Female astronaut in zero gravity sitting in cockpit of space shuttle

The Conversation

1. Astronauts have to sleep through multiple sunrises each “night”

While your internal clock may get screwed up when traveling or changing the clocks for Daylight Saving’s, astronauts are always jet lagged. The International Space Station orbits around the Earth, giving astronauts a sunrise and sunset every hour and a half. Essentially, they have to sleep through multiple sunrises for one “night’s” rest.

Astronaut sleeping space stationAstronaut sleeping space station

While gravity is pulling the space station in circles around Earth, the astronauts inside feel “microgravity” which is very nearly zero gravity. To not float away while sleeping, astronauts zip themselves into sleeping bags and then strap themselves down. They also use eye masks to block any light and a set sleep schedule for when they wake up and go to bed, or rather, strap into their sleeping bags.

2. In space, you don’t know if you have to pee or not

Zero gravity affects human bodies in a myriad of ways, from decreasing muscle mass to weakening bones, but it also makes it nearly impossible to tell when you have to pee. The pressure on your bladder that normally alerts you isn’t there, so it’s hard to tell when you gotta go. During takeoff, landings, and spacewalks, astronauts wear adult diapers.

International Space Station toilet bathroomInternational Space Station toilet bathroom

However, while on the International Space Station, astronauts use the specially designed bathroom. It suctions up the waste; the pee gets turned into drinking water (yes, for real), and the solid waste is put on a spacecraft that burns up in the Earth’s atmosphere. Astronauts actually have to train on Earth with a strategically placed camera to use the “toilet” since the opening is rather small.

3. If you try to burp in space, you’ll throw up

Just like an astronaut floats in the space station, the contents of their stomach float, too. Normally, on Earth, the gas in your stomach can come back out in a burp because it’s lighter than the liquids and solids. However, in space, all that stuff is mixed together in globs in your stomach.

NASA astronauts International Space StationNASA astronauts International Space Station

If you try to burp while in zero gravity, more than just air will come out. To deal with this, one NASA astronaut made up the “push and burp” technique to deal with this issue. He pushes off a wall while burping to make the gas go one way and the food to go the other.

4. After exercising, astronauts are covered in sweat balls

While in space, astronauts have to exercise at least two hours a day because they don’t use their muscles enough while floating around. Plus, their bones can’t reabsorb calcium and so they lose bone density faster than a person with osteoporosis. But while exercising, astronauts still sweat.

Astronaut working out treadmill sweat spaceAstronaut working out treadmill sweat space

Sweating in space is not like sweating on Earth. In zero gravity, sweat doesn’t drip off your skin, it sticks to you and clumps up in little balls. You could float around with these sweat blobs on your body, but astronauts towel it off and collect it. Just like their urine, the sweat is filtered and turned into drinking water.

5. In space, tears cover your eyes in stinging blobs

Astronauts better not get too homesick in space because crying is pretty uncomfortable. On one spacewalk, astronaut Andrew Feustel got a flake of anti-fogging solution in his eye. Of course, anyone on Earth could just wipe it out, but Feustel’s head was enclosed in his helmet, unreachable.

Astronaut water bubble floating space zero gravityAstronaut water bubble floating space zero gravity

In space, tears don’t roll down your face. They stay in blobs around your eye and sting painfully. On the space station, you can wipe them away or wait until the blob gets big enough to float away. During the spacewalk, Feustel had to awkwardly rub his eye on something in his helmet. It was inconvenient and irritating, but luckily not life-threatening.

6. Astronauts lose their sense of smell and love Tabasco sauce

On Earth, your bodily fluids are governed by the laws of gravity and so they generally move down your body. In space, however, everything is out of whack. Your fluids are all over the place, so things like mucus clog up your head, giving you symptoms of a cold.

Astronauts eating meal space zero gravityAstronauts eating meal space zero gravity

So while your face is puffing up, your nose is stuffed up. Thus, astronauts have a weaker sense of smell than they normally would planet-side. As a result, their taste in food often changes. Most astronauts really like spicy space foods, like Tabasco sauce and hot peppers. Perhaps they just want to be able to taste anything.

7. Astronauts see “luminous dancing fairies” when they close their eyes

Astronauts often have PhDs in highly scientific fields, so they’d probably be the last people to say there are fairies in space. And yet, that’s what astronauts have been talking about ever since they first landed back on Earth. When they close their eyes, lights dance in the darkness of their eyelids.

Astronaut international space station livingAstronaut international space station living

As mysterious as these lights are, scientists have at least one hypothesis about what causes them (no, it’s not fairies). They think cosmic rays, aka energetic particles speeding through space, pass through the astronauts’ eyelids and hit the photoreceptors in their pupils. These photoreceptors communicate with our brains to form a picture, which makes up what we see.

8. Astronauts launch their dirty laundry to a fiery death

In between astronauts’ fancy orange blast off suits and their incredibly heavy, life-supporting space suits, astronauts have to wear clothes just like anyone on Earth. However, while the International Space Station has millions of dollars worth of advanced technology, it does not have a washer or dryer. So what do astronauts do with their dirty clothes?

Astronauts work in international space stationAstronauts work in international space station

They burn them. Astronauts pack their dirty clothes in bags, after perhaps weeks or months of wearing them, and then put them on a spacecraft headed for a suicide mission. The spacecraft is sent flying to Earth’s atmosphere where it burns up upon reentry. Scientists on Earth are working on fabricating materials that won’t get so dirty and will be easier to clean.

9. Astronauts have liquid salt and pepper

Imagine you’re about to eat mashed potatoes and you sprinkle some salt on them, but the salt just floats away before it can ever reach your food. That’s what salt shakers in space would be like. Oh, and then the salt particles might clog the air vents, damage the expensive equipment, or float right into someone’s eye.

Liquid salt and pepper spaceLiquid salt and pepper space

So when astronauts aren’t using Tabasco sauce, what do they season their food with? They have bottles of liquid salt and pepper because liquids are easier to control than powders. Liquids form spheres in zero gravity because a sphere has the least amount of surface area. Plus, water is attracted to water (with or without gravity) and it likes to stick to things because of its chemical properties.

10. Velcro is everywhere on the International Space Station

Like a little kid who can’t tie his shoes, astronauts love velcro. Back during the Apollo missions, some astronauts put a piece of velcro in their helmets to scratch their face on whenever they got an itch. Now, astronauts have a Valsalva device in their helmets, which they primarily use to clear their ears of pressure, but it works well enough for nose scratching.

Astronaut scott kelly space velcroAstronaut scott kelly space velcro

Around the International Space Station, most things have velcro attached to them. That way, the toothpaste tube or towel or whatever can be easily attached to a strip on the wall rather than float around the station all day. Astronauts themselves can have velcro strips on their pants that effectively act as pockets.

11. Bread is not allowed in space

During the Gemini 3 mission in 1965, two astronauts smuggled a corned beef sandwich onto the spacecraft. They ate it together as crumbs floated everywhere and wreaked havoc. Fortunately, the crumbs didn’t do much more than irritate their eyes, but they could have started a fire in the electrical panels.

Tortilla space station zero gravityTortilla space station zero gravity

Since then, bread has been banned from space. So astronauts said, “hello tortillas” and haven’t looked back. Some food scientists on Earth are working on making crumb-free bread and space ovens that people could bake with. One idea is to make an oven that is low pressure on the inside, like a vacuum, which would actually make bread rolls fluffier.

12. Astronauts don’t actually eat freeze-dried ice cream

Perhaps you visited a science museum once and got a package of “space ice cream.” You probably ate it happily, thinking about how lucky you are to be able to eat real ice cream because this stuff sucks. How do astronauts live off of this, you might have thought. Apparently going into space is worth it?

Astronaut ice cream freeze dried spaceAstronaut ice cream freeze dried space
Ruth Hartnup/Wikimedia Commons

Well, it turns out astronauts don’t even eat it. The “ice cream” never made it to space, which is probably for the best since it’s pretty crumbly. But space would be the perfect place to enjoy an ice cream cone because you could never experience the horror of dropping it on the sidewalk. If the ice cream comes off the cone, it’ll just float around until you scoop it back up.

13. You can’t drink alcohol in space

While astronauts may want to unwind after an 8-hour spacewalk with a beer, it isn’t allowed on the International Space Station. First off, NASA doesn’t want astronauts getting drunk because they wouldn’t be able to deal with a life or death emergency. Secondly, carbonated beverages, in general, are banned because of how zero gravity impacts the bubbles.

Astronaut coffee space stationAstronaut coffee space station

On Earth, the carbon dioxide bubbles float to the top of the beverage. In zero gravity, they would be randomly distributed throughout the drink and make a frothy mess. Plus, the gas bubbles would make the astronaut need to burp and we already learned about how uncomfortable that is in space.

14. Astronauts actually eat some fresh foods

While most space food is freeze-dried or thermostabilized to ensure it is edible for at least two years, astronauts sometimes get fresh fruit and vegetables sent to them. These only last a couple of days with no refrigerator and thus need to be eaten right away, but they provide a nice reprieve from the packaged foods.

Astronauts floating fruit space zero gravityAstronauts floating fruit space zero gravity

They get things like oranges and apples, which are real treats on the space station. Perhaps one day astronauts (and other space explorers?) will be able to eat more fresh foods and even enjoy a refrigerator, but we aren’t quite there yet. However, scientists are working on 3D printing food items in space.

15. When first getting to space, astronauts have to suffer through space sickness

While going to space is exhilarating, the first few days can be rather uncomfortable. There is no up and down because there’s no gravity pulling on the little sensory hairs in your ears. The result is disorienting, discomforting, and nauseating. The human body is just not ready for such a change.

Astronauts space station floating zero gravityAstronauts space station floating zero gravity

Astronauts also get headaches and vomit from the experience. The feeling is called space sickness or Space Adaptation Syndrome. Only about half of all astronauts get space sickness when they first go into space. It isn’t caused by weightlessness exactly, but by the change in gravitational force pulling on the astronauts.

16. Space suits keep astronauts from literally boiling

Whenever astronauts go on a spacewalk, aka exit their spacecraft to float around in the emptiness of space, they must wear a space suit. When orbiting Earth, space can be as hot as 250 degrees Fahrenheit in the sunlight and then as cold as negative 250 degrees.

Astronaut spacewalk space extravehicular activityAstronaut spacewalk space extravehicular activity

In space, you don’t even have to get angry for your blood to boil. The low pressure in space, caused by the vacuum and lack of particles, reduces the boiling point of water. Thus, if you were out in space without a suit on, your blood (and eyeballs) would boil. How metal is that? Astronauts wear fancy suits to keep this from happening to them.

17. The first astronauts used a creative method to get life insurance

With the prospect of blood boiling on the mind, the Apollo astronauts (those on the Moon missions) wanted life insurance. They were about to go where no human had gone before, leaving their families behind on Earth. The astronauts wanted some sort of assurance that their families would be okay if the worst were to happen.

Astronaut apollo insurance card autograph signed coverAstronaut apollo insurance card autograph signed cover

But life insurance policies were too expensive for someone about to go to the Moon, so they got creative. The three astronauts signed hundreds of postcards and gave them to a friend who got them postmarked on important days (like their launch and moon landing). The friend gave these to the astronauts’ families who could sell the autographs for money, despite it being long before eBay.

18. Astronauts have to file travel request papers to go to space

The worst part about traveling abroad is having to go through customs, sign forms, and declare this or that. Even space travel requires you to fill out travel authorization requests. Buzz Aldrin (y’know, the second guy to walk on the Moon) filed a travel expense form and was reimbursed $33.31 for his business trip to the Moon and then back down to the Pacific Ocean.

Apollo customs form paperwork space moonApollo customs form paperwork space moon

There were even customs forms for the Apollo 11 mission declaring the moon rocks and moon dust samples the astronauts brought back. However, since they were pretty important guys, the three astronauts didn’t sign the forms themselves (they had done enough signing for their life insurance). The flight number? Apollo 11. Departure from where? Moon.

19. Some astronauts randomly drop things when back on Earth

After spending days, weeks, or months in space, coming back to Earth and all its gravity can be a difficult transition. Astronaut Scott Kelly had trouble walking properly after landing back on Earth. His legs were swollen and sore from all the fluids flowing back into them. Plus, he had hardly used them in about a year.

Astronaut scott kelly landing on earthAstronaut scott kelly landing on earth

Astronauts also tend to briefly forget they’re back in the throes of gravity: they randomly drop things, their subconscious expects the item to float in place rather than crash to the floor. Shortly after landing back on Earth, astronaut Joe Edwards was handed a cup of lemonade and asked to take off his shoes. He promptly dropped the cup while reaching for his shoes.

20. Becoming a NASA astronaut is far harder than getting into Stanford or Harvard

After reading all the weird and uncomfortable things astronauts have to deal with on a daily basis, do you still want to be one? Well, good luck. NASA has a far lower acceptance rate to their astronaut training program than Stanford University (the most selective university in the United States). Stanford’s is around 4.3%, while NASA’s is about 0.065%.

Astronaut candidates class NASAAstronaut candidates class NASA

The crazy part is that after this handful of people are selected, they have to train for two years as Astronaut Candidates before NASA decides if they will actually go to space. But to even get your foot in the door, you’ll need at least a bachelor’s degree in engineering, science, or math. Then you’ll need either three years of professional experience or 1,000 piloting hours.

21. Astronauts train with a giant air hockey table

After becoming an Astronaut Candidate, you have to go through a slew of training exercises and classes. In space, there is little room for error, so astronauts must be fully prepared to operate space machinery, move around in heavy suits, and anything else they can expect to face (like using the bathroom).

Astronaut spacewalk spaceAstronaut spacewalk space

So how does the air hockey come into it? Well, astronauts might need to move huge objects in space. Zero gravity makes the objects easy to push around, but difficult to stop. So astronauts practice moving things on the Precision Air-Bearing Floor, which is essentially a giant air hockey table.

22. To get used to zero-G, astronauts take a ride on the Vomit Comet

Alright so you’ve had your fun playing massive air hockey, but now you’ve got to go for a ride on the Vomit Comet. Sound fun? It’s a specialized aircraft that flies up and down to simulate zero gravity for about 20 seconds at a time. But since the flight is full of sudden switches between weightlessness and “oh yeah, gravity,” it’s a stomach churner.

Astronauts vomit comet planeAstronauts vomit comet plane
NASA on the Commons/Flickr

The astronauts endure up to 40 of these weightless moments in one day’s session. Even experienced astronauts get sick on the Vomit Comet, which is officially called the KC-135. While filming “Apollo 13,” Tom Hanks and Kevin Bacon had to go for their own ride in the aircraft, acting for just 30 seconds at a time.

23. Astronauts must swim laps while wearing 280-pounds of spacesuit

When the Astronaut Candidates aren’t high up in the air doing stomach dropping training, they’re working deep in the Neutral Buoyancy Laboratory, which is basically a giant swimming pool. In the 40-foot deep pool, astronauts practice extravehicular activities (a fancy term for spacewalks).

Astronauts underwater training space suitsAstronauts underwater training space suits

The water simulates a zero-gravity-like environment for the astronauts to get used to moving around with their giant spacesuits on. Each suit weighs about 280 pounds and takes 45 minutes to put on. While training, astronauts must prove that they can swim three lengths of the pool with the suit on. In space, the suits weigh nothing.

24. All astronauts must learn Russian

Astronaut training isn’t all math, science, and physically demanding exercises; they have to learn Russian, too. But it’s no easy task. For British astronaut Tim Peake, learning Russian was the hardest part of his training. He must have had an iron stomach.

Astronaut and cosmonautAstronaut and cosmonaut
NASA on The Commons/Flickr

To get a ride to the International Space Station, you’ve gotta go on Russia’s Soyuz spacecraft, whose controls are exclusively in Russian. While the Soviet Union and the United States competed for years in the space race, it “officially” ended in 1975. About ten years later, Russia, the U.S., and several other countries began collaborating on the International Space Station.