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That’s slightly misleading. Originally they put 1 atmosphere of pure O2 in the Apollo capsule. This proved to be a great environment for fires. After that they
by ls612 8y ago
That’s slightly misleading. Originally they put 1 atmosphere of pure O2 in the Apollo capsule. This proved to be a great environment for fires. After that they pressurized the capsule with 5 psi of pure O2, which is about 1/3 atmospheric pressure.
- andy_ppp 8y agoWhat’s wrong with air is what I’m asking? Are the pressures in the cabin too extreme?
- empyrical 8y agoIf you're wondering why there wasn't nitrogen mixed in, it's because the additional systems+tanks for handling nitrogen would've added more weight to the spacecraft. This video goes in to a bit more detail: https://www.youtube.com/watch?v=FvA7N_j_8os https://www.youtube.com/watch?v=FvA7N_j_8os
- jimbosis 8y agoThese two articles talk about this question: https://www.popsci.com/why-did-nasa-still-use-pure-oxygen-after-apollo-1-fire https://www.popsci.com/why-did-nasa-still-use-pure-oxygen-af... https://www.space.com/17338-apollo-1.html https://www.space.com/17338-apollo-1.html
- _Microft 8y agoReducing the pressure reduces the forces on the pressure vessel. I assume that only the oxygen partial pressure is actually important for respiration.
- grkvlt 8y agoInterestingly, that's higher than the ppO2 at sea level, which is about 3 psi, or at ~5K feet (standard airliner cabin pressure) where it's 2.5psi, so they were still running at almost double the amount of oxygen available normally.