What are Hypergolic Rocket Fuels? (Other than Explosive, Corrosive, Toxic, Carcinogenic and Orange)

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Hypergolic fuels are a core technology in rocket science, propellents that will spontaneously combust when mixed together. This makes them attractive for rocket designers, who generally aren’t the people who have to get in a the protective gear to load the stuff.
So, what are they made of, and why do designers pick one option over another?

  1. Chris Holt

    Fascinating summary Scott, thanks!

  2. RichTheWolfGaming

    Clean hypergols would be an awesome thing.

  3. LandeTLS

    Mmm. I love the smell of hydrazine in the morninggggg….gasp..dies

  4. Ray Ceeya

    Ugh, I work with nitric and phosphoric about once a week. Make sure you got your PPE on. That stuff stings.

  5. Exar

    so close to 1mil :)

  6. ShadowHunter120

    Id like my ignition systems and non hypertoxic fuels back please, I don’t want to mess with these horrible compounds…

  7. Drake Tamer

    I know a simple hypergolic fuel to put on rockets. My brain and all of these really long chemical titles. Plenty of heat and fumes.

  8. Thaddeus Lehman

    I am a chemist and I bought ignition after seeing your video. What a great book.

  9. Laust Bjerg

    Hi Scott. I like your videos a lot. I was thinking about how different thrusters work, and about how gimbaling on engines works. Just ideas for upcoming videos? Regards. Laust, Denmark

  10. DerAmeisen Koenig

    I’m so curious about what Rocket Lab will use for their Moon Orbit flights!

  11. Simply Space

    The Me-163 really didn’t fly safe. (Well… land safe)

  12. theonlydenis

    Dammnit had to buy a copy of Ignition for myself… first copy I gave to my aerospace engineer friend… who still hasn’t read it….

  13. Pyrus Rex

    I’m sad that good ol’ Aniline didn’t get any love here.

  14. R D

    yeah, thats a good amount of that.

  15. Rob Sin

    All we need is a warp drive.🖖🖖🖖🖖

  16. T4L0N57

    I was going to suggest a video on this. You read my mind. . . Or did I read yours??? I hear Twilight zone music… Creepy.

  17. Justice Royal Vieira

    You need a model NCC 1701 Enterprise model on your shelf behind you:)

  18. Doug Brower

    Thanks, Scott. A very professional and understandable video!

  19. Kineth1

    11:00 I’m glad we have started using new, clean mono-propellants; though I would be very much surprised if any country agreed to the use of new, clear propellants.

  20. Liam Beckett

    We need to get him to 1 million subscribers

  21. Allen Iverson

    You are amazing Scott I love space because of you bro

  22. Chris Musix

    I get my Hypergarlic fuels from Pizza Hut.

  23. Cmdr cletus

    You Sir, have wat too much information floating around in your coconut…..and we thank you for it.

  24. Henrik Nilsson

    Missed these types of videos from Scott lately. Happy it’s back.

  25. Stephen Irwin

    Great explanation, as always! Thanks.

  26. markotrieste

    Hypergolic fuels, when kerosene is the “clean” choice :-). Now sorry I have to mop an oxygen spill :D

  27. Matthew Litke

    My favorite is still CH3NO2

  28. Ashley Williams

    mmmm hyper garlic!

  29. L Dewey

    Fascinating stuff! Thanks for this interesting summary! 🚀💥💨

  30. iamthebeelzebub

    A lot of Europe is in a place right know where they would need someone from science instead of a politician.
    Know that I’ve made my nephews watch these videos of yours and they want to learn so much more.
    Yours sincerely iamthebeelzebub.

  31. mysock351C

    0:52 Gee, that molecule doesn’t look dangerous at all. No, really.

  32. 771

    Starliner escape thruster fuel: Ight imma head out

  33. Benjamin Lehmann

    Hi Scott. Thanks for the great content. Would you do a video on Reaction Engine’s recent success in testing their pre-cooler?

  34. MCRN ORB1T4L

    Hey it’s Scott ! Hello from France, Scott ! 👍

  35. Sam C 95

    As a chemist, love these chemistry videos! When I watched that Boeing launch abort test I recognised the gas as NO2, glad you’re here to explain how that came about because I was wondering!
    One small point – be careful how you use the terms “strong acid” and “weak acid” because although HF is very reactive it is not technically a strong acid. Strong acids are defined as acids that completely dissociate in water and HF does not because the bond is stronger and has more covalency due to better orbital overlap.
    Further to that, the 1% HF you’re talking about is described as a dilute acid because a weak acid is defined as an acid that does not fully dissociate in water.

  36. Michael Gallagher

    What a great voice & content! 😉

  37. pentagramprime

    Just learned what a methyl group is. Thanks Scott!

  38. Eric Omar Pabon Crespo

    Getting a PTS of Organic Chemistry. Still a great video!

  39. WillieRants

    Early congrats on 1M subs Scott, it won’t be long now. Thanks for all of the great info on our space programs.

  40. Brett

    Thanks. After one of your recent videos, I was left wondering about the term hypergolic.

  41. Mr Bill

    Thanks for the chemistry lesson Scott!

  42. Knut Der Große

    A controlled explosive chemical reaction…..

  43. Admiral Quality

    You left out “delicious”!

  44. Mimo

    The lighting was great and audio better! Content was fantastic as always too :D
    Top work!

  45. Chris Muncy

    Great as always Scott. I’m just finishing reading Ignition!: An Informal History of Liquid Rocket Propellants and absolutely love it. Fascinating read on the history of rocket fuels.

  46. ilcuggino

    Nice, a video on monopropellant should be very interesting too :D

  47. Alex Landherr

    Science Friday with Scott Manley!

  48. Murph

    Great vid, would like to have seen the Bloopers takes on all those long words :)

  49. Mick7sp

    The trick, William Potter, is not minding that your fuel could go kaboom !!!

  50. Robert Tonkli

    “There’s something called Tonka”. Cool!

  51. tinkmarshino

    Thanks again Scott.. I always wondered about fuels and their properties.. Great class.. I even took notes.. carry on, be safe and have fun doing it!

  52. Ryan McCall

    I sensed this video coming when I saw you discussing this on the Twitter

  53. pgo eds

    4:30 space shuttle in present tense – shall we tell him ?

  54. Tired Again

    All my hydrazine questions answered in one place!

  55. Cole Smith

    Just use “Monopropellant!” It will work with all of the OMS and ACS motos as well… SMH

  56. Snarky . Live

    Hydrazine is super scary, it’ll react you into a lovely vapor.


    It’s a good day when there’s a new Scott Manley video!

  58. Arnold Sherrill

    After hearing his presentation and watching it there is a lot of irony in the last two words he says: fly safe

  59. Dominic Jose

    The way he said “Fly Safe” was scary.

  60. Steve Robbins

    This reminds me of an incident that happened some time back in the 90’s when I worked at Rocketdyne in Canoga Park. Two scientists were killed in an explosion when they mixed some chemicals together. I don’t know what they were mixing, but the initial story was that they were doing rocket fuel research. Later, the truth came out; they were actually illegally disposing of hazardous chemicals by combustion, and the company used “research” as an excuse to get around environmental laws. This happened at the Santa Suzanna Field Laboratory, which we called “the hill”.

  61. TheRedstoneHive

    One nice thing is that their mach diamonds look beautiful!

  62. Al T

    Last time I was this early, the Dyna-Soar was still being researched

  63. Nathaniel Pool

    Isn’t, as the old saying goes: “everything is a hypergolic if the percent oxygen is high enough”

  64. 1_2_Die

    Classic Intro, GREAT =)

  65. Kuba Výmola

    2:41 reminded me the “Only the good” episode of Red dwarf, when Rimmer was trying to memorize the name of some compound and then trying to say it.

  66. Jelle Swaanen

    I like the fact that the conclusion at the end of ‘ignition’ mostly still holds up.


    No Kerbals were injured/killed during the making of this video.

  68. Chris Hayes

    Things spontaneously combusting seems to be a theme in rocket science.

  69. Jonas Hofer

    While watching OLF I thought.. 🤔 Hmm I wanna brush up on my knowledge about hypergolics.. Aaaaand Scott just released exactly this 👍

  70. Hey Siri

    Your video about propellants inspired me to start reading “Ignition!”, and I literally read the chapter you just covered today!

  71. Andy Foster

    It’s scary to see all these flasks of these chemicals so close together.

  72. Dan D

    ANY other person or YouTuber would require 1hour to explain it. Scott does the job in 11minutes with lots of it coming from his memory.

  73. Dildo Shwagins

    I took a lotta antihistamines and I’m just trying not to fall into my phone but I can oddly comprehend 90% of everything chemistry he’s sayin

  74. Tiisiphone

    More of the same in the book “Ignition!” It’s a fun book.

  75. justin h

    1:24 Someone needs to learn how to properly seal ampoules..

  76. nagualdesign

    If you have to wear a space suit _on Earth_ the design of your spacecraft may need rethinking.

  77. TeamwinFTW

    A really good book on these is called “Ingnition!”

  78. Bob Blum

    “Scott Manley, the hypergolucky guy!” (From “happy-go-lucky”, in case you’ve never heard the term before!)
    Excellent video as always, Scott, thanks!

  79. BlueJayRobin

    “If it weren’t dangerous, it wouldn’t be useful”.

  80. Christian Schärf

    Thank you Scott for this very informative video! I would, however, like to point one thing out: Hydrofluoric acid is not particularly strong, it is only about as strong (or, rather, weak) as citric acid. Despite this, it is dangerous to handle since it can penetrate the human skin. Additionally, it is the only acid able to corrode glass.

  81. Dead Baron

    Wrote out a long comment on the Me163 and of course you covered it! What an absolutely insane machine. Used two fuels that when mixed they ignited… and the pilot sat in between the tanks in the wings, and right in front of the primitive, unstable rocket motor.
    The Me163 had to be refuelled from two separate trucks that had to stay far away from each other to prevent even the fumes from mixing. One drop in the wrong place, any unnoticed spill before the other fuel was loaded, and BOOM. (One fuel type per wing, they couldn’t touch before reaching the rocket motor).
    You had to be a real mad lad to be on the ground crew, and clinically insane to be the pilot.

  82. Rok Adamlje

    3:20 when you dont really need wheels to land afterwards

  83. Lancaster Labs

    “The real name for Hydrazine is hard to say, but that’s the least of your problems” lol

  84. Br3ttM

    Using HF to protect the rocket plumbing from acid is like using Sodium Fluoride to protect teeth from acid, just a lot more extreme.

  85. harbl99

    4:10 — “Monomythyl Hydrazine”
    James Purefoy: “I hear that you are. Incredibly! Dangerous!”

  86. Patrick Holloway

    I like the word “Hypergolic”.

  87. JustSomeCanuck

    9:32 – and that’s how Scott Manley told North Korea what they were doing wrong…

  88. Nw0001rsp65

    Starting the weekend with Scott Manley!

  89. Mark MacDonald

    I loved this video. It reminded me of the time way back when I was a kid when I was playing with some friends and we accidentally made a hypergolic mixture. Some other kids had raided a chemical storage building and we had gallon jars of reagent grade acid in just about every basic variety. Quarter of a small test tube filled with nitric acid and other “stuff” went boom. Burned a hole in the ceiling and through one kid’s coat giving him the nastiest big green scab. We did a little research and figured out we’d accidentally made rocket fuel, but I had forgot about that until watching the fuming nitric acid in this video. Damn, I had a good childhood.

  90. Vallorn

    I’ve been reading Ignition! myself recently. Thank you for recommending it! It’s a fantastic book!

  91. Charles Lambert

    Smelly too, in the case of aniline.
    Edit: And no love for Britain’s RP-1/HTP engines?
    If you decompose the H2O2, the oxygen and steam are hot enought to be hypergolic with kerosene.

  92. NMCCW

    “Ignition!” occupies a special place in my library.

  93. fogllama

    As Derek Lowe once wrote in his ‘Things I Won’t Work With’ column, “There aren’t many gently sloping paths down to nitrogen gas.”

  94. knightmarex13

    ah Aerozine 50, the Arnold Palmer of hypergolics

  95. meldroc

    When the chemical you’re using to make your propellant safer is ***hydrofluoric acid***, that’s a rocket fuel I’ll take with a tall glass of nope!

  96. Kiithnaras Ashaa

    “Oh no, we spilled some liquid oxygen! What do we do?”
    “Shut off any ignition sources and leave the area. Just wait it out.”

  97. Dan B

    “and probably carcinogenic”
    “Probably”, likely because anyone exposed to the stuff likely died as a result of other nasty effects before living long enough to even develop cancer from it.

  98. Shrike DeCil

    This discussion can’t be complete without a plug for _Ignition: An informal history of liquid rocket propellants_ by John D Clark.
    There are an astounding array of things that can go very, very wrong. The hazmat suits are the least of everyone’s problems. At the very least, read about how everyone else has blown themselves up with whatever chemical you’ve decided is the new hotness.

  99. doinker50

    Does anyone else kinda feel like sometimes when Scott says “fly safe” its almost like a threat or ominous advice that a supervillian will give?

  100. Tim Berghoff

    Hypergolic fuels: Booms, Bangs and Bottles full of Nope since 1935.

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