4 ms·

NEEMO

74 points by throwoutway 4y ago

bscphil 4y ago
I was surprised that the pressure at 62 feet is still low enough that the internal air can be exposed directly to the water without a controlled pressure differential. When I started reading I figured it was going to be something like a permanent submarine. I wonder if it's difficult to live under those conditions for weeks. Some video of the inside that also shows the water / air transition: https://www.youtube.com/watch?v=v3qqO8yQswg https://www.youtube.com/watch?v=v3qqO8yQswg
killjoywashere 4y ago
I know an anesthesiologist who did a dive medicine tour at NEEMO. The astronauts apparently have safety observers at all times. One of the weirder stories was their lavatory facility: the bathroom is fully continuous with the ocean, the water level is maintained by pressure. So when they have a bowel movement, they just squat in the water and do their business. And the fish know it. And swim right up to the orifice and a re eating the shit out of the astronauts as fast as they can push.
rippercushions 4y ago
The Aquarius article on Wikipedia has more details about the structure itself: https://en.wikipedia.org/wiki/Aquarius_Reef_Base https://en.wikipedia.org/wiki/Aquarius_Reef_Base And here's a 5-minute video tour: https://youtu.be/v3qqO8yQswg https://youtu.be/v3qqO8yQswg
tedlistens 4y ago
here’s a short motherboard video about NEEMO and asteroid missions :} https://www.youtube.com/watch?v=hl7msH2Swq4 https://www.youtube.com/watch?v=hl7msH2Swq4
travisporter 4y ago
“It is deployed on the ocean floor next to deep coral reefs 62 feet (19 m) below the surface.” Divers - would a breach be fatal at this depth?
- LeifCarrotson 4y ago
  They're at "depth pressure", so a small breach would not be an implosion but a dribble of bubbles ascending from the station accompanied by an equal volume dribble of water into the station. If so, they probably have time to employ whatever their normal ascent plan is. If they were at atmospheric pressure, it could be a calamitous, crushing implosion, but if they had warning, 20m down and back up is a fairly straighforward freediving depth (he says, having only accomplished 12m personally). Unfortunately, they're not at atmospheric pressure, they're at 3 bar. Recreational divers can be at this depth for about 35 minutes and then will ascend slowly at about 10 meters per minute. Longer or deeper, and they'd be required to perform decompression stops, which is a whole different, much more dangerous animal: handling emergencies that don't allow immediate ascent changes the risk level from driving a car (just pull over if something goes wrong) to flying an airplane. If you spend an hour at 20 meters, you'd need to pause for about 15 minutes at 3m below the surface (so close! but it's a logarithmic stackup), breathing gently from your SCUBA system at this reduced pressure, waiting for gasses to dissolve safely and slowly out of your bloodstream. None of the dive tables I have access to cover saturation diving, so ascent after more than an hour - after a day, a week, or more - isn't covered. So, assuming they have access to SCUBA gear, they should stop at roughly 9, 6, and 3m from the surface on the way up for increasing amounts of time. All that said, failure to ascend to the surface will eventually be fatal; humans can't breathe seawater. Taking chances with the bends risks air embolisms that may cause a stroke or heart attack and be fatal, but if might not get unlucky; it's worth taking a chance!
- bruce511 4y ago
  It occurs to me that what they could do with is a Mr-like "escape capsule". A diving bell, moored to the sea floor, with slight positive buoyancy, on a mechanical tether would allow the aquanauts to ascend slowly if there was any failure in the habitat. I've not seen any information that such a thing exists, but a low-tech device like this would seem to be a prudent idea. On the other hand the habitat is at 19m, so even a small amount of steel walls are unlikely to suffer an "unexpected breech."
- Gordonjcp 4y ago
  Not a diver, but recreational divers often go down to that sort of depth on compressed air without any ill effects. You'd need to ascend slowly and hang about at ten metres and five metres for about ten minutes to let nitrogen out of your system, to get back to the surface. It's about three times normal atmospheric pressure so it's not going to be ideal if there's an accident, but it's not like going to smash you flat with pressure, it's not going to Byford Dolphin you.
rkagerer 4y ago
To clarify for non-divers, the 62ft depth where this is located isn't considerably deep. Recreational divers regularly reach that. For comparison, the Navy's original SEALAB[1] habitats from the 60's were deployed at around 200ft and today's commercial saturation divers can work at depths of up to ~1000ft [2]. The fact they're staying there for long periods is significant, as well of course is the type of research and training they're doing. Saturation diving is common in the oil and gas industry. Sometimes they bring workers up in a sealed, submersible hyperbaric chamber and keep them at pressure in between dives to avoid wasting time decompressing after each work shift. Accidents can be gruesome[3], and accordingly the pay is considered good (e.g. US$1400/day). Here are other submerged habitats you can read about; there are even underwater hotels, restaurants etc. at shallower depths that you can visit: https://en.wikipedia.org/wiki/Underwater_habitat#Historical_underwater_habitats https://en.wikipedia.org/wiki/Underwater_habitat#Historical_... --- [1] https://en.wikipedia.org/wiki/SEALAB https://en.wikipedia.org/wiki/SEALAB [2] https://en.wikipedia.org/wiki/Saturation_diving#Depth_records https://en.wikipedia.org/wiki/Saturation_diving#Depth_record... [3] https://www.todayifoundout.com/index.php/2021/08/the-most-gruesome-death-the-byford-dolphin-accident/ https://www.todayifoundout.com/index.php/2021/08/the-most-gr...
classichasclass 4y ago
See also: https://en.wikipedia.org/wiki/Tektite_habitat https://en.wikipedia.org/wiki/Tektite_habitat

74 points by throwoutway 4y ago

I was surprised that the pressure at 62 feet is still low enough that the internal air can be exposed directly to the water without a controlled pressure differential. When I started reading I figured it was going to be something like a permanent submarine. I wonder if it's difficult to live under those conditions for weeks. Some video of the inside that also shows the water / air transition: https://www.youtube.com/watch?v=v3qqO8yQswg https://www.youtube.com/watch?v=v3qqO8yQswg

killjoywashere 4y ago

I know an anesthesiologist who did a dive medicine tour at NEEMO. The astronauts apparently have safety observers at all times. One of the weirder stories was their lavatory facility: the bathroom is fully continuous with the ocean, the water level is maintained by pressure. So when they have a bowel movement, they just squat in the water and do their business. And the fish know it. And swim right up to the orifice and a re eating the shit out of the astronauts as fast as they can push.

rippercushions 4y ago

The Aquarius article on Wikipedia has more details about the structure itself: https://en.wikipedia.org/wiki/Aquarius_Reef_Base https://en.wikipedia.org/wiki/Aquarius_Reef_Base And here's a 5-minute video tour: https://youtu.be/v3qqO8yQswg https://youtu.be/v3qqO8yQswg

tedlistens 4y ago

here’s a short motherboard video about NEEMO and asteroid missions :} https://www.youtube.com/watch?v=hl7msH2Swq4 https://www.youtube.com/watch?v=hl7msH2Swq4

travisporter 4y ago

“It is deployed on the ocean floor next to deep coral reefs 62 feet (19 m) below the surface.” Divers - would a breach be fatal at this depth?

LeifCarrotson 4y ago
They're at "depth pressure", so a small breach would not be an implosion but a dribble of bubbles ascending from the station accompanied by an equal volume dribble of water into the station. If so, they probably have time to employ whatever their normal ascent plan is. If they were at atmospheric pressure, it could be a calamitous, crushing implosion, but if they had warning, 20m down and back up is a fairly straighforward freediving depth (he says, having only accomplished 12m personally). Unfortunately, they're not at atmospheric pressure, they're at 3 bar. Recreational divers can be at this depth for about 35 minutes and then will ascend slowly at about 10 meters per minute. Longer or deeper, and they'd be required to perform decompression stops, which is a whole different, much more dangerous animal: handling emergencies that don't allow immediate ascent changes the risk level from driving a car (just pull over if something goes wrong) to flying an airplane. If you spend an hour at 20 meters, you'd need to pause for about 15 minutes at 3m below the surface (so close! but it's a logarithmic stackup), breathing gently from your SCUBA system at this reduced pressure, waiting for gasses to dissolve safely and slowly out of your bloodstream. None of the dive tables I have access to cover saturation diving, so ascent after more than an hour - after a day, a week, or more - isn't covered. So, assuming they have access to SCUBA gear, they should stop at roughly 9, 6, and 3m from the surface on the way up for increasing amounts of time. All that said, failure to ascend to the surface will eventually be fatal; humans can't breathe seawater. Taking chances with the bends risks air embolisms that may cause a stroke or heart attack and be fatal, but if might not get unlucky; it's worth taking a chance!
bruce511 4y ago
It occurs to me that what they could do with is a Mr-like "escape capsule". A diving bell, moored to the sea floor, with slight positive buoyancy, on a mechanical tether would allow the aquanauts to ascend slowly if there was any failure in the habitat. I've not seen any information that such a thing exists, but a low-tech device like this would seem to be a prudent idea. On the other hand the habitat is at 19m, so even a small amount of steel walls are unlikely to suffer an "unexpected breech."
Gordonjcp 4y ago
Not a diver, but recreational divers often go down to that sort of depth on compressed air without any ill effects. You'd need to ascend slowly and hang about at ten metres and five metres for about ten minutes to let nitrogen out of your system, to get back to the surface. It's about three times normal atmospheric pressure so it's not going to be ideal if there's an accident, but it's not like going to smash you flat with pressure, it's not going to Byford Dolphin you.

rkagerer 4y ago

To clarify for non-divers, the 62ft depth where this is located isn't considerably deep. Recreational divers regularly reach that. For comparison, the Navy's original SEALAB[1] habitats from the 60's were deployed at around 200ft and today's commercial saturation divers can work at depths of up to ~1000ft [2]. The fact they're staying there for long periods is significant, as well of course is the type of research and training they're doing. Saturation diving is common in the oil and gas industry. Sometimes they bring workers up in a sealed, submersible hyperbaric chamber and keep them at pressure in between dives to avoid wasting time decompressing after each work shift. Accidents can be gruesome[3], and accordingly the pay is considered good (e.g. US$1400/day). Here are other submerged habitats you can read about; there are even underwater hotels, restaurants etc. at shallower depths that you can visit: https://en.wikipedia.org/wiki/Underwater_habitat#Historical_underwater_habitats https://en.wikipedia.org/wiki/Underwater_habitat#Historical_... --- [1] https://en.wikipedia.org/wiki/SEALAB https://en.wikipedia.org/wiki/SEALAB [2] https://en.wikipedia.org/wiki/Saturation_diving#Depth_records https://en.wikipedia.org/wiki/Saturation_diving#Depth_record... [3] https://www.todayifoundout.com/index.php/2021/08/the-most-gruesome-death-the-byford-dolphin-accident/ https://www.todayifoundout.com/index.php/2021/08/the-most-gr...

classichasclass 4y ago

See also: https://en.wikipedia.org/wiki/Tektite_habitat https://en.wikipedia.org/wiki/Tektite_habitat