3 ms·

NB, for any budding bathynauts: carbon fibre is strong under tension, which is precisely the use-case for higher-than-ambient-pressure vessels such as air- and

NB, for any budding bathynauts: carbon fibre is strong under tension, which is precisely the use-case for higher-than-ambient-pressure vessels such as air- and space-craft. It's far less comparatively strong under compression, which seems to have been the principle failure mode of the now-permanently-submerged Titan. The failure modes of explosive vs. implosive failure are also relevant. High-pressure implosions tend to collapse the entire hull, whilst so far as I understand, explosive failure, particularly at the relatively low pressure differentials of air and space flight, tend to be localised, and the fibre-reinforced nature of composite materials should reduce damage to the neighbourhood of the initial failure point in many cases. Implosive failure needn't actually penetrate the hull so much as crease it, a mode which CF handles poorly respective to the application.

Terr_ 2y ago
I think a lot of people have a misconception that keeping pressure in is just as hard as keeping pressure out, while in some ways, it's probably easier to make a space station (keep 1 ATM in) than to make a submarine (keep 500 ATM out.) Hence sci-fi horrors is like getting sucked out into space through a pinhole.
- adgjlsfhk1 2y ago
  yeah, this is really one of my pet peeves. Lots of people like to pretend that holding a vacuum is really hard, but if all you need is a gross vacuum, it's only about as hard as going down 40 ft into the water.
  - eastbound 2y ago
    Other misconception: That we immediately die in space. You can probably survive a minute or two.
- euroderf 2y ago
  If a micrometeorite (or other space detritus) puts a pinhole in a wall in the space station, can you plug it by covering it with your finger, without necessarily losing the finger ?
  - Terr_ 2y ago
    IANASpaceDoctor, but very likely you can, at the possible expense of a space-hickey. Most of you would still be at the right pressure, and skin is pretty tough stuff.
written-beyond 2y ago
NGL my mind went straight to the Titan after I read "carbon fiber" and "ridiculously strong" in one sentence. Thank you for the clear explanation and for alleviating my anxiety of flying transcontinental again.
rcxdude 2y ago
Carbon fibre, like most composites, is also very hard to predict. It's much more complex to model, especially in terms of how it ages, and there's a lot of opportunity for part-to-patt variability, so even extensive testing doesn't necessarily give you an all-clear. It took a lot fo time and money to get carbon fibre to the same level of understanding as metals for use in airlines.

Terr_ 2y ago

I think a lot of people have a misconception that keeping pressure in is just as hard as keeping pressure out, while in some ways, it's probably easier to make a space station (keep 1 ATM in) than to make a submarine (keep 500 ATM out.) Hence sci-fi horrors is like getting sucked out into space through a pinhole.

adgjlsfhk1 2y ago
yeah, this is really one of my pet peeves. Lots of people like to pretend that holding a vacuum is really hard, but if all you need is a gross vacuum, it's only about as hard as going down 40 ft into the water.
- eastbound 2y ago
  Other misconception: That we immediately die in space. You can probably survive a minute or two.
euroderf 2y ago
If a micrometeorite (or other space detritus) puts a pinhole in a wall in the space station, can you plug it by covering it with your finger, without necessarily losing the finger ?
- Terr_ 2y ago
  IANASpaceDoctor, but very likely you can, at the possible expense of a space-hickey. Most of you would still be at the right pressure, and skin is pretty tough stuff.

written-beyond 2y ago

NGL my mind went straight to the Titan after I read "carbon fiber" and "ridiculously strong" in one sentence. Thank you for the clear explanation and for alleviating my anxiety of flying transcontinental again.

rcxdude 2y ago

Carbon fibre, like most composites, is also very hard to predict. It's much more complex to model, especially in terms of how it ages, and there's a lot of opportunity for part-to-patt variability, so even extensive testing doesn't necessarily give you an all-clear. It took a lot fo time and money to get carbon fibre to the same level of understanding as metals for use in airlines.