Kruunch answers “Scientific question - please do not read...”

Heike asked this question about Project Hail Mary:

Scientific question - please do not read if you have not already read the book! : : : One of the main problems is things escaping, but luckily they are not nitrogen resistant. But how could they escape in the first place when air in human environment is naturally 79% nitrogen? Did I miss something? He used an oxygen mask when he was injured, his air is not 100% oxygen in general. Then what it is made of?

Kruunch So the ISS runs Earth normal atmospheric pressure, thus it runs about the same oxy/nitrogen mix we find on Earth.

To make the constant EVAs work (norma…moreSo the ISS runs Earth normal atmospheric pressure, thus it runs about the same oxy/nitrogen mix we find on Earth.

To make the constant EVAs work (normally a 2.5 hour depressurization procedure) the author makes the ship have the same pressure as the suit (about a third of Earth normal), thus mitigating the need for depressurization for an EVA.

The issue here of course is to compensate for the lower pressure in EMUs, they are pumped with 100% Oxygen. NASA does that with the strict agreement the astronaut won't light a cigarette while on an EVA.

Now the problem with doing this in a ship/station is that there are a ton of metal parts in a low humidity setting. One spark and thar she blows!

(not to mention the author has the MC lighting a candle (parafin taper) not too far after explaining the lowered pressure of the ship).

It was the only real gotcha of the book that stood out to me (Andy Weir had a similar gotcha in the Martian with the air pressure effects on Mars)(less)

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Heike Thank you! So there was, indeed, a glitch in all of Andy's scientific ramblings. That's what I thought, nobody is perfect ;-) ...more
May 13, 2021 11:00AM · flag

Kruunch He explained the issue in the Martian as a story-telling construct and I took this to be the same.
May 13, 2021 11:13AM · flag

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Project Hail Mary

by Andy Weir (Goodreads Author)

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