Sleeping in Space: Coping with Darkness & Light6 min read

Getting a good night’s sleep on Earth is hard enough as it is — but to get 8 hours of shut-eye in space is another challenge altogether. You definitely won’t be in Kansas anymore once you break the earth’s atmosphere. With predictable 24-hour days far behind you, rest may seem like an impossible dream to astronauts.

Sleep is essential to keep us healthy. In fact, the combined benefits of exercising, vitamins, and washing your hands don’t even come close to what sleep can do for your health. However, that doesn’t mean astronauts can’t enjoy these same health rewards as well. Even though night and day doesn’t work the same in space as it does on earth, there are ways to get around this and make space more bedtime friendly.

Astronaut Paolo Nespoli sleeps during a 2007 mission on board the ISS. NASA

How Do Astronauts Sleep in Space?

Many things are different between the lives of an astronaut and an earth dweller, but nothing quite separates the two like the bedtime routines of men and women in space. Since there is microgravity on the International Space Station (ISS), all sense of direction is lost, meaning astronauts can sleep pretty much wherever they want, including the ceiling.

Sleeping bags serve as the beds for astronauts, so the biggest thing they have to worry about is tethering it — and themselves — down so they’re don’t float around and bump into things when trying to sleep. Each astronaut also has their own cabin to call their own, or an ISS module if there aren’t enough cabins to go around. These quarters are soundproof to make sleep as easy as possible for everyone on board.

Despite no noise being able to escape, their rooms are well ventilated to make sure they have a steady stream of oxygen available to combat the potentially suffocating carbon dioxide the astronauts produce themselves. Unlike on earth, astronauts are able to witness 16 sunsets and sunrises give or take every day. The thought of seeing so many sunrises and sunsets may sound like something that shouldn’t be missed, but you’ll soon learn how one can get tired of this fairly quickly.

The Importance of Light Control in Space

Our bodies are in tune to the light and darkness that they’re exposed to. Too much or too little of one or the other can cause some major havoc on your internal body clock. This is because earthlings are used to a 24-hour sleeping and waking cycle called a circadian rhythm.

Our circadian rhythm is influenced by many factors, including temperature, light exposure, and body position among other things. These components are predictable and can be regulated easily when you’re on Earth. However, when you’re up in space, these things become much harder to control.

One of the biggest issues is the absence of 24-hour days in outer space. After all, light and darkness are our bodies’ signals when it’s time to get up or go to sleep. Although you may be aware that 24 hours have passed while in space, your body does not since those cues are saying something else.

Light and the absence of it is what decreases or increases the amount of melatonin our bodies produce respectively. Melatonin is a hormone that helps us go to sleep by lowering our body temperature, blood pressure, and glucose levels — each an essential ingredient for a good night’s rest.

Too much light will hinder this hormone’s production and leave us wide awake. This is because light triggers our brain to become alert, increasing our body temperature and producing hormones like cortisol to shake us from sleep. Ultimately, this disrupts our circadian rhythm and makes sleep feel like a distant memory. One of the closest things we have on Earth that has similar effects on our sleep is daylight savings time.

How to Get Deep Sleep in Deep Space

There might not be a lot of things you can control in space, but one thing astronauts have some power over is the quality and amount of sleep they can get. First, knowing what helps you fall asleep or wake up is crucial to a healthy sleep schedule no matter if you’re in space or not.

Since astronauts experience multiple sunrises and sunsets a day, it’s important that a strict sleep schedule is kept to combat this. By planning appropriate activities around waking and sleeping times, astronauts can maintain the circadian rhythm and health they enjoyed on earth. Being an astronaut is a job just like any other career, and having a good work-life balance is pertinent to make sure their daily needs are met.

In order to meet these needs, astronauts have to put in the time to sleep train while also taking care of their other responsibilities. You may not think you need to train your body to sleep, but in space, it’s a whole different ball game. One way astronauts do this is through the use of artificial LED lights. These lights let your body know it’s “day time,” naturally waking you up. This is similar to the use of light therapy for individuals who experience Seasonal Affective Disorder during the bleak winter months when sunshine is at its lowest.

On the other hand, when it’s time for bed, it’s recommended to cover up any nearby windows to reduce the amount of light or heat you’re exposed to. It’s imperative to have complete darkness when you fall asleep — with some astronauts opting to wear sleeping masks as well to block out even more light. Supplements and diet are a part of a healthy sleep schedule for astronauts as well.

When there’s not enough darkness to be had to put you in a sleepy state, astronauts can ingest melatonin supplements to help them get there. If you have the opposite problem and can’t stay awake, caffeinated products are there to the rescue. Lastly, staying away from lights and electronics before bedtime can help astronauts catch those elusive Zs no matter what planet they’re on.

It may seem like rocket science to get a better night’s sleep in space — and although some science is involved, astronauts can hit the hay no problem by following a few tips. By choosing how much light and darkness they’re exposed to, astronauts can set up a sleeping environment that is more conducive to slumber success. Even though there’s no such thing as a normal Earth day in space, there are things astronauts can do to maintain their circadian rhythm as well as their bedtime.


Avery Phillips is a freelance human based out of the beautiful Treasure Valley. She loves all things nature, especially humans, and was driven to pursue an Anthropology degree due to her childhood love of Indiana Jones and Laura Croft. Now she lovingly writes about all things great and small.

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