating payload cloaking device”
    *mic shuts off*
    *shouting in the control room*
    New announcer: “that was a joke, our camera feed experienced a glitch”
    *collective sigh of relief from cloaking engineers*

  52. Chico Rasia

    Nice video. I always thought the dark exhaust on the Saturn V footage was due to film solarisation.

  53. Ilya Glinsky

    Fascinating! Very informative and well done video. Thank you.

  54. Roger C

    Should it produce light, heat or sound? 🚀

  55. Caldwell Transport Columbus, GA

    This video is exhausting.

  56. Riccardo Basile

    2:39 Lol my gasdynamics professor used to call that flow configuration “sausage” configuration because of its shape

  57. LordCarpenter

    That was just awesome. Thanks for the explanation! :)

  58. indyjons321

    Learned a lot…. answered some questions I had…. I’d give it a 9.5/10

  59. Maynard Johnson

    Scott, would you consider doing a video about Jack Parsons?

  60. CJ Goth

    I used to work on the UK10 ion drive down in Farnborough. That had a beautiful exhaust which you could get a good look at in the 3m vacuum chamber.

  61. Shannon Taylor

    Thanks for this video Scott. I had always wondered why the shuttle engine exhaust looked the way it did and have never found an explanation till now. Cheers bro 😎

  62. pizda matii

    great video!
    but i missed the hot hydrogen exhaust of the NERVA engine and the eerie glow of an ion engine :) maybe in another video.

  63. Glenn Tillema

    I love your commentary but all of the slow motion rocket exhausts were real rocket pornography.

  64. Bo

    11 minutes of rocket engines in slow-mo? yes please

  65. Doug Ball

    Great explanation of a very complex topic. Care to tackle inlet compression for supersonic jets? :-)

  66. WDGFE

    How many times can an ablative engine be reused?
    My thinking was that it would require bell replacement after each flight, but I suspect I’m not correct about that.

  67. Dmytro Picky

    you are doing the work all space agencies failed to do! bless you!

  68. The Leonid

    *You Should try Space Fligth Simulator, 1.4 Update is here, It got A LOOOT Better.*

  69. Johnny Horan

    Why do the SRBs have those orange stripes?

  70. Kumquat Lord

    The exhaust from the RS-25 is GORGEOUS. It looks so clean and smooth, like I could touch it

  71. Pyrus Rex

    Scott, this is the video I’ve been waiting for you to make. The absolute best thing about rockets is the exhaust plume.

  72. sski

    The Saturn 5 is Slayer. All other rockets are Barry Manilow. \m/(><)\m/

  73. Tutor Daniel Wolf

    I think on the final version of the BFR (Raptor engine) there will be no green flame from the igniter because they plan to ignite the engine with some kind of electric arc. That makes things easier for mars missions: they dont have to bring igniter for the flight back to earth.

  74. Oddman1980

    So the reason the F-1 motors have that dark band… Is the gas generators are rolling coal.
    The ONLY time that’s ever been cool.

  75. Akshay Anand

    Ahh, Triethyl Borane… It’s the same stuff used to light the SR-71s J-58 engines. There’s a distinctive green burst as the fuel reacts with the TeB. It’s the same thing with the Raptor engine, except it’s happening at a much higher concentration of TeB.

  76. Benedict von Holtzendorff

    This channel is so god damn great.

  77. tubefish666

    53 FlatEarthers are disapproving this great lesson in rocket exhaust signatures :)

  78. Jim Henry

    Who else discusses rocket exhaust formulas?
    What range of temperatures are generated with the various fuels?
    I develop ultra high-temp coatings.

  79. Dominik Jage

    Damn Scott, this now one of my favourite videos on youtube.

  80. WineScrounger

    Ammonium perchlorate- a stable but very useful oxidiser.
    For further info on this tasty substance look up the Pepcon plant disaster.

  81. Enteraname

    Wow, great video! Can you do a video on engine gimbaling? Thx

  82. Filip Z

    I was here before he corrected the “the” to “they”

  83. jamaekjoo

    Congrats, very good video. I enjoyed it very much.
    Let add something interesting… The hydrogen fuelled rockets, like the ones at Space Shuttle, are not necessarily less bright exhaust flames than the solid fuel rockets at boosters. What happens is that when burning hydrogen, flame is ultraviolet, and humans are blind to this wavelength. In others words, hydrogen flames look invisible to us.
    Best regards from Madrid, Spain.

  84. William Chamberlain

    I thoroughly recommend finding a copy of the PDF of _Ignition!: An informal history of liquid rocket propellants_ by John D Clark: it’s an excellently technical and funny read on the various chemical rocket fuels/reactions, and their development from 1930s through to the end of the 1960s.

  85. B0BBYL33J0RD4N

    Well that was the best nerdgasm I’ve had this year.
    Fly safe good sire.

  86. Excalibruhhh

    Brilliant video mate! Some good explanations that were previous not so obvious for aerospace engineers as well.. if you could cover aerospike and other plug nozzles physics also, it would be great…

  87. - cparker3692 -

    Who else think rocket exhaust exiting the a rocket nozzle is one of the most satisfying thing in the world?

  88. Some Guy

    I’ve always wondered why rocket exhausts looked “the way the do”

  89. 104thDIVTimberwolf

    “Who doesn’t love the Saturn V?”
    The Soviets and Flat Earthers.

  90. Marco Tedaldi

    On Saturn V launches I especially like how the smoke billows up first and than gets sucked down really quickly as the engines power up…

  91. Cragified

    For some reason the nozzle extension cooling on the F1 combined with the fuel type just conveys the raw power of the thrust coming out of the motor. Seeing the streaking and able to see the exhaust gasses moving.

  92. Frank Roberts

    Thank you for answering the F1 exhaust “dark band” question that has bugged me for decades. I even learned something that I never suspected could possibly be true, that the pressure within the exhaust plume is below that of the ambient atmosphere. Of course, that makes perfect sense, it’s Bernoulli’s Principle in action. The faster a fluid flows, the lower it’s pressure becomes. It’s why airplane wings generate lift. I think we can agree that the exhaust gas is flowing at quite a clip, so it’s pressure has to be well below that of the surrounding air. Great video as usual sir.

  93. texaswilliam

    Whoa whoa whoa, that was a “mehthane” at 6:15 instead of a “meethane.” Ominous.

  94. Upcycle Electronics

    One of the current rocket companies looking to generate positive PR should pay Scott a fortune to do their broadcasts of launches. If Scott had full unrestricted access, complete artistic license, and he interspersed the kinds of material he creates all the time within an actual launch broadcast, I imagine there could be broad spectrum main stream appeal. In fact, I bet Scott could completely disrupt the market through the exponential increase in public exposure. Obviously there is a large potential audience interested in launches given the volume of viewers watching SpaceX launches. If Scott was handed a ×4-×5+ pay raise, and a small production crew, this would crush YT, and would probably wind up getting licensed for broadcast through corporate media. Imagine if launches were like small sporting events with corporations biding for broadcast rights instead of a PR department/company leaning on an expense account.
    I’d tune in to watch.

  95. WheresWa11y

    Disappointed – I read
    *Why Rocket Enthusiasts Look The Way The Do*
    Not what I got. 1 Star..

  96. 10mintwo

    A very notable color effect of kerosene fueled rockets that is left out here is how the overexpanded exhaust plume will turn a brilliant sapphire blue then aquamarine color just before cutoff when viewed at night. It is the molecular rovibrational band emission of carbon C2 radicals called Swan Bands after William Swan who discovered them in the 19th century while examining the spectra of carbon stars and some comets. It is the same cause of gas flames on a stove top being blue green. So while at low altitudes the unburnt carbon soot particles in the exhaust are hot enough to be optically thick prominent blackbody emitters, at high altitude the cooling rate of the low density plume is much higher, the soot falls below the Draper incandescence point much faster, and unmasks the true underlying light sea green color of all hydrocarbon flames. https://youtu.be/11xIQ_mlS2g?t=153

  97. Brian Wyters

    “Who doesn’t like the Saturn 5?”- Scott Manley
    The Soviets

  98. Atlas Hugged

    6:06 that Russian stealth payload fairing! You can’t hide the truth… unless it’s invisible!

  99. dougpowers

    11 minute lecture on rocket exhaust to start my Saturday? Yes please.

  100. Atomjonesy

    Damnit Scott, I could watch a 6 hour documentary about this stuff if you were to do it!

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