Warning: if you are looking for a story about the romance of space travel -- the adventure, the wonder, the transcendence of what we know in the name of exploring a great unknown-- this is not that. Turn away now.
Still with me? Great. Then here's something from the other side of space. The less romantic, and in fact vaguely disgusting, side. The side that involves drinking recycled urine and using bathrooms that involve vacuums and hair clippers that resemble medieval torture devices. This one involves ... skin. Skin which, in the normal course of things, sheds.
On Earth, we barely notice that process: our skin cells molt and and gravity pulls them away from our bodies, conveniently and invisibly. In space, however, there is no gravity to pull the dead cells (technically: the detritus) away. Which means that the detritus, left to its own devices, simply floats. Which, given the fact that multiple astronauts live on the Space Station at the same time, and the fact that even highly trained space travelers might get skeeved out by floating clouds of dead skin, is less than ideal.
In the video above, former ISS denizen Don Pettit describes what happens when, in particular, you take your socks off on the Station. "This cloud, this explosion of skin particles -- detritus -- floats out," he says. "And you're in this weightless environment, and the particles have nowhere to go but out." That's even true of foot calluses -- which, after a few months of weightlessness, tend to soften. I'll leave the details to Pettit, but the bottom line is this: if you ever find yourself living on a space station, make sure the station's ventilation system works really, really well. Because, as astronaut Mike Massimino sums it up in the video: "This sounds actually pretty disgusting."
"Well, it is," Pettit replies. "But it's part of being a human."
Via Chris Hadfield