Most Dangerous Spacecraft Fuel

[Voyager275]

Is hydrazine the most dangerous fuel used in spacecrafts? I remember that the Apollo astronauts during Apollo-Soyuz almost died due to a leak.

[Kryten]

UDMH, as used most notably in all stages of Proton, has similar effects to hydrazine but with about twice the toxicity for acute exposure.

[Kerbal01]

UDMH is hydrazine (Un-Symmetirical Dimethel Hydrazine)

[K^2]

I would vote for anything mixed with Chrlorine Trifluoride. Supplementary reading.

[Nothalogh]

Is hydrazine the most dangerous fuel used in spacecrafts? I remember that the Apollo astronauts during Apollo-Soyuz almost died due to a leak.

Monatomic hydrogen, a true hypergolic monopropellant

Either that or some exotic borane+interhalogen mix

[clivman]

Well an Orion Drive would have pretty dangerous fuel:confused:

[Jovus]

I'm gonna have to go with UDMH/HNO3. Are there other, more dangerous fuels on paper? Sure. But tally actual deaths.

[NuclearNut]

Well an Orion Drive would have pretty dangerous fuel:confused:

To handle? Not really, properly designed nuclear bombs require precise conditions to actually detonate. Now to watch the launch without glasses would be quite a danger to your vision, and being downwind from a ground launch would be a really, really bad idea, but otherwise the fuel itself is not that terribly deadly. Regrettably (or fortunately, dependent your point of view) we have not launched any so it is not an existent rocket.

Now for actual rockets? Well hydrazine is quite nasty, so is chlorine trifluoride, but I would give the cake to good ol LOX, explosive on contact with most things, when cooled causes air to turn to liquid around it. While not in itself nasty, it seems to be used quite extensively in rocket engines. I know, I know, not a toxic or particularly nasty thing as far as it goes, but hey, it beats the others in volume.

[CptRichardson]

No, I'm pretty sure the most dangerous fuel is LOX. You know, with that whole pesky 'turns anything into high explosives under the right conditions' thing. And being able to freeze body parts off, and being able to boil to the point of popping crafts (see poor, dumb SpaceX), or the fact that it's basically pure fire waiting for a reason to happen...

[Nothalogh]

No, I'm pretty sure the most dangerous fuel is LOX. You know, with that whole pesky 'turns anything into high explosives under the right conditions' thing. And being able to freeze body parts off, and being able to boil to the point of popping crafts (see poor, dumb SpaceX), or the fact that it's basically pure fire waiting for a reason to happen...

Let's not forget the ability to turn kerosene into high explosive jello pudding, one of the early Atlas SM-65s was lost that way, engine failed to start, oxyliquit formed in the flame trench, 2nd engine start succeeded, followed by the flame trench detonating

[sgt_flyer]

Guess what was tested back then in 1967 has the edge in dangerosity... (Though, hopefully, this combination is so difficult to do outside of test benches that it's not really adaptable)

https://www.flightglobal.com/pdfarchive/view/1967/1967%20-%200069.html

Tripropellant Lithium - fluoride - hydrogen rocket engine tested in the 60s... - 542 ISP !

But uses : liquid hydrogen (to be kept below 23°K) liquid lithium (to be kept above 453K - speak about insulation problems in a rocket ) and liquid fluoride...

Imagine the care needed with liquid lithium... (AKA absolutely 0 humidity nor contact with oxygen allowed)

Plus fluoride to be safely kept

[Streetwind]

Tripropellant Lithium - fluoride - hydrogen

Jeebus Christ in a camper van! What were they thinking?!

Reminds me of one of Jeff Goldblums quotes from Jurassic Park.

"Your scientists were so preoccupied with whether or not they could, they didn’t stop to think if they should."

[sgt_flyer]

Well, they wanted to see what was the best ISP they could achieve with only chemical reactions of 'classic' atoms / molecules (stuff like metallic hydrogen are a bit outside classic chemical reactions ) - though here, the downsides far exceeds the upsides (imagine the enormous costs to build and maintain a facility capable of safely fueling (yeah with moving fluoride and hot lithium through fuel pipes ^^) and launching such a thing... Yup, LH2-Lox seems far safer (and cheaper) in comparison

Edited October 8, 2015 by sgt_flyer

[Mad Rocket Scientist]

Nuclear bombs. Nothing can really compete with that.

[Kryten]

Nuclear bombs. Nothing can really compete with that.

I can quite confidently say that nobody has been killed, injured, or in any way inconvenienced by use of nuclear bombs for space propulsion.

[Mad Rocket Scientist]

I can quite confidently say that nobody has been killed, injured, or in any way inconvenienced by use of nuclear bombs for space propulsion.

True, but danger is potential harm, not actual harm. Still, though, if it's not used for fuel regularly, then it's not very dangerous.

[NuclearNut]

True, but danger is potential harm, not actual harm. Still, though, if it's not used for fuel regularly, then it's not very dangerous.

Honestly I would rather be sitting right next to a modern nuclear bomb that is unarmed than a Tripropellant Lithium - fluoride - hydrogen fuel tank, or hydrazine for that matter. One I can hit with a hammer and be fine with, the others would not end well for me or the block I live in.

[Hannu]

I think that chlorine trifluoride wins this competition. Liquified fluorine and ozone are also nasty things but not as bad. Pure ozone is unstable even in cryogenic state but there has been tests with mixed oxygen and ozone. Nuclear bombs sound bad but they are extremely reliable devices. As far as I know any nuclear bomb has never exploded unintentionally. Dangerous chemicals are much less predictable. They cause corrosion, can explode spontaneously in some conditions, leaks are extremely poisonous or fire hazardous etc. There are good reasons why extreme stuff have not used in modern rockets. Unfortunately there are situations where hydrazine variants are only practical possibilities.

[Kryten]

I think that chlorine trifluoride wins this competition.

Nobody has ever used or seriously proposed to use chloride trifluoriude in a rocket engine, people just keep bringing it up with the same set of anecdotes for no good reason. The closest we've ever gotten are soviet tests of an ammonia/fluorine upper stage.

[sgt_flyer]

Oh they did made test bench versions of those rocket engines Chloride trifluoride + hydrazine nontheless

http://naca.central.cranfield.ac.uk/reports/1949/naca-rm-e9f01.pdf

But as with the tripropellant, the problems still far outweight the benefits (not the least that the oxyded layer must remain intact within the fuel tank )

Edited October 11, 2015 by sgt_flyer

[SargeRho]

Fuel that has been used? Hydrazine. Fuel that could be used? Antimatter.

[cantab]

I'm gonna have to go with UDMH/HNO3. Are there other, more dangerous fuels on paper? Sure. But tally actual deaths.

If you're counting deaths and injuries then it may well go to black powder, because any idiot can buy a firework and get themselves injured by it.

[Hannu]

Nobody has ever used or seriously proposed to use chloride trifluoriude in a rocket engine, people just keep bringing it up with the same set of anecdotes for no good reason. The closest we've ever gotten are soviet tests of an ammonia/fluorine upper stage.

OK. He really asked most dangerous fuel used in space, but I took tested compounds into account. I did not found documents about actual use of these soviet NH3/F2 engines. They developed engines nearly production ready state but never allowed to use them.

http://www.astronautix.com/props/lf2monia.htm

It seems that most dangerous stuff which is really used in real spacecrafts are hydrazine variants. More dangerous and exotic chemicals have been tested on Earth but not flown in space.

[problemecium]

Nope.

Admittedly as far as I've checked, it hasn't been used for actual production models of rockets (for good reason), but research was done into mixing conventional fuel (e.g. kerosene) with Methylmercury in order to increase the thrust at the cost of Isp.

Methylmercury is so toxic that during once incident during R&D, when a lab worker accidentally spilled a small amount on her rubber glove, immediately took off the glove, and washed her hand... she died from mercury poisoning.

[Voyager275]

Nope.

Admittedly as far as I've checked, it hasn't been used for actual production models of rockets (for good reason), but research was done into mixing conventional fuel (e.g. kerosene) with Methylmercury in order to increase the thrust at the cost of Isp.

Methylmercury is so toxic that during once incident during R&D, when a lab worker accidentally spilled a small amount on her rubber glove, immediately took off the glove, and washed her hand... she died from mercury poisoning.

I read about that, nasty stuff methylmercury is