How Astronauts Answer The Call of Nature in Space

Last Updated: December 22, 2023

Picture this: you’re launching off into space in a high-tech spacecraft after years of preparation to explore the vast greatness of our solar system, to look down upon planet Earth in all of its spherical glory, to witness the true brightness of the sun, to see the never-ending blackness of the void beyond what most humans will ever be able to see, to only come to realise that being in space changes nothing.

You are indeed still human.

And you do indeed still have human needs and bodily functions. Oh yes, this includes having to use the loo in space! So how exactly do astronauts do their business in zero gravity?

At first, there was no space toilet...

Well, the task itself has always proved a challenge! Since the very beginning of space travel, it seems coming up with a simple and effective method for how astronauts can urinate and defecate has left many NASA engineers scratching their heads. 

The very first American astronaut, Alan Shepard, that got sent into space had to urinate in his spacesuit due to a delayed launch time, but also the fact that no toilet was available as he was only due to being up in orbit for a small amount of time – and very little thought had been put into just how an astronaut would do their business in outer space! 

By the time Apollo 11 was launched in 1969, NASA had come up with something they called ‘roll up cuffs’ that astronauts would use to urinate into, however, these were not suitable for women at all, and to defecate the astronauts had to strap a plastic bag to their backside, which wasn’t 100% foolproof either, (as during the mission one NASA transcript reads that astronaut Tom Stafford abruptly asks for a napkin due to faecal matter floating through the air), and then knead the faeces to mix with a liquid bactericide to stabilise the matter so that they could safely bring it back to Earth without the bag exploding from gas-expelling bacteria. 

The urine was expelled into space but NASA insisted that the astronauts brought their waste back for it to be inspected and examined, and the results have since been published and you can read the complete log online!

Due to the messy nature of these bags, it’s reported that many astronauts took laxatives before they were scheduled to launch and even took medication which slowed the functions of their intestines down. However, these bags couldn’t be used whilst on the moons surface, so astronauts had to change into what was effectively an adult nappy! 

But it wasn’t just the bags that proved to be problematic, going back to the last Project Mercury flight which took place in 1963, astronaut Gordon Cooper found himself having to manually navigate the spacecraft back into re-entry of the Earth’s atmosphere as all the systems onboard started failing, NASA discovered that the urine bag he had leaked and droplets had got into the electronics. Naturally, a cause for concern seeing as liquids and electronics don’t mix particularly well! 

first space toilet on skylab
The first ever space toilet was created for Skylab

Going to the toilet while in microgravity ain't easy!

It wasn’t until Skylab, NASA’s first space station in 1973, that a toilet was invented as this was a necessity as astronauts were going to be living in space for a good few months at a time. The toilet consisted of being a mere hole in the wall which was hooked up to a fan and a bag. 

After doing their business, astronauts were required to vacuum-dry the faecal matter so that it could either be dumped into the waste tank or kept to be studied. By the time the ISS (International Space Station) came to exist in 1998, there had still been little in the ways of progression as the toilet onboard had been designed with men in mind, so this again wasn’t the most suitable for women, as astronauts were required to urinate whilst standing up. 

To defecate they had to strap themselves to the seat to create a suction between themselves and the loo but this too proved to not be 100% foolproof again as it didn’t always work successfully, and was hard to keep clean! 

Expelling urine into space has also proved to be another problematic matter, as when the Soviet Union space station known as Mir (launched 1986) was retired in 2001, it was found that the solar panels had lost around 40% of their effectiveness. This was mostly due to the frozen urine damaging them as it was floating around at such high speeds! Nowadays on the ISS, all urine goes through a filtration system which recycles it into clean drinking water. 

But due to the fact astronauts have had very choice words when it comes to using the toilet, specifically how it was their least favourite part of space travel, in 2018 NASA spent $23 million on a new and improved toilet on the International Space Station. It was a vacuum toilet that consisted of a hose and funnel, which was used for urinating, and a raised seat for defecating. The astronauts can either sit or stand to urinate, so suitable for both men and women, and would just have to hold the funnel tightly against themselves to prevent any leakage. 

Upon lifting the raised seat the toilet would start its suctioning function straight away to prevent anything from getting away, as well as to control odour, and to make sure this was as effective as possible the seat itself is a lot smaller than standard home toilet seats. Whilst the urine gets recycled, faecal matter that isn’t kept to be brought back to Earth to be studied gets vacuumed into bags which are then kept in airtight containers, those containers are then eventually loaded into a cargo ship that has brought supplies to the ISS, and then that ship is launched at Earth and burns up in the upper atmosphere. 

If you were looking up at the sky when this happened you would just think you had seen a shooting star!

Play Video about how to use the bathroom on the ISS video

In this video, Expedition 63 Commander Chris Cassidy explains in great details how astronauts poop and pee onboard of the ISS.

Urine is recycled into drinking water

NASA’s latest innovation aboard the International Space Station has set a new precedent in space technology. The new system, part of the Environmental Control and Life Support System (ECLSS), efficiently recycles up to 98% of wastewater, including astronauts’ sweat and urine, transforming it into drinking water surpassing Earth’s standards.

This advancement, achieved through a sophisticated combination of distillation, brine processing, and filtration, not only bolsters life support in space but also holds potential applications for water conservation on Earth, particularly in areas grappling with water scarcity.

How will astronauts go to the bathroom whilst on the Moon?

Twice now NASA has gone down the crowdsourcing route for help with inventing an all-new toilet system. Once in 2016 and then again in 2020, both contests paying a substantial amount of money to the winners! 

The latter competition, aptly named the “Lunar Loo Challenge” was conducted with the 2024 mission in mind of astronauts returning to the moon, so NASA was after designs that would work effectively, whilst being energy efficient, in both microgravity and in lunar gravity, as the toilets onboard the ISS work in microgravity only – so something entirely new would have to be developed to prevent astronauts from having to turn to the ol’ adult nappies once again! 

The competition ran from 25th June 2020 through to 17th August 2020 with the winner being announced on 30th September 2020 for the technical category. NASA did also have a junior category so that young minds could get involved and have a chance of winning some NASA goodies, as well as an official certificate, and NASA recognition! 

The upcoming toilets for the next moon mission should hopefully be better than ever, as NASA were after a more effective and efficient toilet, one that would use significantly less energy, and be just as easy to use as a toilet here on Earth. 

It will be quieter, be much faster to use and clean, hopefully around 5 minutes, (as in the past astronauts have reported it could take up to 45 minutes for them to finish using the toilet from start to finish), and naturally, it must accommodate all genders being able to use it with ease, including being able to hold a certain amount of vomit and diarrhoea – noting that the competition mentioned ‘bonus points’ for designs that didn’t require astronauts from sticking their head in the toilet to vomit. 


Written by Amy Gent

A spiritual witch and Mother of 2, preferring the lore of my own reality! Outside the weird and wonderful world of my craft, I like to cosplay and fully dive into the fantasy genre across all forms, from books to video games and everything in between. Check out her Instagram.

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