Hydrofluoric acid is no joke. When I was younger, I worked in a wafer fab (a facility for making integrated circuits) and inadvertently got some 100% HF on the sleeve of my jumpsuit. I only noticed it after about 20 minutes when I saw that the material of the suit was flaking off and disintegrating. I didn't feel any pain until another 10 or 15 minutes while I was on the way to the hospital. The doctors had to inject my arm with a silver solution to try to get the HF to bond to that instead of my bones - my arm was ballooned out to about twice its normal, scrawny size due to the HF and the injected treatment. The pain was almost indescribable. They said I probably only got a few milliliters on me. I was VERY careful of HF after that.

"It is also hypergolic with such things as cloth, wood and test engineers." Drat, there goes my revolutionary plan to line a rocket's interior with test engineers.

"can you make us 100 pounds of dimethylmercury?" - You guys want 20 nukes with launch codes as an extra?

"fluorine is a better oxidizer than oxygen" this is one of those simple sentences that masks an absolute horror for basically any organic substance that doesnt want its oxygen ripped off.

That book taught me that rocket propellant researchers have similar ball diameter requirements as test pilots.

“Persuaded to huddle around a chlorine atom” is my favorite chemistry phrase.

Asbestos: “I’m fire proof.” Chlorine Trifluoride: “Hold my beer...”

I've always pictured one of those "IN CASE OF EMERGENCY, BREAK GLASS" boxes in the hallway, with a pair of running shoes behind the glass.

for all his success with propellants, Clark's proudest accomplishment was *zero* deaths for the program he ran for so many years.

I'd like an Audiobook version of that ... Read by Scott Manley!

Derek Lowe's 'Things I Will Not Work With' blog led me to Ignition. Also worth a read. A quote: "The general rule is, if you’re looking for the worst organic derivatives of any metal, you should hop right on down to the methyl compounds. That’s where the most choking vapors, the brightest flames, and the most panicked shouts and heartfelt curses are to be found. Methyl organometallics tend to be small, reactive, volatile, and ready to party."

“During the liquid rocket propellant era, a major incident involving ClF₃ occurred the first time a one-ton steel container was loaded with liquid ClF₃ for bulk shipment. The container had been cooled with dry ice to perform the liquid transfer and help make the product safer to handle, since the ClF₃ vapor pressure would only be about 0.007 kg/cm² (0.1 psia) in the subcooled state. However, the dry ice bath embrittled the steel container wall, which split while it was being maneuvered onto a dolly, instantaneously releasing 907 kg (2,000 lb) of cold ClF₃ liquid onto the building floor. The ClF₃ dissolved the 30 cm (12 inch) thick concrete floor and another 90 cm (36 inches) of gravel underneath the spill. The fumes that were generated (chlorine trifluoride, hydrogen fluoride, chlorine, hydrogen chloride, etc.) severely corroded everything that was exposed. One eyewitness described the incident by stating, ‘The concrete was on fire!’” -Safetygram 39: Chlorine Trifluoride © Air Products and Chemicals, Inc., 2004

Near the top of my list of things I never want to hear in real life: "the concrete is on fire" Next on Nile Red: how to make ClF3

My favorite phrase Clark uses in "Ignition!" is "spontaneous disassembly" for "explosion."

Rocket scientists: "What's the most dangerous chemicals we got? Put that in there. Yeah, and some cobra venom. And diamonds!"

I LOVE that book! And you didn't even mention the monopropellant madness! "Any intimate mixture of a fuel and an oxidizer is a potential explosive, and a molecule with one reducing (fuel) end and one oxidizing end, separated by a pair of firmly crossed fingers, is an invitation to disaster!" He then goes on about how the first monopropellant engines ran on nitroglycerin, and other monoprops that they had "never been able to fire them in a motor, since they invariably detonated before they could be poured into the propellant tank".

I'm a simple man, I see dangerous and rocket in the title I click.

One of my favourite lines from the book comes from the chapter on the experimental high-energy liquid monoprops: "On paper, it sounds ideal... But! Any intimate mixture of a fuel and an oxidiser is a potential explosive. And a molecule with one reducing (fuel) end and one oxidising end, separated by a pair of firmly crossed fingers, is an invitation to disaster". This humorously understated comment (in keeping with the rest of the book) confirms the fact that yes, quite a lot of early experimental propellant research involved the chemical equivalent of crossing one's fingers and hoping for the best!

Our catchphrase at XCOR was, "If you can't spill it on your shoe, we don't want to use it." During a pump test, Dan Delong actually detected a small LOX leak when his foot got cold, so he took his shoe off and let it warm up to allow the oxygen to dissipate- so it's a rule we really did use.

"It is hyperbolic with test engineers." How was THIS fact discovered? Aren't test engineers rather expensive to use as rocket fuel? "Hello, could you make 100 lbs of dimethyl mercury?" "Are you *INSANE*?"

You missed one nasty fuel ... Pentaborane (aka: the "green dragon")! A complex mixture of boron and hydrogen atoms with a nasty garlic smell, burnt with a brilliant green flame, and had acute toxicity that rivaled some nerve agents. And it was produced in massive quantities to be used as "zip fuels". The remaining unused kegs of the chemical were either burned off or dissociated with hot water / steam yielding hydrogen and far less toxic boric acid solution (the "dragon slayer" process). You briefly touched the subject of zip fuels in the XB 70 video in mid 2018.

"...a good pair of running shoes." LMFAO

Hi I work on the RL10 and back in the 60-70's Pratt an Whitney did extensive testing using the RL10 with hydrazine and fluorine. On the E-7 test stand (deactivated in 1974 torn down in 1995 still had hydrazine trapped in the 1000 gallon tank found out the hard way) We had a whole Fluorine passivation area to treat the hardware. I was to young but saw many test tapes ran very well but when it blew it did so impressively. They also did Hydrogen and fluorine, and hydrazine and oxygen. Take care.

Him: "If liquid Fluorine wasn't reactive enough, how about you try to put even more Fluorine in?" Me: "Oh, no, he's going to talk about Chlorine Trifluoride, isn't he?" Him: "Chlorine Trifluoride!" Me: "I knew it!"

7:15 When he said the words "metal flourine fire", the only thing I thought was RUN AWAY. And the author thought so too.

When I worked at Rockwell in eighties we lost a couple of engineers that were cleaning a rocket fuel tank, hydrazine (?) and forgot the safety requirements at KFC. Those kind of mistakes are fatal.

The most entertaining book on chemistry I’ve ever read. The section on hydrogen peroxide is a real eye-opener for anyone who thinks of this compound as merely the incredibly diluted solution sold in stores as a hair bleach or (somewhat incorrectly) as an antiseptic.

2:50 Liquid Ozone 4:50 Liquid Fluorine 5:55 ClF3 7:30 Li + H + F 8:15 Hg

Sand won't save you this time.

"Hypergolic with cloth, wood, and test engineers ..." cracked me up.

For discussion of more chemicals whose structures make you want to scratch out your eyes in horror, I would like to recommend a blog called "In The Pipeline," by Derek Lowe. Specifically, look for a series of entries under the category "Things I Won't Work With."

See chlorine triflouride on thumbnail *I CLICK* I was not disappointed

Hydrogen-fluorine combo: "... there is a niche for upper stages - where the rocket is far enough down-range that the exhaust" ... would be falling on _someone else._

I was eating cereal when he said about using liquid fluorine as a rocket fuel and I spat then choked in quick succession.

Ignition is a superb book, although I've only read the PDF version--didn't realise they'd reprinted it! Just ordered my copy now (Amazon UK aren't out of stock...).

Hah, I got hold of a digital copy some years ago. Excellent book. My favourite bit is probably the reaction test where two tiny droplets were placed on a watch glass and allowed to touch, and the reaction reduced the watch glass to powder. Talk about high explosive...

Is it just me or is Scott reading excerpts of this in his best kiddies bedtime rocket tales voice?

Toxic and explosive - how Kerbal!

Fifteen hundred comments so far. Enjoying reading some of them. For two years, 1965-67, I was a chemist at the Rocket Propulsion Laboratory, Edwards Air Force Base. Worked with much more dangerous chemicals than you mentioned. Shock sensitive explosives, and toxins like beryllium fluoride. One chemist, a Major, became incapacitated and had to retire. Two years were also spent contributing to the Skunkworks, 1963-65. That’s another story.

Awesome book! Interesting fact that the really vicious stuff tends not to be the fuel, but instead the oxidiser.

"...it is also hypergolic with things such cloth, wood and test engineers" You should defintiv do more voiceacting (like audiobooks), we will listen to you and enjoy for hours (or even days).

That book sounds like the opposite of "Fly Safe!" :)

I worked in the semiconductor industry as a technician. We used hydrofluoric acid in several processes. It is seriously nasty stuff, we used to have first aid drills SPECIFICALLY for hydrofluoric acid. We were told a palm print sized exposure was fatal. Every first aid kit in the whole 40 football pitch sized factory had calcium cream for hydrofluoric acid exposure.

With my (extremely limited) knowledge of chemistry: "Oh god, FLUORINE?! Are you INSANE?"

For a *really* nasty propellant, look up "Nuclear salt-water rocket" on Wikipedia... When I read this, my first thought was: "Could Dr. Strangelove please refrain from inventing stuff when he's *that* drunk...?"

"its like hunter s thompson but with a completely different kind of chemistry" XD

My thermo/gas dynamics and propulsion professor in the early '90s at Ohio State was Rudolph Edse, an honest-to-God German rocket scientist. While doing some background research in grad school, I found some reports he wrote in the '50s and '60s describing hilariously dangerous rocket fuel experiments that his research group at OSU did. IIRC, they did a couple tests of a hydrogen/fluorine fueled rocket engine in an empty lot across the river from campus before somebody asked them if they could please stop killing the grass...

“sweet, pungent, irritating, suffocating”... what ClF3 smells like according to Wikipedia. My question is: WHO THE HELL WOULD SMELL ClF3 ON PURPOSE?!

I always remember the dimethylmercury bit, its a potent reminder that what someone is asking for and what they want are two different potentially life saving things

Poor rattlesnakes in the desert.

I wonder if the book mentions the various types of nuclear rockets. Nuclear pulse propulsion, where you use nuclear bombs behind a pusher plate, would actually be fairly safe "fuels" to handle in the sense that the bomb devices would be hard to accidentally detonate. Nuclear thermal rockets like NERVA are a different story; once the reactor has gone critical the fuel becomes pretty lethal stuff to be around. My favorite has to be the nuclear salt water rocket, which uses an open cycle liquid fuel core. The liquid is basically water with uranium or plutonium salts dissolved in it, which are injected into a reaction chamber and mixed to become supercritical, heating the water to steam and blowing it out the nozzle as reaction mass, along with all the fission products. High Isp and high thrust, it's almost a torch drive but using it in atmosphere would be unconscionable, since it's basically a giant flying Chernobyl disaster.

Ordered the book in Feb direct from the publisher. Still waiting. :(. It has shipped though. Just turns out the remarkably low shipping price to the other side of the planet may have involved actual ships.

Reprinted ? My word, I have ordered it immediately! Ignition! is the best chemistry book I've read during my lifetime (on par with Gergel's "Excuse me sir, would you like to buy a kilo of isopropyl bromide ?")

Who wants a audio book or something on this channel where Scott reads this book and explains the more advanced stuff. Because I really wand that

I am distracted by your escape-towerless Saturn V

Yes indeed Scott, I checked this book out of the local library circa 1960's, now have two copies including a copy recently given to me as a gift from my best friend. Quotes like "hypergolic with sand,water and test engineers",You summed up the book well, Thank you - Ken

Great review of a very interesting book. I've always had a fascination with the darker side of chemistry (from my love of true crime) and I've heard of the lethality of some of these compounds before. I didn't realise there is such crossover in uses haha!!!

> one drop of dimethylmercury kills scientist "hey there ol pal could you make me 100 lbs and send it through the mail?"

Listening to the audiobook! It great! Scott - thank you so much for enlightening us and igniting our interest

Ah! I always wondered where that quote on Chlorine trifluoride came from, awesome video mate

chubbyemu has a good youtube video of that dimethylmercury incident you spoke of.

What could be worse than mercury paint? Mercury rocket fuel!

Thanks for your channel from a fellow Scot in Dunfermline. Keep keeping on. Luv and Peace.

1972 ! My gosh Scott you are a young lad. Born about the time I was getting out of submarines. Ethanol. - in my submarine days that was known as “torpedo juice” used as a propellant and commonly used by the crew for libations; if they could get away with it and if you were willing to suffer the wrath of the captain. I immensely enjoy your UKposts postings. Keep it up😊

This is really cool cause I just did a end of the year project on RP-1 fuel used in Space X and the chemistry behind it.

Let's add the famous quote from Isaac Asimov's foreword (I've seen a part of it on doors at the ESTEC ESA center in Holland): "Now, it is clear that anyone working with rocket fuels is outstandingly mad. I don't mean garden-variety crazy or merely raving lunatic. I mean a record-shattering exponent of far-out insanity. There are, after all, some chemicals that explode shatteringly, some that flame ravenously, some that corrode hellishly, some that poison sneakily, and some that stink stenchily. As far as I know, though, only liquid rocket fuels have all these delightful properties combined into one delectable whole."

Yes they finally print it again!!! I waited 4 years for this, made my day. This book was introduced to me by the same friend who introduced me to KSP and this channel.

Really really enjoyed this! thanks for taking the time to film it

6:00 "Putting more fluorine into the system" isn't the full story. Teflon, PFTE, has lots of fluorine, but makes for a horribly bad rocket fuel (even though it would allow the rocket to slide to the launch pad really easily...). No, what does matter is the reactivity of the fluorine. Fluorine itself tries very VERY hard to get an additional electron. And it is reactive exactly when it doesn't have one. Like in F2, where both fluorine atoms hold on to their electrons with the same strength, and in ClF3, where the central chlorine can hold on to its electrons pretty well too, making the Cl-F bonds tentative at best. On the other hand, if you have fluorine in a compound in which it has sated its hunger for an eighth electron, like in HF or in PTFE, it's fairly docile stuff actually, because you have to invest huge amounts of energy to get it away from that extra electron it has managed to grab...

There's a web comic that's been going for about 20 years now called freefall, it's about a genetically modified wolf working as a awrospace engineer in a teraformed planet. One of the characters as punishment is forced to work at a fast food restaurant and when asked what would happen if he quit is told he'd be forced to work at a chemical plant that produces clorine triflorideand then is told of it's hypergolic properties.

I've wanted a copy of that book since I read "Excuse me, sir ..." I'm surprised you omitted the ClF3 spill story, that is one of my favorite anecdotes.

Very enjoyable. Someone probably already did it but you'd be a great voice for an audiobook version :D Thanks for the very informative video.

Great vídeo!

Can you talk about aerospike engines? Curious droid did an excellent piece. I'd like to see what would change if it had to be widely adopted.

Thanks for the tip, my "ignition" book just came in today.

Right before I was born..... gawd, thanks for making me feel old, dude!!!

"..'reacts with Asbestos..." All I can say is 'Wow'. :o

But something more potent than alcohol was needed for the X-15 rocket-driven supersonic research plane. Hydrazine was the first choice, but it sometimes exploded when used for regenerative cool- ing, and in 1949, when the program was conceived, there wasn't enough of it around, anyway. Bob Truax of the Navy, along with 104 Winternitz of Reaction Motors, which was to develop the 50,000 pounds thrust motor, settled on ammonia as a reasonably satisfactory second best. The oxygen-ammonia combination had been fired by JPL, but RMI really worked it out in the early 50's. The great stability of the ammonia molecule made it a tough customer to burn and from the beginning they were plagued with rough running and combus- tion instability. All sorts of additives to the fuel were tried in the hope of alleviating the condition, among them methylamine and acetylene. Twenty-two percent of the latter gave smooth combustion, but was dangerously unstable, and the mixture wasn't used long. The com- bustion problems were eventually cured by improving the injector design, but it was a long and noisy process. At night, I could hear the motor being fired, ten miles away over two ranges of hills, and could tell how far the injector design had progressed, just by the way the thing sounded. Even when the motor, finally, was running the way it should, and the first of the series was ready to be shipped to the West Coast to be test-flown by Scott Crossfield, everybody had his fingers crossed. Lou Rapp, of RMI, flying across the continent, found him- self with a knowledgeable seat mate, obviously in the aerospace busi- ness, who asked him his opinion of the motor. Lou blew up, and de- clared, with gestures, that it was a mechanical monster, an accident looking for a place to happen, and that he, personally, considered that flying with it was merely a somewhat expensive method of sui- cide. Then, remembering something he turned to his companion and asked. "By the way, I didn't get your name. What is it?" The reply was simple. "Oh, I'm Scott Crossfield."

I don't often buy books on a whim, but this video had me go buy Ignition. Absolutely loving it, been making my commute very enjoyable! Now I wonder how much about liquid rocket propellants I'm actually leaning amongst the laughs in the book.

I was just going to mention I downloaded John Clark's book after seeing you mention it in your previous video and can't wait to get into it. I also downloaded Catch-22 by Joseph Heller at the same time and haven't read it before so i'm in two minds as to which to read first!

Rocket fuel has to be reactive but not too reactive :-) My copy of the book should arrive in early July.

Missed out on Hydrogen Peroxide. The Messerschmitt Me 163 Komet fighter fueled by it sometimes exploded on takeoff, sometimes exploded on landing, and sometimes just exploded.

Got my copy the other day, so happy to have it! I would love a more modern book someday as well.

Scott talking about explosive and highly toxic stuff is about the best vid i can watch before goin to bed

The channel "Today i found out" has put it best with their title: *_The "Nope" Chemical That is Chlorine Trifluoride_*

You should start a series where you read books for us.

Love that book so much. Stuck in my mind is that the essential escape equipment on some experiments should include "a good pair of running shoes"...

I love how his reading voice is the kind you would use to tell a 3 year old a bedtime story. The inflection and cadence makes me feel warm and fuzzy.

When you said liquid ozone, I visibly cringed at the thought. Edit; I spoke too soon, liquid fluorine made me audibly cringe.

well, the main advantage of ozone would be more energy density - because it is unstable - when burning a fuel on ozone you'd essentially get energy from the ozone decomposing to oxygen AND from the fuel burning with that oxygen thus potetially higher specific impulses - and yes, its also denser and thus takes up less space but hte necessities for storing it are impracitcal and yes - its also incredibly unsafe - there's a reason most of our atmosphere contains oxygen rather then ozone

Scott great book review. You’ve sold me. Cheers mate.

I loved your previous rocket fuel videos, now this is a new high

Sounds like Werner Kerman wrote a book.

what effect did the mercury have on performance, I'd imagine it would cool the exhaust but probably increase mass flow rate, but lower the specific impulse by lowering the kinetic energy of the exhaust products.

That sounds like it would be a great read. I like his mix of regular language while explaining and his sense of humor.

Alternate title for this video: "Scott reads from his new favourite book"

The moment I heard the words "Chlorine trifluoride" produced an audible whimper from me. Not enough NOPE in the world...

1k likes and 0 dislikes? HECK YEAH!

Love your videos, Scott! Let's watch this :)

I totally forgot about this book. I actually have a copy and started to read it a few years ago, but I never finished it. Time to change that. Thanks for reminding me.