9 Totally Normal Things You Can’t Do In Space the Way You Do them on Earth

June 29, 2020

by Marco Giuliani and Ariel Tokarz

It’s not easy being an astronaut. 

Let’s talk today about some things you can’t do in space and answer some… intriguing astronauts-related questions, bust some myths, and clear some things. We will focus on sleeping in space – one of the most crucial issues to consider – but also eating, exercising, and even having sex in space.

Not only is it very hard to actually become an astronaut – essentially, you need to meet the criteria of a Renaissance man and then some, but the job comes with tons of responsibilities.

However, apart from maintaining a vessel that’s rocketing through relatively uncharted space, which is stressful enough on its own, even everyday tasks, such as washing your hands, need special in-space protocol. Since NASA is planning its Artemis mission on the moon and further research on Mars, we need all to remember that an astronaut in space has a pretty hard life, although nobody is complaining.

Here’s a short list of basic activities that are so hard to pull off in space that the brightest minds on earth had to gather and figure them out.

1. Cry – There’s (Technically) No Crying in Space

‘’In space, nobody can hear you scream’’ is perhaps one of the most quoted and parodied slogans in film history. While it worked in the context of the movie it was promoting, ‘’in space, you can’t cry, because it’ll be really inconvenient for you’’ would’ve been more honest and accurate.

If you are ever overcome with the weepies, there is no way to hide it. Take the case of astronaut Andrew Feustel who, after several hours of running power cables, realized that his helmet had begun to flake. One of those flakes ended up right in his eye, which caused it to sting ‘’like crazy’’.

In fact, according to Canadian astronaut Col. Chris Hadfield when asked about crying in space, the tears themselves can sting a bit.

Sure, astronauts can physically tear up. The only problem is that tears in space can’t flow downward in the way they do on earth, because there’s no gravity to pull them.

Instead, they stay on the eye. The more liquid accumulates, the more the astronaut cries, with tears even spreading to cover the entire eyeball. If the sphere of tears gets big enough, astronaut Ron Parise notes, it can even break free and float around the cabin. In other words, an astronaut in space who cries makes a mess and does not even release the sadness, as frustration probably replaces it with a vengeance.

So, if you’re ever in space, make sure not to think about those returning soldiers being greeted by their dogs’ videos that you used to binge late at night.

things you cant do in space crying

2. Use the Restroom Like Everybody Else – Normal Rules Must Be Adapted

Believe it or not, before going into space, all astronauts go through a state-sponsored potty training program. While it might be easy to laugh it off as yet another space-related quirk, this is actually a pretty important phase of the training.

If you remember our piece on fun yet strange facts about poop, you know that before heading into space, astronauts have to essentially ‘’reset’’ their toilet habits. It occurs because, as it turns out, doing a number two is a bit different than doing it on earth. There are two different mechanisms in your typical space station, each designed for a specific bodily function.

So, can you poop in space? Yes.

How do you poop in space? Well, now, this is a different story, so read on, as things get interesting when it comes to things you can’t do in space the way you do them on Earth.

How Do Astronauts Poop?

One of the hottest topics people debate is how do astronauts poop. Meaning how do astronauts poop in space, not back home, just to make things clear. Well, it is time to shine some light on this mystery once and for all:

  • When nature calls, astronauts either use a toilet seat purpose-built for solid waste and a vacuum tube for liquid waste, designed both for men and women.

In other words, to clearly answer the mind-bending questions of how do astronauts poop and how do astronauts pee in space, the answer is: technically, just like everybody else, but they use space-dedicated contraptions.

Do Astronauts Wear Diapers?

Well… some do. The early astronauts wore diapers, which NASA proudly called “Maximum Absorbency Garments” (and others called “space poopers”), for their entire mission.

Now the technology has evolved so much so that today they use airflow, the seated space toilet, special waste containers, and even urine recycling devices when on the ISS.

However, diapers are still used when waiting for launch, or when an astronaut goes out on a spacewalk, which can take up to nine hours.

poop in space

3. Undergo Basic Hygiene Habits

So you’ve been in space for, I don’t know, three weeks? And you think it might be high time to give the face a good old shave or get a haircut. The problem? Nobody wants to see hair laying in the sink, let alone float around a space cabin. So what astronauts do is use a hair shaver attached to a vacuum that sucks up all the tiny hairs.

Manicures in Space

But something as basic as brushing your teeth or washing your hands must be a cakewalk, right? The answer here is, still, a big no. So how do astronauts pant their nails?

To avoid poking someone’s eye out, or risking damage to delicate technologies, astronauts clip their nails directly into a vacuum to immediately eliminate the danger.


For hand washing, astronauts use pre-soaped water that comes in pouches. Using a straw, astronauts quirt the soapy water out of the container, after which they trap the weightless liquid with their hands and lather up. There’s no special protocol for drying, though – towels are safe to use in zero-gravity conditions.

But How Do Astronauts Shower?

When it comes to shower in space, things are both similar and different from Earth. If you thought bathing is one of those things you can’t do in space, you are almost right, but not completely wrong either.

Rather than a typical shower, astronauts take sponge baths. From here, things just get more interesting:  

  • Astronauts use liquid soap and water from the aforementioned pouches (rinseless hair shampoo, also). In microgravity conditions, the water and soap suds stick to their skin rather than floating away.
  • They use towels to remove the excess water/soap from their bodies and hair.
  • A special airflow system dries them up quickly so they can go about their day.

How do Astronauts Brush Their Teeth?

The European Space Agency has a few funny videos on how to brush your teeth in space. Meant mostly for kids, these videos make it very clear that hygiene in space is no easy feat.

how do astronauts bathe in space

4. Drink Carbonated Drinks and Alcohol

(This Is Where It Gets Tough)

Among other things you can’t do in space is drinking alcohol and sodas.

Naturally, carbonated drinks such as soda behave differently in space. Thanks to zero-gravity conditions, carbon dioxide bubbles remain within the liquid instead of being released as a gas when opening the bottle. This can cause astronauts great digestive discomfort.

As stressful as it might be to travel into the great unknown, astronauts are barred from unwinding with a cocktail after a long day of running cables and contacting alien civilizations. The issue of consuming alcohol in space is quite complicated.

On the one hand, there’s the belief that drinking alcohol at high altitudes makes you feel woozy faster. But according to science, that’s a myth, as research has found that there is no link between the two.

The woozy feeling in these situations is brought on by altitude sickness, caused when a body is not given enough time to adapt to lower pressure and lower oxygen levels. This can’t possibly affect the astronauts since habitable areas in space maintain sea-level conditions: 101.3 kPa air pressure and 21% oxygen content.

So, why are astronauts barred from enjoying the occasional beer?

Think of it this way: how would you feel if your cab driver, or hell, your jet pilot, would be allowed to drink alcohol? When you put it like that, it seems hardly surprising that the same rules apply to astronauts piloting big chunks of metal worth hundreds of billions of dollars through space.

For the same reasons, astronauts on space stations are not provided products that contain even a hint of alcohol, and this includes aftershave, perfume, and mouthwash.

you cant drink alcohol in space

5. Eat (Normally)

Still wondering about the things you can’t do or have in space? A burger, that’s what!

What Do Astronauts Eat?

Before we explain what do astronauts eat in space, we should first analyze what they don’t, can’t, and shouldn’t eat in space.

Food is still an issue humanity has to figure out before embarking on long space journeys, both due to practical and logistical reasons.

For a food to be considered adequate for space, it needs to meet two criteria:

  • long shelf life, because it’s not like you can run to the nearest supermarket to restock,
  • and safety. Yes, you heard that right – in space, even the most basic of foods can physically hurt people.

The first no-no is bread.

Bread has long been avoided by space programs not only because it lacks structural integrity and shelf life, but because it leaves behind hundreds of crumbs that can float around and cause havoc on the ship.

This was experienced firsthand by Gemini 3 astronauts John Young and Gus Grissom when Young retrieved a corned beef sandwich he had smuggled aboard the capsule. Rather than eat the fragrant snack, however, Grissom stored the sandwich in his pocket after it began to break into pieces.

The same thing applies to salt, pepper, and other granular spices and seasonings, which you certainly don’t want ending up in your eyes in zero-gravity.

But hey, bread is not so healthy anyway so it might be for the best. At least you can enjoy a few pieces of healthy, wholesome veggies, right? Well, not quite.

Vegetables like spinach come in vacuum-sealed packaging, and astronauts have to attach them to a water distributor and fill the bag up until the dry brick of spinach turns into something vaguely resembling edible food.

Again, What Do Astronauts Eat?

Eating in space, while difficult, does not differ much from eating on Earth under special conditions. Astronauts consume vegetables, dairy, fruits, and other frozen/dry/canned/concentrated foods that don’t even begin to match a fresh-out-the-oven hot pizza but represent food anyway.

Do Astronauts Crave Shrimp? What about Tabasco Sauce?

When they arrive in space, astronauts go through a complex series of physiological changes. In zero gravity, bodily fluids go up instead of flowing down towards your feet.

For this reason, research suggests that most astronauts experience puffy eyes, clogged sinuses, lack of taste, stuffed noses, dry mouths, etc. They experience a significant diminishing of their sense of smell – which correlates powerfully with the sense of taste.

In other words, after a while, astronauts reach for hot sauces, spicy, salty, or sweet foods, going through cravings that they may have never imagined back home.

Most astronauts crave Tabasco sauce, hot peppers, and pungent flavors to spice up their life and give taste to the foods they eat.

So why do astronauts crave shrimp? It’s not the shrimp itself they’re after: it’s the horseradish in the cocktail sauce of this tangy side dish. And, probably, they want to feel like humans once in a while.

you can't eat bread in space

6. They Can’t Even Sleep Like Normal People

The next point on our list of things you can’t do in space (properly) is catching some very necessary Zzz…

After a long day of doing whatever astronauts do there, you would think they could just crash into their space beds and get a well-deserved rest, right? Well, not quite. Sleeping in space is a serious matter and we will try to answer some of the most pressing questions on how do astronauts sleep in space, what they sleep in exactly, and how they manage to keep their minds under such adverse circumstances.

How Do Astronauts Sleep in Space?

Sleeping is a little different in space – there is no up and down, and everything is weightless, so astronauts have to adapt to these conditions if they ever want to not get psychotic due to sleep deprivation.

In early missions, astronauts could sleep anywhere, as long as they attached their sleeping bags to a wall or ceiling to avoid floating around the cabin and bumping into each other.

On the International Space Station, there are six private sleeping quarters – little larger than phone booths – to provide a quiet place for each crew member to hang their sleeping bag.

How Many Hours Do Astronauts Sleep?

The schedule says 8 hours, but many cannot sleep more than six. After all, the resting conditions are less than ideal and astronauts have plenty of things to worry about even when they nap.

Despite this, in his book An Astronaut’s Guide to Life on Earth, Chris Hadfield describes the weightless sleep of microgravity as “a whole new type of comfortable.” With no gravity pushing you downward, your entire body is perfectly relaxed.

Zero gravity and the prospect of suffering concussions are not the only things that astronauts need to consider.

  • The sleeping quarters have to be very well ventilated. Why? Thanks to the lack of gravity, astronauts can wake up air deprived, as the exhaled carbon dioxide can hang around in the air, forming bubbles around their heads.

If you let one rip, well, you got a major problem on your hands, as the gas lingers in the air, annoying everybody and inadvertently causing a situation stupid enough that even Jackass didn’t think of turning into a prank.

So, How Do You Sleep in Space?

Very carefully, it is all that we are saying. We would recommend some space sleep music to ease you into that zero G comfort Chris Hadfield was describing, but you may be among the lucky ones that can sleep anytime and anywhere when they are tired. We personally are not among those select few.

To return to more serious facts about sleeping in space, the European Space Agency reported that astronaut hibernation (suspended animation) is doable under certain conditions. Of course, a science-fiction trope so popular it is not even considered a cliche in space travel movies or books is still hard to achieve in real life, but the E.S.A. is hopeful and confident. As you can easily guess, suspended animation could help astronauts travel for unprecedented distances into space and reach not only Mars, for instance, but other galaxies far, far away as well!

sleeping in space

7. Intimacy and Sex

One question that is on many peoples’ (dirty) minds is: do astronauts have sex in space? While technically not impossible, sex, intimacy, and romance become even more complicated than on Earth, if that was even conceivable.

Do Astronauts Have Sex in Space?

Let’s see why sex is one of the things you can’t do in space (unless you try very, very hard):

  • There is not enough comfortable space or privacy to hit it off – cabins are small, bathrooms are basically toilet seats with curtains, sleeping takes place in sleeping bags (on walls or ceilings!), and there are few if any rooms where two people can retreat for some good time.
  • Sex in space may cause people health problems – zero gravity can lead to nausea, which is not the foreplay anyone is looking for. Moreover, in space, astronauts have to deal with lower blood pressure than normal, and… we all know what this means.
  • Carbon dioxide levels are building up, giving the “I have a headache” thing a whole new (and absolutely real) meaning.
  • Last but not least, in space, people are usually so busy and so tired they want anything else BUT engage in even more exhausting activities.

Since humanity took space exploration seriously, there have been a handful of rumors regarding several astronauts doing the hot stuff, but such gossip has never been confirmed.

Nobody said you cannot fall in love in a shuttle or while on the ISS. But when it comes to consummating the relationship, we guess astronauts prefer to wait for a little until they go back home to more proper conditions.

Do Astronauts Masturbate in Space?

If they do, nobody is talking about it. Masturbation in space has never been commented upon by neither NASA or the ESA. The science and trickiness of sex in space is a hot topic and it is going to get even hotter soon, as simulations and theoretical designs for the Lunar Getaway or for Mars Settling are becoming more real by the minute.

things you can't do in space sex

8. Perform Regular Exercises

Astronauts on the International Space Station have a rigorous exercise routine, scheduled two and a half hours a day, six days of the week. However, among the things you can’t do in space is exercise like normal people.

Their equipment isn’t something that might be found at a gym here on Earth. Instead, all of it has been specially designed for space. Three machines give a full-body workout:

  • The bicycle. Unlike the bicycle you might have had as a child, the one on the space station has no seat: the astronaut’s butt wouldn’t stay on it anyway. Instead, there’s a back pad to lean against and handles to grip to remain stationary as the astronaut strengthens his or her legs.
  • The treadmill. In space, when you hit against something – for example the platform of a treadmill -, you bounce away from it. So astronauts must be strapped into this machine with a harness and bungee cords to remain in contact throughout the entire run.
  • The weightlifting machine. Since lifting weights in a weightless environment wouldn’t achieve very much, this machine uses two canisters to create small vacuums that astronauts can pull against to do squats, deadlifts, calf raises, you name it.

Why Is So Much Exercise Necessary?

Besides needing to keep up the rigorously healthy state they maintained as a spaceflight candidate on the ground, astronauts’ bodies aren’t built for space any more than ours are.

Humans have adapted to perform excellently in the gravity well of our planet: take that away and astronauts experience loss of bone density and muscle mass. All that exercising is necessary to counteract as much deterioration as possible, keeping astronauts healthy for when they eventually return to Earth.

things you can't do in space exercise

9. Use Normal Writing Tools

One of the last things you can’t do in space that we put on our list is writing using a pen. You might wonder who in their right mind uses pencils and pens anymore, with so much digital technology available, but if you ever go to space and want to use a pen to scribble your own signature on a document, you can’t. And astronauts hate it. 

Tasks performed regularly on a space mission include making notes about the numerous scientific experiments being run, performing a quick calculation by hand, keep a classic pen-and-paper diary, or even writing a letter home – and none of it can be performed with a normal pen.

A typical pen needs gravity to pull the ink down. Without this fundamental force, when held upside down, for example, or in the microgravity conditions of space, the pen won’t write.

To counter this issue, astronauts on early missions used mechanical pencils to write their reports, until someone invented a special space pen for exactly this type of situation.

The ink cartridge in this pen is pressurized with nitrogen gas, pushing the ink toward the pen’s tip and allowing it to work without gravity.

Since then, the Fisher Space Pen has become widely available for use in harsh conditions such as extreme temperatures or underwater, alongside its use in space.

Writing with pens is not the only piece of a normal workday that the lack of gravity affects.

Everything an astronaut uses must be constantly held or monitored, or else it’ll just float away.

Chris Hadfield notes:

In space, if you don’t hang on to them, things like spoons, pencils, scissors, and test tubes simply drift away, only to turn up a week later, clinging to the filter covering an air intake duct.

A hive of lost spoons and test tubes isn’t exactly desirable, so the walls of the International Space Station are nearly completely covered in Velcro. This provides any number of places to stick your space pen when you’re finished with your report.

An interesting side effect of this unique wallpapering is that the station’s distinct smell is composed in part of, you guessed it, glue.

writing in space

So is Becoming an Astronaut Still a Dream Job?

One can say that astronauts or, better yet, the concept of astronauts is a highly romanticized one. All people can think of is the idea of reaching out for the stars and puffy planets (yes, they are a thing), but ignore the little details like having to go number 2 in a vacuum to avoid any nasty incidents.

Are the Things You Can’t Do In Space Going to Put You Down?

We hope not. As you know, we are huge space exploration buffs around here and we have written about space, the universe, and everything for quite a while now. So if you want to become an astronaut, we want to share with you some sources of inspiration and of learning. So before we see each other again, here is what we recommend:

Is becoming an astronaut still a dream job despite the adversity and the things you can’t do in space? Hell yeah, it is! We mean, sure, the pooping, and the brushing, and all the other inconveniences may weigh heavily, but, at the end of the day, while you dry your hands after washing up with a big bubble of water, you get to see Earth, and nobody can convince us that the view isn’t worth it.

Things You Can’t Do in Space: Resources

Want more science now?

Check out our news page where we post interesting studies and discussions (sometimes mocking them mercilessly) for more.

Pin It on Pinterest

Share This