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View Full Version : Toxicity of hypergolic fuels : is this a real problem ?



galacsi
2014-Oct-21, 05:10 PM
In the Proton thread "docmordrid" write this :


They are going to phase Proton out in favor of Angara because of the reliability issue and they want to get away from using toxic propellants. I've seen dates out as far as 2030, but doubt it'll last that long.

Then my question :

Is the toxicity of these toxic fuels a real problem ? I wonder because , they are so easy to store at ordinary temperature ,they are dense , then their tanks are small , they are hypergolic and the ISP is not so bad.
I understand that, for a recoverable rocket, toxicity is annoying , but for an ELV ?

Nicolas
2014-Oct-21, 06:27 PM
There's a lot of things to consider. One possibility (not sure if this actually is the case here): the Russians launch from other countries, for example Baikonur. If a rocket crashes during launch, they have heavily polluted a large area in a foreign country. The claims that could follow from that might be huge. It's bad enough if it happens in your own country.

JustAFriend
2014-Oct-23, 01:03 AM
There were stories of the German ME163 rocketplane (http://http://en.m.wikipedia.org/wiki/Messerschmitt_Me_163_Komet) leaking fuel and melting their pilots or exploding.

The US Titan missile (http://http://en.m.wikipedia.org/wiki/Titan_(rocket_family)#Accidents_at_Titan_II_silos) had problems, too.

docmordrid
2014-Oct-23, 01:36 AM
In the Proton thread "docmordrid" write this :



Then my question :

Is the toxicity of these toxic fuels a real problem ? I wonder because , they are so easy to store at ordinary temperature ,they are dense , then their tanks are small , they are hypergolic and the ISP is not so bad.
I understand that, for a recoverable rocket, toxicity is annoying , but for an ELV ?
Nitrogen tetroxide is a very strong oxidizer, and can damage flesh. Some materials that aren't rocket fuels ignite on contact with it.

Monomethylhydrazine is a strong toxin, very similar to that in poison mushrooms and totally capable of killing you. In addition to that it's a powerful skin irritant and has been claimed to be a carcinogen. Its relatives aren't much better.

Now imagine a few hundred tonnes of each falling on your town or village.

That's why China and Russia are phasing them out, both have had serious accidents, and one of the reasons the US is also phasing out hypergolics including, as mentioned above, the Titan IV.

galacsi
2014-Oct-27, 07:41 AM
Nitrogen tetroxide is a very strong oxidizer, and can damage flesh. Some materials that aren't rocket fuels ignite on contact with it.

Monomethylhydrazine is a strong toxin, very similar to that in poison mushrooms and totally capable of killing you. In addition to that it's a powerful skin irritant and has been claimed to be a carcinogen. Its relatives aren't much better.

Now imagine a few hundred tonnes of each falling on your town or village.

That's why China and Russia are phasing them out, both have had serious accidents, and one of the reasons the US is also phasing out hypergolics including, as mentioned above, the Titan IV.

Yes , accidents are always possible . Your answer makes sense.

Thank you

Jerry
2014-Oct-28, 05:28 AM
Having worked directly with hypergolic fuels, I can tell you it is no picnic. Rocket fuel requires bulk handling in very clean environments; and when a fuel is both highly toxic and explosive; laboratory verification of purity and system integrity is problematic: You cannot verify the system is safe without exposing test technicians to very real dangers that are difficult to mitigate.

Cruithne3753
2014-Oct-28, 08:36 PM
This is one thing that bugs me about SpaceX's Dragon 2. Will it need a hazmat team to clean up upon landing?

galacsi
2014-Oct-28, 09:18 PM
This is one thing that bugs me about SpaceX's Dragon 2. Will it need a hazmat team to clean up upon landing?

Well , wikipedia says
SuperDraco engines utilize a storable propellant (http://en.wikipedia.org/wiki/Storable_propellant) mixture of monomethyl hydrazine (http://en.wikipedia.org/wiki/Monomethyl_hydrazine) fuel (http://en.wikipedia.org/wiki/Fuel) and nitrogen tetroxide (http://en.wikipedia.org/wiki/Nitrogen_tetroxide) oxidizer (http://en.wikipedia.org/wiki/Oxidizer). so yes it will need a hazmat team. (like the litttle Boeing shuttle.)

An other point ,I learned , some hypergolic fuels are less toxic than other , like the ones used by I.O. S or some old french rockets. Fuming Nitric acid as the oxidizer and turpentine as the fuel. Nitric acid is not very good for your health but stable at current temperature and turpentine is not toxic. It comes from resine of Pine trees.

Van Rijn
2014-Nov-01, 12:21 AM
They'll need procedures like they had with the Shuttle for the OMS hypergolics. Keep in mind that this is, relatively speaking, a very small amount of material to handle compared to what's needed for a Proton.

publiusr
2014-Nov-01, 08:16 PM
What a hypergolic can give you is a smaller airframe for winged craft if you have the responsibility to use it properly.

I really liked the concept of the Martin Astrorocket:
"Both stages carry turbojets for powered landing and self-ferry between launch sites."
http://pmview.com/spaceodysseytwo/spacelvs/sld002.htm

The B-58 Hustler of shuttle concepts.

No huge chunks of nylon or rubber to catch in your engine throat for a hard start.
No giant high volume eggshell to try to attach wings to.