A terrifying thing happens to your nails after a space walk: ScienceAlert

A terrifying thing happens to your nails after a space walk: ScienceAlert

Let’s face it, going into space wreaks havoc on the human body. We have evolved in the Earth’s environment, over hundreds of millions of years; So, remove the Earth environment and things start to go awry.

There is a loss of bone and muscle density. There are vision problems due to too much fluid in the brain; Without gravity, bodily wetness is free to float in there willy-nilly. There is a problem urinating. It turns out that gravity is absolutely essential to our sense of when we need to urinate. It’s possible that there is erectile dysfunction (and it’s not the reason you think).

In a particularly bizarre downside of spaceflight, after an extravehicular activity (EVA), more commonly known as a spacewalk, a surprising number of astronauts’ toenails fall off.

Yes. It’s disgusting. The technical term is onycholysis and the problem appears to be more related to atmospheric pressure than gravity.

In space, there is very little ambient pressure, which is not good for the human body. To be as safe as possible during EVA, an astronaut’s suit must be pressurized. So far, so good. But when it comes to the hands, this becomes a problem.

NASA astronaut Anne McClain shows off her spacesuit glove in 2019. (NASA)

“Hand injuries are common among astronauts training for extravehicular activity (EVA),” a team led by epidemiologist Jacqueline Charvat of Weill Laboratories wrote in a 2015 conference paper.

“When gloves are compressed, they restrict movement and create pressure points during tasks, sometimes resulting in pain, muscle fatigue, abrasions, and sometimes more serious injuries such as onycholysis. Glove injuries, both anecdotal and recorded, have been reported during EVA training “And flying consistently throughout NASA’s history regardless of mission or glove model.”

An EVA can spend a very long day stuck in a spacesuit – the longest ever recorded was 8 hours and 56 minutes. (Yes, before you ask, there is a solution to the problem of peeing in a spacesuit.) That’s a long time to wear gloves that can cause and worsen hand injuries.

Hands are very important, especially if you’re doing manual tasks outside the space station that can’t be done any other way. Much thought has been given to this problem. As Charvat and her team note, this seems to happen regardless of the glove’s design. Figuring out exactly what causes the problem has proven surprisingly difficult.

Apollo astronaut Ronald Evans performs an extravehicular activity in 1972. (NASA)

In 2010, a team of researchers studied 232 hand injuries reported by astronauts and found a significant correlation between the width and circumference of astronauts’ metacarpophalangeal joints — the joints at the top of the fist, where the palm and fingers meet — and their impact. Risk of injury.

Their study indicated that spacesuit gloves limit the movement of these joints, which increases stress on the fingers, leading to decreased blood flow, tissue damage, and onycholysis.

Space suit gloves are actually rather complicated. They are made of at least four layers: the comfort layer, which is in direct contact with the skin; the pressure bladder layer, which inflates and hardens when pressure is applied to the glove; A restrictive layer to counter the stiffness of the pressure bladder, to allow movement; The outer layer of microthermal clothing is the outer skin of a spacesuit that protects the wearer from space inside. This outer layer consists of several layers, each of which is separate.

Astronaut Oleg Kotov performs extravehicular activity in 2013. (NASA)

To try to narrow down the risk factors associated with onycholysis, a team led by engineer Christopher Reed, formerly of Lockheed Martin and now at Boeing, studied onycholysis injuries in astronauts. Their study, published earlier this year, looked at 31 onycholysis injuries — 27 during training, and four during extravehicular activity — reported by 22 astronauts.

They found that the design of the glove played a very important role. Of the two types of gloves in their study, one was associated with 8.5 times the risk of fingernail loss. Most injuries occurred in the middle finger. Glove size and middle finger length also played a role. Onycholysis appears to be more likely in women than in men.

Overall, the results seem to suggest that poor glove fit may play a role. Although, for NASA astronauts at least, the gloves are personally fitted to each wearer. But a solution may finally be on the horizon, with new Artemis-era spacesuits on the horizon.

So that’s one less thing to worry about. Now someone needs to know what to do if you need to burp. Astronauts certainly have to be dedicated to their jobs.

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