What kind of oxygen astronaut breathe?

[Pawelk198604]

Once I heard that the Americans and the Russians have used pure oxygen into their spaceflight, lie deep sea diver, but after tragic accident of Cosmonaut Bondarenko, soviet stopped using it, and the American followed the suit after Apollo 1 fire, i wonder what kind of air mixture the using now?

[RainDreamer]

Pure oxygen can lead to oxygen poisoning. I think they mix with nitrogen gas, not sure the exact amount without looking up though.

[Tex_NL]

All this info is easy to find using google. If you actually know how to use google of course.

The space shuttle was the first American craft to use a regular air mixture, roughly 80% nitrogen and 20% oxygen. As far as I can find so does the ISS.

The Russian MIR also a similar air mixture but oxygen fluctuated between 20 and 40%.

[sgt_flyer]

You'll find all kind of answers here

https://en.m.wikipedia.org/wiki/Life_support_system

but basically, short duration mercury / gemini / apollo missions used pure oxygen at reduced pressure, and EVA suits also use partial pressure +pure oxygen (lighter life support + less reduced mobility from pressure stiffening for the suits.

Russians spacecrafts always used sea level air pressure with air like mix.

[tomf]

Divers don't normally use pure oxygen either. Below abput 6m depth in water 100% O2 becomes increasingly likely to kill you suddenly. Divers normally either breath air or mixes with slightly elevaetd levels of O2 like 32%.

[lajoswinkler]

First astronauts used pure oxygen so that the total pressure of the craft could be much lower than 1 atmosphere. That's not the case anymore and is also dangerous.

Deep sea divers certainly do not use pure oxygen as it would kill them. They use various mixes, depending on their diving procedure (depth, duration, etc.) such as heliox, trimix, nitrox, etc.

[kerbiloid]

Accident with Bondarenko took place not in a spacecraft, but in a soundproof decompression chamber during the training.

[KerikBalm]

O2 .... O- and O3 do very bad things to them...

Oh... you meant what kind of gas or air do they breathe?

[Bill Phil]

An oxygen nitrogen mixture, about 20:80.

But it on the suits it's pure oxygen. At a lower pressure.

If if I recall correctly Apollo slowly vented it's Nitrogen during launch. Could be wrong...