Before he returned to Earth on the Space Shuttle for the last time, Andrew Feustel got something stuck in his eye. On earth, a couple tears would have solved the problem—unlike Chuck Norris, astronauts can apparently shed tears—but the thing is, in zero gravity, the tears “don’t fall off of your eye . . . they kind of stay there.” Which makes sense, again, because there’s no gravity.The story got shared around a fair bit, because, most of us probably hadn’t thought about the difficulties of weeping at the sheer beauty of the cosmos. But it got us thinking about what else you might not be able to do in space.This breaks down into two categories, just as it would on Earth: there are things you physically can’t do, and then there are things you’re not allowed to do.Read the rest at Motherboard.