How to go to the Toilet in Space

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"What's it like looking down on the cradle of humanity?"
"Does it make you feel small to look out at the stars and wonder where our place is in all this?"
"Have you ever seen an alien?"

These are all questions that could be directed to astronauts, those lucky few who are given the opportunity to spend time amongst the stars. It's something that most of us could only dream of, so when astronauts talk to members of the public they expect a degree of enthusiasm about what it's like up there. But apparently one question is asked quite often, and it concerns curiosity about how to go to the toilet in space.

It's something we do daily here on Earth, so it's not surprising to hear that people want to know just how they're going to empty their bladders when they're in the darkness of space. Admiring the beauty of our planet is all well and good, but if you really need a wee when you're doing it then it's somewhat going to mar the experience.

We've grown used to being able to drop our pants and sit on toilets like these whenever we want, but it isn't as easy as that in space. So we decided to look into how astronauts get the job done, how complicated it may be and just where all that waste goes when there are no sewers around.

Taking a Leak in Space

With NASA concentrating on getting the first American man into space, maybe it hadn’t given much thought to what would happen if an astronaut needed to relieve themselves after they had been shot into space. But why would they? The first flights weren’t planned to be long. Yuri Gagarin, the first human in space, was only up there for 1 hour and 48 minutes. The astronaut would just have to wait until they were back on solid Earth.

But as anyone who follows the history of human spaceflight knows, missions don’t always go to plan. Take the first manned American space flight on May 5, 1961, for example, in which Alan B. Shepard Jr. sat waiting for launch in a mission that was only supposed to last 15 minutes. Technical difficulties and bad weather would leave Shepard sat waiting for launch for over 4 hours. That’s a long time not being able to go, and eventually Shepard gave in.

Radioing control to tell them that he needed “to pee” he was firmly told that he wouldn’t be able to do that. NASA hadn’t included anything that would allow him to go, and his suit included delicate instruments that could break if they got wet. But a man’s bladder won’t hold for long, and they had no choice but to let him wee inside his suit.

Apollo Urine Transfer System NASA Logo

If you don’t think that urine could cause much of an issue, you’ll be surprised at how much the problem would continue to plague NASA. In 1963, astronaut Gordon Cooper was carrying out the last Project Mercury flight. By this point, NASA had created a device that could collect urine that could be worn by the astronaut cramped inside a one-man spacecraft. Cooper would complete 22 orbits around the Earth throughout his 34-hour mission, but as the end was nearing systems on board the spacecraft began failing. This meant that Cooper had to manually pilot the spacecraft back into the atmosphere. This major issue proved that NASA’s urine collection devices weren’t infallible, as the systems failure had been caused by a leak in the urine device that caused urine to enter delicate electronics.

Even by 1984, urine was still causing problems for NASA. When the waste water venting system failed on the space shuttle Discovery, a large icicle made of urine formed on the outside of the shuttle. As this icicle could break free during re-entry, possibly damaging the shuttle's protective heat tiles as the icicle shot away, it had to removed using the shuttle’s robot arm. Unfortunately, the crew also had to shut down the urine collection system, which meant that they had no working toilet for the rest of their six-day mission.

A Poo on the Moon

While it was hard enough for early astronauts to pass liquid in space, consider how tough it would be to get rid of faeces without the interior of a spacecraft becoming very messy. Longer missions meant that astronauts would need to be able to do both reasons for going to the loo, so NASA went back to the drawing board.

Fecal Containment NASA Logo

The solution was a plastic bag. Astronauts Jim Lovell and Frank Borman would spend 14 days in space inside Gemini 7, which is made to test manoeuvres to be used in the Apollo missions to the moon. By the time that Neil Armstrong, Buzz Aldrin and Michael Collins made their historic trip to land on the lunar surface, NASA had refined the plastic bag device to include an adhesive that the astronauts could stick to their rears. But it could still be messy as the astronauts still had to ‘separate’ the bag from their skin. This meant that astronauts would often have to strip naked to avoid getting poo on their clothes and you had to be so careful that the process could take around an hour to complete. We’re all guilty of sometimes spending longer than we need to in the bathroom, but this takes the biscuit when all you want to do is go for a poo!

The Space Toilet Arrives

Toilet on the International Space Station Logo

In 1978, NASA began recruiting women for the astronaut corps. They immediately discovered that NASA hadn’t designed anything that would let women go to the toilet in space. Male astronauts were peeing into a tube designed for the male anatomy, so NASA had to design something that would use air to pull waste away from the user due to the lack of gravity in space. That design would come to be known as the Waste Collection System (WCS).

Even though the toilets that were used on the space shuttles - plus the refined design now used in the International Space Station – look somewhat similar to the western toilets we use here on earth, the way they worked was obviously very different thanks to being unable to use water to flush waste away. Instead, they used a fast-flowing air flow and something called a “slinger” that would collect the waste and propel it to the side of the bowl. Fans situated here would separate liquid and solids, whereupon liquid was dumped into the vastness of space. The solids were dried using the vacuum of space and stored on board for emptying once the shuttle returned to Earth. It was a complicated system that relied on everything working together perfectly. Astronauts also had to clean it regularly to keep it running smoothly.

There were numerous problems with the initial shuttle flight, resulting in NASA returning the toilet to the contractor to improve it. Thankfully it became a lot more efficient over subsequent missions, and today the International Space Station has toilets that are far more refined than their predecessors. But like their predecessors, the toilet still requires some training to use.

Toilets on the International Space Station

The International Space Station Logo

Using the toilet here on Earth has become second nature. It’s something we learn to do early on in our lives, so the idea of training to use one again sounds quite strange. But the toilets on the ISS do a lot more than the one in your bathroom, and because of where they are situated things can end up getting very messy if you don’t know how to use one properly. As such, astronauts train to use the commodes before they blast off by learning how to position themselves correctly over a smaller than usual hole. Leg restraints also have to be used due to the microgravity, so going to the toilet takes a lot more work than we're used to. Watch the video below to see what the training toilet looks like.

The ISS is home to two toilets; one is in the Russian Zvezda module and the other sits in the NASA/ESA module, Tranquility. They are similar in design to the WCS system used on the space shuttles in that they use fans to separate liquids and solids.

For when astronauts need to take a leak, a liquid waste vacuum tube is used. The end of this has a funnel on that male astronauts position themselves a few inches away from before they begin reliving themselves into it. As the female anatomy is different, the funnel females use is different in that it is oval shaped and is placed up against the user and has small air gaps around the rim to reduce suction. The waste is then sucked away from the body and down the vacuum tube using a fan that provides suction.

Both liquid and solid waste enter a vacuum chamber. This is a cylinder in which waste collection bags can be clipped to and includes a fan to provide suction. Urine is collected into waste storage drawers and is later filtered by a filtration system to turn the urine back into drinking water. While it does not convert 100% of the waste into drinking water, scientists are working on making the process even more efficient.

Solid waste is stored in a detachable bag that is filled using the fan within the vacuum chamber. This bag is made from a fabric that allows gas to escape to prevent a build-up. When the astronaut is finished, the bag is sealed and placed into a waste storage drawer for future disposal. Once these containers are full, they are moved to the Progress module and blasted into space with other rubbish from the ISS so that it can burn up in the atmosphere.

Even though toilets are now available, the time and effort required to use them for anything other than a simple wee means that astronauts regularly a low-residue, high-protein diet before launch to minimise the need for defecation.

So, while scientists and engineers have solved the issue of how to go to the toilet in space, there's always room for improvement and we'll no doubt hear about new technology that will increase efficiency in the future. For planned long trips to Mars, NASA and other space agencies will have to develop new methods of ensuring waste can be safely disposed of. One such system is the Universal Waste Management System that NASA is developing for when the Orion spacecraft is completed. This will be a more compact version of the existing models and will also be lighter, quieter, more hygienic and more reliable to ensure it can be used on long-haul trips. It will be tested in the ISS in 2018, but for now, you don't have to hold it in whenever you blast off to the stars.

Sources and Further Reading

Plumbing the Space Station - NASA

The Apollo CSM Logistics Training Manual - NASA

Apollo Waste Management System - NASA

Diagram of the elements of the Space Shuttle WCS - Wikipedia

Top 10 Moments in Space Bathroom History - How Stuff Works


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