Astronauts are, by necessity if not always by nature, a tidy bunch. When you watch them doing their thing on the International Space Station, they're almost always clean-cut and clean-shaven. This is true even of Chris Hadfield -- an erstwhile space traveler who, though famously mustachioed, was always reliably smooth of skin.
In the video above, Hadfield explains how he consistently achieved his clean-shaven look -- with the help of basic razors, Velcro-able cloths, and, maybe most importantly, a special version of space-tailored shaving cream. Hadfield needed that last product because shaved-off whiskers, if left to float around in the ISS's air, would not only be disgusting and dangerous to breathe; they could also clog up the delicate filtration systems on the Station, leading to infrastructural problems that would be, all too literally, hairy.
Enter AstroEdge, astronauts' shaving cream of choice. The stuff is slick enough to allow a razor to do its thing without water ... but sticky enough to trap shaved-off stubble so that it's not free to float around. To use it, Hadfield explains, you rub it on and do your shaving. After each swipe of the razor, you wipe away the cream to prevent errant stubble from floating away. Pretty much like what you'd do on Earth, minus the water and plus THE SPACE.
For haircuts, in case you were wondering, astronauts have a different method -- this one involving an electric razor and a vacuum-like machine that sucks the cut hairs away. (Editor's note: please insert Wayne's World "SuckCut" reference.) Astronauts cut each others' hair using the machine. It is sort of terrifying.
And, finally -- most importantly -- what about the mustache? Where does that fall on astronauts' beard-hair-to-hair-hair continuum? "The mustache requires a little extra attention," Hadfield jokes of his famous facial festoon. "You have to," yep, "use a vacuum."