Floating in microgravity, gazing at multiple sunrises and sunsets every day, and being among just a handful of people who’ve explored the final frontier — going to space can sound pretty dreamy... that is, until you consider the special efforts required to get some shut-eye.
Anyone who’s struggled to fall asleep on an airplane — or anywhere besides their own bed — might know that it’s hard to sleep in strange places. But space is out-of-the-world strange.
To understand what it’s really like to sleep in space, we went straight to the source: the astronauts themselves. Here’s what they had to say about the challenges they encountered and the creative solutions they found.
How is sleeping in space more difficult?
First, an astronaut’s bedtime routine in space is quite different from the usual one on Earth. They have to tuck themselves into a full-body sleeping bag that has a cutout for the face. Then, because of the weightless atmosphere, they need to attach the sleeping bag to something stable — usually a wall inside the individual sleeping pod where they’ll spend the night.
NASA research shows that astronauts sleep just 6 hours per night, on average, even though most mission schedules include time for 8.5 hours of sleep. Sleeping in space can be as challenging as rocket science, for reasons such as these:
- Orbiting around the earth can throw off an astronaut’s circadian rhythm, making it more difficult to fall asleep at bedtime — hence why some of them rely on sleep meds while in space.
- The phone-booth-sized sleeping pods can feel cramped and noisy compared to a typical bedroom.
- The human body’s efforts to adapt to microgravity, which is very weak but not zero gravity, can cause temporary physical discomfort, such as spinal stretching. Long-term exposure could cause issues such as bone and muscle loss.
- While the International Space Station has special lighting to promote better slumber, it still bombards astronauts with noise from fans circulating air, and immerses them in an environment that’s about 72 degrees (warmer than the best temperature for sleep), leading to frequent sleep disturbances.
- The thrill of achieving the lifelong dream of reaching space can also keep many astronauts up during their scheduled sleep time, especially in the first few days, when the novelty still feels very fresh.
Yet while many astronauts say they struggled to get enough rest, others relish the time they spent catching Zzz’s in space, calling it the best sleep of their lives.
How astronauts sleep in a weightless environment and with microgravity
Sleeping in space was an “outstanding” experience for NASA astronaut Nicole Stott, who has flown two spaceflights and spent more than 100 days in space. There’s no up or down in microgravity, so astronauts can choose to sleep in any direction that’s comfortable.
“I always chose the ceiling to sleep on, because where else can you sleep on the ceiling?” says Stott. “It was so cool to tie your sleeping bag onto the overhead area and float into it, kind of like Dracula climbing up the wall.”
For safety purposes, an astronaut is often required to attach their sleeping bag to something. Otherwise, they’ll float around aimlessly until they wind up next to the air intake vent, adds Richard Garriott, America’s first second-generation astronaut, who tapped into the fortune he built developing video games to co-found Space Adventures, a space tourism company. He has spent 12 days in space since 2008.
But that’s certainly not the only way for a sleeping astronaut to stay in place.
“One of my crewmates who found it easy to sleep would relax into a fetal position and tie a shoelace to the floor and fall asleep,” says Garriott. “I’d look down the hall and see him dangling from a shoelace in the middle of a hallway.”
Not getting tucked in worked well for Stott, who says, “You’re essentially floating in a sleeping bag — there’s no pressure points, you’re not shifting, and there’s no load on your body.” But she admits there was an adjustment period, especially as the body changes in microgravity.
“The first couple of days of that first flight were a little difficult because when you get out of the gravity environment, your spine elongates and it causes lower back pain,” says Stott, author of the book “Back to Earth: What Life in Space Taught Me About Our Home Planet and Our Mission to Protect It.”
While she’d normally bend over and stretch to relieve lower back pain, that didn’t work in microgravity. Fortunately, the pain went away after a couple of nights.
Getting creative about comfort in space
Many astronauts, like Stott, have found the weightlessness to be incredibly soothing once their bodies and brains recalibrated to the lack of gravity.
“When you’re floating around 24 hours a day in space, you can just relax every muscle in your body and naturally take this floating fetal position where there’s literally no pressure on any joint, muscle, or bone,” explains Garriott.
But for Garriott, who also says he’s “the poster child for difficulties sleeping in space,” that weightless feeling was a challenge.
Garriott “appreciates a tucked-in feeling,” he explains. He had to devise a special system involving bungee cords to make it feel like he had the weight of a comforter atop his body. “I’d strap half a dozen gentle bungee cords around the sleeping bag to hold the surface against me, then I’d crawl inside of it to get that feeling I like,” he says. Additionally, his head would float off the pillow-like surfaces he tried to create.
Garriot also learned the hard way that his preferred face-down sleeping position wouldn’t fly in space. “The sleeping bag they provide you is mummy-shaped with a face hole, and I made the mistake of turning my face inside the sleeping bag,” says Garriott.
That meant fresh oxygenated air couldn’t circulate around his nose and mouth, leaving him breathing the same bubble of carbon dioxide-filled spent air he had exhaled all night long.
“I woke up with a terrible headache, probably due to the combination of a lack of oxygen and an overload of carbon dioxide in my sleep cycle,” says Garriott. “It took me a couple of days and enormous amounts of aspirin and such to get over that.”
Remembering how to sleep when you’re back on Earth takes time
Just as it can take a few days to learn how to live in microgravity, the same can be said for remembering the physics of life back on Earth. Astronauts have to get used to the feeling of gravity on their limbs and wait as their vestibular system (a sensory system in the inner ear that’s involved with balance and spatial orientation) readjusts.
That can produce some interesting side effects at bedtime, like forgetting you can’t float around and falling onto the floor when you get out of bed. For Stott, returning to gravity made her feel really heavy when trying to sleep, as if she was sinking into the mattress.
“When you close your eyes, you feel like you’re doing somersaults. It was like having the drunk spins,” says Garriott. “The rotation would stop as soon as I’d open my eyes, so I’d just burn the midnight oil until I was exhausted and I could fall asleep more easily.”
There’s also a psychological impact on sleep, including on astronauts’ dreams. “Up until the time I flew in space, I would have this dream at least once a week from childhood on where I’d be running and jumping and trying to fly. Sometimes I would fly and it would be so freeing and joyful in my dream,” Stott says. “There’d also be times when I wouldn’t be able to fly, and I’d be frustrated in those dreams.”
But from the moment she visited space, she stopped having the recurring dream. She suspects that now that her body knows what it’s like to float and move in three dimensions, she doesn’t have to struggle with finding that feeling in her dreams anymore.
“Zero-gravity dreams inundated my consciousness for the next few months,” says Garriott. And that weightless feeling hovered over him, even when he wasn’t dreaming.
Returning back to Earth also brings the nuisances of Earth sleep. For Stott, waking up frequently and tossing and turning throughout the night are the norm for her. But she still loves sharing stories about her time snuggled up in her space compartment, where the “temperature is great, the airflow’s good, and it’s super dark.”
“People want to make a connection to space, and sleep is this human, relatable thing,” she says. “When you ask astronauts about sleeping, you’ll get different answers from different people — just like you do down here.”
