For those who are unaware: A couple billionaires, a pilot, and one of the billionaires’ son are currently stuck inside an extremely tiny sub a couple thousand meters under the sea (inside of the sub with the guys above).
They were supposed to dive down to the titanic, but lost connection about halfway down. They’ve been missing for the past 48 hours, and have 2 days until the oxygen in the sub runs out. Do you think they’ll make it?
My layperson understanding is that with space you only have to have something robust enough to keep the atmospheric pressure in (as well as other considerations of course) which allows for less robust materials. For deep sea exploration you need something robust enough to keep the water pressure out.
For additional info: 10 metres of water depth is approximately equivalent to 1 atmosphere’s worth of pressure (ATM) - so 50 metres is 5ATM and so on and so forth. So theoretically a submarine would have to combat hundreds of ATMs of pressure, whereas a space craft only has to combat at most a couple of ATM.
In the ISS a minor hole can be patched pretty easily and quickly as it’s a slow leak of air out, however if a leak occurs in a submarine the results can be explosive and deadly.
Thank you, yes this is what I had in my head, I appreciate you wording it properly, with examples!
To add a little: when a thing fails in compression (submarine), it’s usually unpredictable and catastrophic. When it fails in tension (spaceship), it starts slow and fails in a predictable way.
Tension is also much easier to calculate when you’re designing structures. Engineers will often go out of their way to make sure that tensile failure is the controlling failure mode, just to make sure that we don’t have to fuck with compression.