132
Titan sub: crew have died after catastrophic loss of pressure chamber, US Coast Guard confirms
(www.theguardian.com)
this post was submitted on 22 Jun 2023
132 points (100.0% liked)
World News
22058 readers
59 users here now
Breaking news from around the world.
News that is American but has an international facet may also be posted here.
Guidelines for submissions:
- Where possible, post the original source of information.
- If there is a paywall, you can use alternative sources or provide an archive.today, 12ft.io, etc. link in the body.
- Do not editorialize titles. Preserve the original title when possible; edits for clarity are fine.
- Do not post ragebait or shock stories. These will be removed.
- Do not post tabloid or blogspam stories. These will be removed.
- Social media should be a source of last resort.
These guidelines will be enforced on a know-it-when-I-see-it basis.
For US News, see the US News community.
This community's icon was made by Aaron Schneider, under the CC-BY-NC-SA 4.0 license.
founded 2 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
Not actually correct in this case. Hypoxia is only painless if oxygen is displaced with an inert gas like nitrogen. Our bodies detect low oxygen indirectly via chemoreceptors that detect the increase in blood acidity (respiratory acidosis) induced by high carbon dioxide (hypercapnia).
As humans breathe in a sealed environment, oxygen is replaced with CO~2~. Hypercapnia is what causes the panic and pain of drowning prior to inhalation of water. Consciousness is lost mere seconds after water inhalation.
Drowning and hypercapnic asphyxiation are essentially the same experience in terms of suffering.
Secondary outcomes and resuscitation are a different story, but are obviously not applicable here.
Okay, so I am gonna check those two off my lists of ways I want to die.
I think I read something about the sub having a CO2 scrubber which would mean their bodies wouldn't feel the lack of oxygen due to what you explained, but I know nothing about this.
This is a good question! Not sure which precise units they had and in what quantity, but given the size of the Titan (no way they can support liquid regenerative system with their size and energy reserve constraints), they would have had canister containing solid CO~2~ adsorbent with a fan (example).
Without the fan, it's not going to be very effective since CO2 has to actually pass over the solid. Passive diffusion is not going to move the same volume of CO2 over the solid even if the solid was removed from the housing. Even if they didn't run out of battery, The solid has a maximum capacity - about 7.5 kg for the unit linked above. Even with reserve capacity, an average human exhales ~0.97 kg of CO~2~ per day.
O~2~ to CO~2~ exchange via respiration is mole for mole (you do lose a little mass in carbon and water just by breathing!). Atmospheric CO~2~ is 0.041% (410 ppm) and O~2~ is a hair under 21% and that's the standard to which life support systems are held. Humans lose consciousness at around 3.7% oxygen, but experience hypercapnia at >6% CO~2~. (Physiology nerds - I converted from the partial pressures in mmHg to % of 1 atm for comprehension)
So in this hypothetical scenario, hypercapnia would definitely precede loss of consciousness due to anoxia.