this post was submitted on 14 Sep 2024
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Space

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Becoming an astronaut is a fairly romanticized career path, but there are a lot of less-than-romantic aspects to working 50 miles or more above the Earth’s surface. Case in point: just being in zero G makes the human body do all sorts of embarrassing things.

A new story from the New York Times exhaustively points out that living in space comes with all sorts of “bodily indignities” which should give even the most eager potential space explorer pause. It turns out, it’s not just deadly radiation or muscle loss due to weightlessness astronauts traveling to spots in our own solar system will have to put with:

In microgravity, however, the blood volume above your neck will most likely still be too high, at least for a while. This can affect the eyes and optic nerves, sometimes causing permanent vision problems for astronauts who stay in space for months, a condition called spaceflight-associated neuro-ocular syndrome. It also causes fluid to accumulate in nearby tissues, giving you a puffy face and congested sinuses. As with a bad cold, the process inhibits nerve endings in the nasal passages, meaning you can’t smell or taste very well. (The nose plays an important role in taste.) The I.S.S. galley is often stocked with wasabi and hot sauce.

These sensory deficits can be helpful in some respects, though, because the I.S.S. tends to smell like body odor or farts. You can’t shower, and microgravity prevents digestive gases from rising out of the stew of other juices in your stomach and intestines, making it hard to belch without barfing. Because the gas must exit somehow, the frequency and volume (metric and decibel) of flatulence increases.

Other metabolic processes are similarly disturbed. Urine adheres to the bladder wall rather than collecting at the base, where the growing pressure of liquid above the urethra usually alerts us when the organ is two-thirds full. “Thus, the bladder may reach maximum capacity before an urge is felt, at which point urination may happen suddenly and spontaneously,” according to “A Review of Challenges & Opportunities: Variable and Partial Gravity for Human Habitats in L.E.O.,” or low Earth orbit. This is a report that came out last year from the authors Ronke Olabisi, an associate professor of biomedical engineering at the University of California, Irvine, and Mae Jemison, a retired NASA astronaut. Sometimes the bladder fills but doesn’t empty, and astronauts need to catheterize themselves.

Source: Jalopnik

New York Times article (paywalled)

e: spelling

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[–] [email protected] 118 points 1 month ago (2 children)

That is some interesting biology that SciFi tends to gloss over when dealing with microgravity

[–] [email protected] 65 points 1 month ago* (last edited 1 month ago) (4 children)

Oh, speaking of scifi, I read another article (which I cant find now, unfortunately) about space walks: astronauts can't just climb into a space suit and exit the space station, because that would cause decompression sickness. They have to undergo about 24 hours of preparation, then spend time in a decompression chamber once they re-enter the station. I can't find the article I read atm, but here's one from space.com that talks about it:

About 24 hours before the spacewalk, astronauts undergo decompression, the same procedure divers follow when returning from the depths of the ocean to the surface of the water. Inside the space station, air is pressurized to the same degree as it is on Earth at sea level: 14.7 pounds per square inch, or 1 atmosphere.

But inside a spacesuit it's 4.3 psi, according to NASA, which is about the same pressure experienced at 30,000 feet (9,000 meters) above Earth. Experiencing a rapid drop in pressure from 14.7 to 4.3 psi causes nitrogen bubbles to form in the bloodstream and get stuck, blocking blood flow — a condition known as "the bends" or decompression sickness. To avoid the condition, astronauts camp out the night before in a closet-sized airlock while wearing their space suit so their bodies have time to adjust to the change in pressure.

Source: Spacewalks: How they work and major milestones

e: Sandra Bullock would have died of decompression sickness pretty quickly.

[–] [email protected] 18 points 1 month ago* (last edited 1 month ago) (2 children)

Sci-fi spacesuits could be more advanced and maintain a higher internal pressure. The ones happening in the future at least.

[–] [email protected] 5 points 1 month ago (1 children)

Currently, higher pressure comes at the cost of reduced mobility. You're essentially fighting the suit whenever you close your fist or bend your knees.

[–] [email protected] 3 points 1 month ago

Which could be fixed in the future.

[–] [email protected] 5 points 1 month ago (1 children)

Hopefully some day we get mechanical counterpressure suits.

[–] [email protected] 3 points 1 month ago* (last edited 1 month ago) (1 children)

Haven't we built some working prototypes already, but they're just a hassle to put on and take off?

[–] [email protected] 4 points 1 month ago

Yup, and they have to be specifically tailored, and, even then, keeping them tight-fitting at joints is a challenge. There are some concepts with pressurized traditional gloves to work around some of that.

[–] [email protected] 13 points 1 month ago
[–] [email protected] 6 points 1 month ago

then spend time in a decompression chamber once they re-enter the station

Really? I thought going from low pressure to high pressure wasn't a big deal. Also, wouldn't that be recompression, rather than decompression?

[–] [email protected] 2 points 1 month ago

The bends doesn't necessarily kill you. It definitely can if the decompression is fast enough with a large pressure differential, but it can also cause pain or dizziness without death.

[–] [email protected] 7 points 1 month ago

Artificial gravity bypasses these problems and is also cheaper to film. Win-win!