For the several months that astronauts spend on their missions, the International Space Station is home. But it’s also where they work, and all workplaces have rules. And when your office is 400 kilometers up in space, those rules can get strict. So there are lots of things that you’re allowed to do down here, that you absolutely can’t do if you’re an astronaut. One big rule in space no. Sex. Allowed.

The International Space Station, which is the only place where humans currently live in space, only has about 388 cubic meters of living space for a full crew of 6 people. That’s close quarters. So needless to say, an intimate relationship could complicate things.

Plus, astronauts are considered civil servants and colleagues who have to work with one another every day so they need to keep it professional, even if they’re living together too. On top of that, we’re not really sure what would happen if an astronaut got pregnant in space. Without gravity, and Earth’s protection from cosmic radiation, there could be a lot of risks for a developing fetus. The bumpy ride, and close quarters on a return trip wouldn’t be great for a pregnant astronaut either.

And speaking of things that aren’t good for pregnant people, booze! Alcohol is another thing that astronauts cannot have in space. They have to keep their wits about them on the space station at all times of course, and there's a lot of delicate equipment and experiments that can easily be ruined by a drunk astronaut. But this has not been the rule for all space travelers.

Russian cosmonauts have been allowed, and even encouraged to drink in space since the 1980’s. But something about booze in space has always struck a sour note with the American public. For example, after the announcement that Sherry would be on the menu aboard Skylab, America’s first space station in the 1970’s, angry letters flooded into NASA headquarters. Some people were just not okay with astronauts drinking in space.

After that, NASA created a no-booze policy, and so far, it’s stood the test of time. On Apollo 8 for example, astronauts got miniature bottles of brandy to enjoy with their Christmas dinner. But Frank Borman, their commander, ordered them not to drink it until they got back to Earth. 

Now, not only can’t astronauts not drink alcohol, they also aren’t allowed to have bread. Or anything that creates crumbs. An astronaut on the 1969 Gemini 3 mission smuggled a corned beef sandwich into space, but after one bite it crumbled apart, and crumbs went *everywhere*. As crumbs float around a spacecraft, they can get into scientific equipment or important air vents.

Plus, if you’ve ever gotten dust in your eye, or accidentally inhaled a piece of food, you know how unpleasant *that* can be. So partially to avoid the crumb situation, astronaut food was mostly tubes of goo or bite sized cubes of compressed dehydrated food. By the corned-beef incident in 1969, the food was getting closer to normal, but it was still all coated in gelatin to prevent crumbs.

Now that astronauts remain in space for months, and food technology keeps getting better, the food in space is much more like regular Earth food. Just tidier, and without bread. For example, foods like sandwiches and pizza are possible, but they’re served on tortillas instead of bread or crust. And it’s a good thing that astronaut food isn’t messy, because astronauts also aren’t allowed to do laundry.

They wear the same underwear for 3 or 4 days, and some astronauts will wear the same work outfit every day for months without washing it. There just isn’t a way to wash clothes in space efficiently, and washing it by hand would be a waste of the limited water they have on the space station. Lucily, things don’t get dirty as quickly on the space station. It’s very clean and temperature controlled, and astronauts' sense of smell isn’t as good in space, so BO isn’t as much of a problem.

But they do have to work out a lot to maintain their muscle and bone mass. So astronauts' clothes eventually get dirty. And when they do, they’re packed up with the rest of the station's garbage and sent to burn up in the Earth’s atmosphere. This solution seems a bit wasteful though, so in the future, astronauts might feed their underwear to bacteria.

The bacteria could digest the dirty undies and release useful methane gas that could help *power* the spacecraft. An underwear powered spaceship. Why not? The point is there are rules in space. And not just that you can’t go faster than the speed of light, or that you can’t step outside without a spacesuit on.

If you want to have sex, have a beer, or simply do a load of laundry, you’re just gonna have to wait until you get home.

For some people, those first few months back home, have to be a pretty great time. And I mean because of the sandwiches and the fresh laundry smell obviously. If you aren’t allowed to have bread though, what do people eat up there?

Well there have been plenty of myths about space food over the years. Like the whole thing about tang. So we did some debunking. Here’s Reed with more.

Astronauts have to clear a lot of bars to get to space. Education, physical fitness. We expect our space explorers to be the best of the best. But they’re still human. And sometimes, humans can be picky eaters.  So not only, does the food we send on space missions have to be lightweight, shelf stable, and safe for eating inside a space capsule. It has to taste at least okay.

So scientists have come up with really creative ways to keep astronauts fed for days and months at a time. Some of the stories of their success have been exaggerated though. But even some of the misconceptions can tell us something about the challenges of eating in space.

First up, is the belief that NASA developed the powdered drink mix Tang specifically for space. The famous friendship between Tang and NASA goes back to 1962. That year, John Glenn became the first American to orbit the Earth. And while the world watched on television, he drank a powdered beverage out of a pouch labeled “orange drink”. That was Tang.

From then on, NASA and Tang were forever married in the public imagination. But Tang was already available as a consumer product. Just one that hadn’t really caught on yet.  For early astronauts however, the flavored powder was a boon.  See, on early space missions, drinking water was either stored in metal tanks or made from fuel cells. Hydrogen fuel cells generate electricity by joining together hydrogen and oxygen, and as a byproduct, they make water.

Either way, space water tasted like metal. And Tang could cover up that taste. And as a bonus, it also offered astronauts a few vitamins. 
So NASA went all in on Tang. They repackaged it in a microgravity friendly pouch, but other than that, it was the same product. Astronauts just had to add water, stick in a straw, and drink. NASA didn’t invent Tang, the two did enjoy a frightful relationship. In fact, they’re together to this day.

Now, to the second misconception, is the idea that everything in space is freeze dried, and that there’s no “normal food” at all. It’s true that astronauts eat a lot of weird stuff in space. Back in the day, they squeezed pureed meals out of what looked like toothpaste tubes, and ate it cold.

Even now after decades of space food R n’ D, astronauts still eat a lot of re-hydrated food out of airtight pouches. But, these days they also eat a lot of normal things.

For instance, they can eat fresh fruit. At least for the first few days of a mission while it’s actually fresh. On holidays like Christmas and Thanksgiving, they get turkey. The International Space State even has the occasional pizza night. Today, there are around 200 items on NASA’s space menu. It includes things like scrambled eggs, fish casserole and nuts.

Being able to choose from lots of foods they like, is a real morale booster for astronauts. And they’re psychological health is important, especially on long missions. Still it is true that most of the astronauts' food has to be carefully prepared and processed, unlike on Earth.

There’s typically is no fridge or freezer in space, so all food has to be shelf stable. That means it's often freeze dried, powered or packed in airtight pouches. And it’s taken a lot of work to figure out what that food should even be. At first, NASA adopted army food, but it turns out the high salt and fat that’s good for soldiers, isn’t great for astronauts.

So food scientists have spent years testing and modifying foods to come up with today's vast menu for space. And finally, even though most astronaut food is processed, it doesn’t look like that foil wrapped, chalky stuff you buy in museum gift shops. You know those blocks of so-called “space ice cream” that do not resemble ice cream at all.

That stuff has never been to space. It does have a real connection to real space food, but a very distant one. Freeze dried ice cream actually *was* developed for space flight way back in the Apollo era. Engineers made it by freezing regular ice cream and using a vacuum pump to evaporate the ice, thus preserving the ice cream--sort of. It worked well enough to make it into the plans at some point. A press release that went out before Apollo 7 said that freeze-dried ice cream was going to space.

It just never got there. The astronauts on that mission say they never squaw it and it hasn’t come to space since. The only ice cream that astronauts get in space is the occasional scoop of the real stuff. Which sometimes goes up in a freezer intended for taking medical samples back to Earth.

We've come a long way since astronauts were sucking food out of tubes with straws. It's taken a lot of ingenious ideas to get here, and the future of space travel will need even more creativity. Like space farming. Yes, scientists are now working on growing food in space. Since that's the only real way we can feed astronauts on long distance missions.

It’s no surprise that all this space age science leads to some confusion. But it’s all in the name of keeping astronauts healthy and happy. Bon appetite. 

Ehh! Space pizza parties. That’s--that’s adorable.

Now let’s be real. If you’re eating a bunch of food, your body is going to turn that into waste. And that waste, it has to go somewhere., just like it does on Earth. Except the whole business of doing your business in space definitely is different than what you are used to. Here’s an old Scishow Space with more.

So. You want to be an astronaut. 

Well, one of the many surprisingly difficult things you’re going to have to learn is how to do your business in space. By which I mean like peeing and pooping and stuff. As you might imagine, it’s a little bit tricky. And training beings well before you strap in for that trip to the International Space Station.  Learning how to defecate in a microgravity environment first of all is the opposite of glamour.

On Earth, we sit on a toilet seat that’s between 30 and 45 centimeters in diameter. In space, you’ll be working with an opening that’s about 10 centimeters wide. Because you know, you want to make sure that it all stays where you put it.

So NASA has learned over time, and I don’t want to know how, that the best way to train astronauts for this is by installing a camera inside the toilet. Allowing astronauts to watch on a nearby monitor as they figure out how best to position themselves, and avoid any unfortunate mishaps. Once they’ve mastered that part of the process, astronauts use restraints to help keep them in place. So you don’t float away, while you’re doing your business.

The toilet itself works like a vacuum cleaner, using differential air pressure to suck the solid waste away. That waste is then stored for the remainder of the mission. And yeah, it could be jettisoned out into space, but ISS officials decided it would be best not to have astronaut poo orbiting the Earth at 28,000 kilometers per hour, along with all the other space junk up there.

Urinating meanwhile requires an entirely different contraption. Each astronaut gets his or her own personal urinal funnel. Which is attached to a hose adapter. Fans suck the air and the urine out and into a waste water tank. Naturally, there are different setups for male and female astronauts, and it’s actually easier for the women. They can place their funnels directly against their bodies, which adhere to them, and then the suction is turned on.

Male astronauts have to be a bit more careful though. They have to hold the funnel come close enough that it’ll collect the urine, but not so close that they get vacuumed in when the toilet’s pressure is activated.

Though this sounds like pretty simple equipment, the ISS toilets are not cheap. The newer versions cost about $19 million dollars. And until recently, all collected urine was released into space when the waste water tank filled up. That changed in 2008 when astronauts and cosmonauts aboard the ISS began to use a new system designed to purify or distill urine into water to be used for drinking and bathing.  Here on Earth, distilling water is a pretty simple process.

Here on Earth, distilling water is a pretty simple process: boiling the water and then letting the steam cool and condense back into pure water. But it's a bit more complicated in space where the lack of gravity prevents contaminants in urine from separating from the steam, so the ISS creates its own kind of artificial gravity for this purpose, spinning its keg-sized distiller while boiling the liquid. The steam goes to the middle where it can be filtered out while the waste falls to the sides of the container. Despite some early kinks, the system works as astronaut Don Pettit said, "yesterday's coffee becomes today's coffee." 

So if it's so easy, why don't we do that on Earth? Well, the setup on the ISS costs about 250 million dollars, so, yeah. But now that they're getting the hang of things, scientists are trying to take the process a step further by using urine to generate electricity in addition to drinking water. NASA is currently testing a system that uses a process called forward osmosis which effectively pulls water out of urine using a concentrated solution of salt and sugar. The leftover nitrogen-rich waste from the urine can then be converted into ammonia which can be used as fuel for generators that make electricity. Now if we could only find something equally useful to do with our space poop. 

That urine collection system will give you nightmares. Thankfully, not all stories about bodily functions are not quite so potentially alarming. Like, during the Apollo program, while NASA was still trying to figure out what people should eat in space, there was the farts incident. Yes, I said the farts incident. I’ll let Reed tell ya more.

Stories about human spaceflight are usually full of heroism, math, and the triumph of human ingenuity over incredible odds. The story of how an astronaut got the farts on Apollo 16 is no exception. It all started on the Apollo 15 mission, which landed on the Moon in 1971.

The mission was successful, but while they were in space, the astronauts experienced some arrhythmia, or irregular beating of the heart. Arrhythmia can signal all kinds of serious cardiovascular problems, like heart attack and stroke. So even though the astronauts made it back just fine, NASA very much wanted to make sure that astronauts on future missions avoided arrhythmia while they were in space, where humans have yet to establish any solid healthcare infrastructure.

So NASA physicians did some bloodwork on the Apollo 15 crew when they returned to Earth, and found that they had too little potassium in their systems, a condition called hypokalemia. Potassium is super important for your heart because it’s a major part of nerve cell function. And your nervous system is what controls your heartbeat.

Specifically, potassium is used in the sodium-potassium pump, which is found in all kinds of cells, including those in every part of the nervous system. An enzyme separates out the sodium and potassium on either side of a nerve cell’s membrane, building up voltage across the cell surface. For carefully timed bursts of cellular activity, you usually want the cell’s membrane to reach a particular voltage before firing, called the action potential.

Once you hit that voltage, the cell fires; otherwise, it just waits for the voltage to build up again. A network of nerve cells throughout the heart rely on the sodium-potassium pump, among other cell-signalling pathways, to time your heartbeat. If components of that system fall out of whack, like if you aren’t getting enough potassium, your heartbeat can get off-kilter.

So be sure to eat your bananas, friends. But back to our astronauts. To keep the Apollo 16 astronauts safe from the arrhythmia experienced by the Apollo 15 crew, NASA prescribed a ton of potassium.

Not enough to mess up the sodium-potassium pump in the other direction, but still a whole bunch. Potassium is typically very bitter, so it needs to be dissolved into something with a lot of flavor. NASA decided to use lots of citrus drinks.

The crew had various citrus-flavored rehydratable drinks that they had to drink every day, multiple times a day. As you can probably imagine, the astronauts got really tired of this. And the diet had some physical downsides, which we know because NASA records all its communication with astronauts and makes the transcripts publicly available.

At one point, the mission commander, John Young, was unaware that he had a hot mic, and well, I’ll just let you listen to what he said to fellow astronaut Charles Duke. “I’ve got the farts, again. I got ‘em again, Charlie. I don't know what gives ‘em to me.

I think it's acid stomach, I really do. I haven't eaten this much citrus fruit in 20 years! I’ll tell you one thing, in another 12 days, I ain’t never eatin’ any more.” So of course the press reported this, and because farts are always funny, everyone had a good laugh about it.

That is, everyone except for Florida Citrus Mutual, the organization representing Florida’s citrus industry. They issued some official statements saying that the astronauts were using artificial citrus drinks, and not wholesome, Floridian OJ, part of this complete, balanced breakfast. So citrus is not to blame, and they would like you to please continue to buy their products.

And that was true. The flatulence wasn’t caused by fruit. It was the potassium.

See, potassium is used in another enzyme pump, in the digestive system. It’s the hydrogen-potassium pump. Your stomach acid is kept nice and acidic by an enzyme that pumps potassium in and hydronium ions out.

The hydronium quickly dissociates to regular water and free hydrogen ions. Having free hydrogen ions in a solution is what makes it acidic. In fact, pH stands for “power of hydrogen.” So all the extra potassium the astronauts were taking in caused the hydrogen-potassium pump to overwork, which gave them “the farts.” But their heartbeats were good and steady, so at least they solved that problem!

There has actually been a great deal of research into space farts by NASA, because they pose a safety hazard. Methane is a flammable gas, so having a container of people emitting flammable gas on top of a rocket could conceivably pose some problems. But the amount of methane the Apollo 16 astronauts produced didn’t cause a fire, and the astronauts didn’t experience any arrhythmia.

So unfortunately for the Apollo 17 crew, NASA physicians required the potassium diet for them, too. 

Florida citrus. Gotta keep their brand squeaky clean. Generally if you’re going to be working in space, you’ll probably be involved in a few space walks. Moments where you get to step outside the space station and go fix or install something. And if you want to prepare for that day, there is actually something you can do now to practice, work on your handshake. Here’s Caitlyn with one more episode.

Do you dream of becoming an astronaut? How’s your handshake? Firm? Confident?

If you’re an astronaut, spacewalks are an important part of the job. But, it turns out, spacewalks have nothing to do with your legs at all. Pretty much everything you need is in the palm of your hands.

On March 18th, 1965, the cosmonaut Alexey Leonov went on the first ever spacewalk. His mission was just to survive, and try to take some pictures. Since then, spacewalks, also known as extravehicular activities, have become an important part of most space missions.

From repairs and modifications, to setting up science experiments there's a lot to keep astronauts busy on the outside of a spacecraft. But spacewalks are just one of many extreme situations that astronauts can go through: There’s living in weightlessness, touching down in the Pacific ocean, dealing with huge g-forces, or staying awake for a triple-shift of emergency repairs. Which means they have to be super fit to handle all that stress on their bodies.

Astronauts undergo lots of physical tests, from weight checks to eye exams. Not to mention military water survival training, which includes swimming 75 meters, and treading water for 10 minutes – all in a flight suit and tennis shoes. They spend hours practicing spacewalks in the pool, because it's a great way to simulate weightlessness. Rehearsing in water helps astronauts get used to equipment and practice repairs, but also helps strengthen important muscles. And the muscles that are most important for spacewalks aren’t in your legs – they're in your arms.

Spacewalks actually don’t involve “walking” at all. Your legs and feet mostly just get in the way – muscles in your hands and forearms let you maneuver around in space. So not having a good grip could be a nightmare. Astronauts are safe because they're always tethered to the spacecraft. But can you imagine spending 5 to 8 hours weightless in space, holding on to railings and juggling power tools? It isn't easy.

To make matters worse, spacesuits are designed to be pressurized and stiff, making the gloves naturally stretched out. Fighting against that stiffness to hold onto something can be exhausting and your hands also take a real beating. A 2005 study on 770 NASA spacewalk training tests found that around 47% of symptoms and injuries were in the hands – more than double the shoulders, which were 21% of the symptoms. Those injuries included everything from sprains and blisters, to completely detached nails. And yes, those detached nails can happen on a spacewalk.

When you're in a spacesuit and trying to grip something, your fingers tend to hit up against the walls of the glove. The inner layer is made of a rubbery balloon-like material, but when it’s pressurized it becomes rock solid. Circulation issues can also arise by the glove putting pressure on your finger joints, and all that can lead to infections in the exposed tissue. It can be such a problem that a few astronauts have been known to get their fingernails removed and nicely bandaged up before going to space.

Astronauts can even develop repetitive strain injury, or RSI – that's the same condition gamers can get in their hands from mashing buttons over and over again. So even if you’re lucky – you don't get RSI, and your fingernails hold it together – it's still hard to avoid those tired, achy muscles by the end of a spacewalk. But sometimes the most frustrating problems can bring about some of the coolest solutions.

NASA is working with General Motors to develop a Robo-Glove, which just sounds awesome. It responds to pressure from your hand movements, and could double or even triple astronauts' grip strength. In space, a similar technology has only been tested in a fully automated robot called Robonaut 2, which was sent to the ISS in 2011, and has been busy helping astronauts ever since.

But engineers are already working to find a way to integrate the Robo-Glove into a future spacesuit. So, if you dream of becoming an astronaut, the selection process and the job are both pretty grueling. For several reasons, you'd better practice your handshake. No limp wrists in space, people!

For all of our future space explorers out there, good luck. Really, we are rooting for you. And for the rest of us who might rather just stay on Earth, there’s always more Scishow Space.  We put out new episodes twice a week, and we’re always talking about the latest discoveries and coolest stories from history.

If you want to keep up with all of it, you can go to youtube.com/scishowspace and subscribe.