How Do Astronauts Sleep in Space?

“Byeoli, what’s that? Why is the bed attached to the wall?”

“It’s the sleeping bag astronauts use to sleep on a space station. There’s almost no gravity here, so if you just lay down, your body would drift and bump into walls or equipment. So the sleeping bag gets strapped firmly to a wall or floor, and you climb in and zip it up.”

“So there’s no need for a blanket?”

“Right. A blanket would just float away too, so it wouldn’t help. The sleeping bag itself wraps around your body instead.”

Hyeongseop climbed inside one to try it. His arms and legs felt gently pressed, and strangely, it felt comfortable.

“What about your arms? Wouldn’t they just float around?”

“Exactly. Some astronauts tuck their arms inside the bag, while others just let them float freely. At first, some people find it hard to fall asleep with their arms drifting, but everyone adjusts eventually.”

“But the station sees the sun rise and set outside the window all the time. How do you even know if it’s day or night?”

“Good question. The station actually sees the sun rise and set sixteen times a day. So they cover the windows with shades, and their body clocks just follow Earth’s regular daily schedule. Lights turn off and on at set times to artificially create day and night.”

“That still sounds hard to sleep through.”

“People really do struggle to sleep at first when they go to space. But here’s something interesting too. Without gravity, nothing presses your body in any direction, so some astronauts actually say they sleep more comfortably than on Earth.”

“Is that because their back doesn’t get sore?”

“Exactly. On Earth, even the best mattress still has your body weight pressing into your back. In space, there’s no such pressure at all, so your body naturally floats into the most comfortable position on its own.”

“How many hours do astronauts usually sleep?”

“Their schedule usually allows about eight hours. But when experiments or observations get busy, some nights they get less. So mission control carefully manages their schedule to make sure they get enough rest.”

Hyeongseop curled up inside the sleeping bag. Floating there, fixed to the wall, felt strangely as cozy as being held in someone’s arms. On Earth, sleeping pressed into a mattress had always seemed obvious, but sleeping without anything pressing down on him felt, somehow, even more free.