6 ms·

> Russian rockets use some nasty stuff Do you have a source for that? What sort of "stuff"?

rsynnott 8y ago
They probably mean hydrazine. The Russian Proton rocket uses it, though it’s being discontinued. This isn’t a uniquely Russian oddity, by the way; the European Ariane IV and US Titan IV were still in use into the last decade.
- baybal2 8y ago
  UDMH is not hydrazine, and is said to be worse as it doesn't biodegrade as readily as hydrazine. UDMH, hydrazine, and MMH are all very different beasts.
  - masklinn 8y ago
    UDMH and MMH are both hydrazine derivatives, classified as hydrazines, and either picked or mixed (Aerozine 50 is a 50/50 mix of hydrazine and UDMH) depending on the specific chemical and performance tradeoffs you want to make. UDMH, hydrazine and MMH are slightly different beasts.
- sandworm101 8y ago
  UDMH. This is why Musk can stand beside a crashed falcon rocket while a crashed russian rocket must be approached in suits.
  - sitharus 8y ago
    Depends on the rocket. The Soyuz main stage only uses refined kerosene, liquid oxygen and hydrogen peroxide. The upper stages almost always use some hydrazine compound, but that’s pretty common. Almost all satellites use a storeable propellant.
  - lostlogin 8y ago
    >must be approached in suits Locals make a living scavenging the toxic parts and have awful health problems as a result. http://blogs.discovermagazine.com/crux/2018/06/07/in-russia-spacecraft-land-in-your-backyard/#.W-hiYaSYaEc http://blogs.discovermagazine.com/crux/2018/06/07/in-russia-...
  - masklinn 8y ago
    As long as it didn't crash with a Dragon anyway (that uses MMH).
nicole_express 8y ago
I'm guessing they're referring to the hypergolic propellants used on the Proton rocket? Which are, indeed, notoriously toxic. In which case, they're not something SpaceX has shyed away from; they are indeed not used on the Falcon, but hypergols will power the SuperDraco engines on the Dragon 2. When you need storable propellants (either for a launch escape system that needs to be ready to go at any time, or for ICBMs that can be kept in a launch-ready state), and a solid rocket won't do for whatever reason, there's just nothing else that will do the job.
- avmich 8y ago
  > When you need storable propellants (either for a launch escape system that needs to be ready to go at any time, or for ICBMs that can be kept in a launch-ready state), and a solid rocket won't do for whatever reason, there's just nothing else that will do the job. That is, if you don't count Soyuz landing capsule, which carries about 30 kg of hydrogen peroxide and keeps that for up to 210 days flight before landing. And if you don't count Zarya spacecraft, which - never built, but was designed to use hydrogen peroxide for powered landing ( https://en.wikipedia.org/wiki/Zarya_(spacecraft) https://en.wikipedia.org/wiki/Zarya_(spacecraft) ), also after long flights. And Buran spaceplane, which used LOX and kerosine for maneuver engines able to word in a month-long flight. And Kliper spacecraft designs with propulsion on LOX and ethanol. Even hydrogen can be made working after weeks of flight if you have large enough tanks - there was design of upper stage of N-1 with that. With Lockheed works on space tanker ( https://en.wikipedia.org/wiki/Advanced_Cryogenic_Evolved_Stage https://en.wikipedia.org/wiki/Advanced_Cryogenic_Evolved_Sta... ) the time range can be extended even more. I think we can leave those toxic propellants aside when we want.
aphextron 8y ago
>Do you have a source for that? What sort of "stuff"? Russians are still using hypergolic fuels rather than the methane/oxygen that most new generation launch vehicles are using.
- avmich 8y ago
  Those methane-based launchers all have not yet left the design stage.
tim333 8y ago
Probably UDMH and nitrogen tetroxide or nitric acid referred to as Devil's Venom in Russia apparently https://en.wikipedia.org/wiki/Devil%27s_venom https://en.wikipedia.org/wiki/Devil%27s_venom The same mix was what blew up in Damascus Titan missile explosion as told in the book Command and Control. Luckily the 9-megaton warhead didn't go off. I recommend the book Ignition if you are interested in these things (free pdf http://library.sciencemadness.org/library/books/ignition.pdf http://library.sciencemadness.org/library/books/ignition.pdf)
- scottlocklin 8y ago
  That book is one of the best things ever. " And if you, gentle reader, have never seen a nervous rocket mechanic, complete with monkey suit, being buzzed by nine thousand demented bats and trying to beat them off with a shovel, there is something missing from your experience."

They probably mean hydrazine. The Russian Proton rocket uses it, though it’s being discontinued. This isn’t a uniquely Russian oddity, by the way; the European Ariane IV and US Titan IV were still in use into the last decade.

baybal2 8y ago
UDMH is not hydrazine, and is said to be worse as it doesn't biodegrade as readily as hydrazine. UDMH, hydrazine, and MMH are all very different beasts.
- masklinn 8y ago
  UDMH and MMH are both hydrazine derivatives, classified as hydrazines, and either picked or mixed (Aerozine 50 is a 50/50 mix of hydrazine and UDMH) depending on the specific chemical and performance tradeoffs you want to make. UDMH, hydrazine and MMH are slightly different beasts.
sandworm101 8y ago
UDMH. This is why Musk can stand beside a crashed falcon rocket while a crashed russian rocket must be approached in suits.
- sitharus 8y ago
  Depends on the rocket. The Soyuz main stage only uses refined kerosene, liquid oxygen and hydrogen peroxide. The upper stages almost always use some hydrazine compound, but that’s pretty common. Almost all satellites use a storeable propellant.
- lostlogin 8y ago
  >must be approached in suits Locals make a living scavenging the toxic parts and have awful health problems as a result. http://blogs.discovermagazine.com/crux/2018/06/07/in-russia-spacecraft-land-in-your-backyard/#.W-hiYaSYaEc http://blogs.discovermagazine.com/crux/2018/06/07/in-russia-...
- masklinn 8y ago
  As long as it didn't crash with a Dragon anyway (that uses MMH).

nicole_express 8y ago

I'm guessing they're referring to the hypergolic propellants used on the Proton rocket? Which are, indeed, notoriously toxic. In which case, they're not something SpaceX has shyed away from; they are indeed not used on the Falcon, but hypergols will power the SuperDraco engines on the Dragon 2. When you need storable propellants (either for a launch escape system that needs to be ready to go at any time, or for ICBMs that can be kept in a launch-ready state), and a solid rocket won't do for whatever reason, there's just nothing else that will do the job.

avmich 8y ago
> When you need storable propellants (either for a launch escape system that needs to be ready to go at any time, or for ICBMs that can be kept in a launch-ready state), and a solid rocket won't do for whatever reason, there's just nothing else that will do the job. That is, if you don't count Soyuz landing capsule, which carries about 30 kg of hydrogen peroxide and keeps that for up to 210 days flight before landing. And if you don't count Zarya spacecraft, which - never built, but was designed to use hydrogen peroxide for powered landing ( https://en.wikipedia.org/wiki/Zarya_(spacecraft) https://en.wikipedia.org/wiki/Zarya_(spacecraft) ), also after long flights. And Buran spaceplane, which used LOX and kerosine for maneuver engines able to word in a month-long flight. And Kliper spacecraft designs with propulsion on LOX and ethanol. Even hydrogen can be made working after weeks of flight if you have large enough tanks - there was design of upper stage of N-1 with that. With Lockheed works on space tanker ( https://en.wikipedia.org/wiki/Advanced_Cryogenic_Evolved_Stage https://en.wikipedia.org/wiki/Advanced_Cryogenic_Evolved_Sta... ) the time range can be extended even more. I think we can leave those toxic propellants aside when we want.

aphextron 8y ago

>Do you have a source for that? What sort of "stuff"? Russians are still using hypergolic fuels rather than the methane/oxygen that most new generation launch vehicles are using.

avmich 8y ago
Those methane-based launchers all have not yet left the design stage.

tim333 8y ago

Probably UDMH and nitrogen tetroxide or nitric acid referred to as Devil's Venom in Russia apparently https://en.wikipedia.org/wiki/Devil%27s_venom https://en.wikipedia.org/wiki/Devil%27s_venom The same mix was what blew up in Damascus Titan missile explosion as told in the book Command and Control. Luckily the 9-megaton warhead didn't go off. I recommend the book Ignition if you are interested in these things (free pdf http://library.sciencemadness.org/library/books/ignition.pdf http://library.sciencemadness.org/library/books/ignition.pdf)

scottlocklin 8y ago
That book is one of the best things ever. " And if you, gentle reader, have never seen a nervous rocket mechanic, complete with monkey suit, being buzzed by nine thousand demented bats and trying to beat them off with a shovel, there is something missing from your experience."