You've seen how astronauts cry in space, but what about how they sleep?
Chris Hadfield, who currently lives on the International Space Station, explained how he catches some Zs in a zero-gravity environment.
All it requires is putting on a pair of "space jammies," then heading to your individual "sleep pod," which has a sleeping bag tied to the wall inside. Without gravity, there's no need for a pillow or mattress -- simply relax, and float.
What do you think of how astronauts sleep in space? Could you sleep in zero G? Tell us in the comments, below.