Some astronauts report losing their fingernails on spacewalks because of bulky gloves that cut off circulation and chafe against their hands. To avoid this inconvenience, a couple astronauts have taken to ripping off their own fingernails before reaching orbit.
Fingernail trauma and other hand injuries are spacewalkers’ biggest complaint, she said. 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.