How Astronauts Sleep

This content was created by the National Sleep Foundation


Can’t sleep? Try dozing off in zero gravity!

Think you have trouble getting enough sleep? Imagine that when you said goodnight, you could expect the sun to set—and then come up again—about five times during your eight-hour “night.” Now consider lying down when there’s no, well, down—due to zero gravity. That’s the daily reality for astronauts living and sleeping in space. But they still manage to get their shut-eye! Learn how...

They Get Primed for Takeoff. Beginning three to seven days before takeoff, astronauts are exposed to bright light at certain times throughout the day in order to manipulate their biological clocks to be wide awake at the time of the launch.

They Manufacture a 24-Hour Day. The truth is, without the sunrise and sunset to tell you what time it is, your body defaults to a 24.2-hour day. That’s why while they’re in orbit, circling the Earth every 90 minutes, astronauts are largely dependent on bright fluorescent lights to set—and re-set—their biological clocks.

They Exercise—A Lot. There isn’t muchfree time in space. But physical activity is part of the itinerary in order to counteract the bone and muscle loss that comes with living in space. On the International Space Station, astronauts’ schedules typically include about two hours of exercise a day.

They Sometimes Sleep Standing Up. Chances are, you take it for granted that when you lie down you feel something underneath you. For space travelers, there’s no such luxury, so they often sleep standing up. 

They Strap Down Anything They Don’t Want to Float Up. To mimic the feeling of sleeping on Earth, many astronauts sleep in sleeping bags that are tethered to the floor or wall. They also might sleep strapped into a seat. But remember—even free arms need to be strapped down to avoid their hovering while the space traveler is asleep.

They Block Out Light. Sleep masks are a must for blocking out light when dawn happens every hour and a half in orbit. They also cover up windows and steer clear of the bright, hot cockpit.

They’re Constantly Learning. If drowsy driving in an automobile is dangerous, then you can only imagine how important it is that astronauts be well rested. Still, astronauts average two hours less sleep than they do at home, and more than 75 percent of astronauts report using sleeping pills. That’s why NASA is constantly researching ways to improve their sleep, such as having astronauts at home and in space wear watches that track their sleep patterns.