How Do Astronauts Sleep in Space?

Fred Haise didn’t sleep much on his ill-fated Apollo lunar journey.

Haise was to be the sixth astronaut to walk on the moon when he launched into space on the Apollo 13 lunar module in 1970. But almost 56 hours into the flight, both oxygen tanks blew and the spacecraft lost electricity, light and water.

When the electrical systems failed, the craft lost its heat source and the temperature plummeted to 38 degrees. Sleep was nearly impossible because of the extreme cold.

“Following the explosion, we got cat naps in,” says Haise. “I just hung my arm around one of the space suit attachment cables in the lunar module to keep me in position while sleeping.”

Today, Haise lives in Houston and serves on the board of directors for the INFINITY Science Center, a nonprofit museum located on the Mississippi Gulf Coast that serves as the official visitor center for NASA’s Stennis Space Center.

Of course, not every mission is as drama-filled as Apollo 13 (or becomes the subject of a Hollywood movie), and many space scientists do get sleep – a little.

“One has a lot of leftover excitement from the launch, heading out to the moon with spectacular views, to sleep deeply the first night,” says Haise.

Videos of astronauts rolling around in space abound. Microgravity keeps them floating like particles of dust blown off a bookshelf. So, how can they possibly get the sleep they need up there? It’s tricky.

Although weightlessness allows sleep in any position – even on the ceiling – astronauts mostly tether themselves to sleeping bags to prevent floating around and bumping things as they sleep.

Space Sleep Challenges

Since there’s a new dawn every 90 minutes in space, astronauts wear blackout eye masks to keep the light at bay. Strange noises, like whirring fans and 24-hour-humming equipment, call for ear plugs. Then there’s the feeling of floating or motion sickness coupled with sketchy temperature control, which all can make sleep elusive.

Astronauts typically sleep in canvas sleeping bags tethered to the wall in their living quarters, according to NASA. Haise says the zero gravity sensation doesn’t really affect sleep quality, though it feels weird not having a bed pressing against your body’s pressure points – it’s a bit like letting your limbs relax while floating in a pool.

With no bed pressing against their bodies, astronauts can wake up from free-floating sleep feeling disoriented and with a missing limb sensation (the pain-like phantom feeling some amputees experience). This doesn’t happen if you’re strapped snugly in your sleeping bag, according to IFLScience.

“There are some interesting effects on body position when an astronaut sleeps in space. The limbs find a comfortable balance between stretched and flexed,” former astronaut Story Musgrave, who flew six space shuttle flights, told IFLScience.

Space Wake-ups

Waking up is also different in orbit. Sunrise in space isn’t a gradual exposure to light. One minute it’s pitch black and the next, someone has turned on a lightbulb the size of the galaxy.

With all those sleep distractions, it’s easy to see why astronaut insomnia has been a prevalent problem, according to The Lancet Neurology journal.

While in space, NASA scheduled astronauts for a full eight hours of sleep at the end of their workdays, though many stayed up late looking at the stars, or woke up in the night and couldn’t get back to sleep. In fact, NASA reports that many astronauts took sleeping pills.

The space agency even worked on a light bulb that produced melatonin, the sleep hormone, but astronauts still averaged between 30 to 60 minutes less sleep each night than they got at home on Earth, according to Scientific American.

The Apollo 13 spacecraft has long since passed into history, and the shuttle program was ended in 2011. But just last year, astronaut Scott Kelly spent 340 consecutive days on the International Space Station. Hopefully he learned to sleep well.