In a recent study of astronaut injuries, at least 22 reported lost fingernails, a phenomenon called fingernail delamination. It happens because of pressure on the fingertips, but researchers also think circulation cutoff could be to blame, NGN explains.
Astronaut gloves are designed to simulate the air pressure on Earth, so they’re made of a pressurized rubber layer embedded in a thick, space-proof shell. Spacewalking astronauts must constantly fight against the bulky pressurized glove to do their work — imagine gripping a wrench while wearing skiing mittens, and you get the idea. This constant bending and flexing causes chafing, blisters and, apparently, fingernail loss.
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