How do Astronauts Poop in Space?

By: Stephanie Watson  | 
A wide-angle view of the Orbital Workshop waste management compartment. The actual toilet's down the hall, to your right. See more astronaut pictures.
NASA Marshall Space Flight Center (NASA-MSFC)

How do astronauts poop? Regardless of whether you're in your living room or orbiting thousands of miles above Earth in the international space station, when nature calls, you have to listen. But when you're in zero gravity, something as simple as going to the bathroom can turn into a major challenge.

It's disgusting to even contemplate what might happen if an astronaut tried to use and flush a regular toilet in zero gravity. So how do astronauts go to the bathroom in space? Let's just say it's a little more complicated than lifting the toilet seat.


Bathrooms in Outer Space

Each spacecraft comes equipped with unisex space toilets. Although it looks like a slightly higher-tech version of its counterparts here on Earth, a space toilet designed a bit differently.

The bathroom area in a space shuttle consist of a commode that holds solid wastes and a urinal for liquid wastes. A funnel that fits over the genital area allows both male and female astronauts to urinate standing up, although they also have the option of sitting down.


­To prevent the astronauts from floating away in t­h­e weightless environment, the toilet comes equipped with foot restraints (for sitting) and a toe bar to slip the feet under (for standing). The toilet also has a thigh bar similar to the one that pulls down over your lap when you ride a roller coaster and fabric fasteners that go around the thighs.

To ensure that the liquid and solid waste also doesn't float around, the toilet uses flowing air instead of water to flush the toilet. This vacuum toilet pulls the waste away from the astronaut's body and flushes it away. After the air is filtered to remove bacteria and odors, it's returned to the living cabin.

But where does all the waste go? Don't worry, it's not going to come hurtling into the Earth's atmosphere and through your roof. There's a process to collect waste too. Solid wastes are dried to remove all moisture, compressed and kept in airtight containers on-board. They're removed and disposed of once the spacecraft has landed. The liquid waste is sent into space.


How The International Space Station Handles Waste

On the International Space Station, liquid wastes are recycled through a special water treatment plant and turned back into drinking water. Solid waste goes into a plastic bag. Each time someone uses the ISS toilet, the bag clamps down and seals like a trash compactor. The bags are collected and placed into a special craft that is launched into space.

Going to the bathroom becomes even more challenging when astronauts take a walk outside their spacecraft. Because they can't simply drop their space suit and go, astronauts typically use a superabsorbent adult diaper. These diapers are able to hold up to a quart of liquid. Astronauts use adult diapers during take-offs and landings as well. After the spacewalk, the astronauts remove the diapers and dispose them in a storage area in the craft.


But how do astronauts perform other everyday functions like eating and sleeping? How do they keep clean? Go to the next page to find out.

Life in Space

Mission Specialist Fabian sleeps in zippered sleeping bag fastened to the middeck starboard wall on a 1983 mission.
­NASA Johnson Space Center (NASA-JSC)

In addition to using the bathroom regularly, astronauts need to do all of the same things they do on Earth, including eating and sleeping. Of course in space, the lack of gravity makes everyday activities not so ordinary.

With no refrigerator on-board the spacecraft to keep food fresh (although the International Space Station now has fridges), most food is dehydrated and sealed in bags to prevent bacteria and other organisms from growing. The astronauts add water to the food to soften it enough to eat.


Some foods are avoided entirely because even though they are perfectly innocuous on Earth, they can be downright dangerous in space. Crumbs, for example, can float into an astronaut's nose and get inhaled. Hot food can cause nasty burns if it floats onto exposed skin.

Since astronauts themselves can float away while they eat, they first attach themselves to a table with special restraints. They also need to be tethered while they sleep. The sleeping area usually consists of bunks with sleeping bags attached to a wall.

Astronauts can get pretty smelly in their space suits. Because they're in such close quarters, the aroma can become unpleasant to say the least. When they need to bathe, astronauts usually take sponge baths, which are easier to take than showers. They use a wet, soapy washcloth to wash themselves and then "rinse" with a wet washcloth.

Some spacecraft do come equipped with a special "shower" of sorts. It is made of a plastic cylinder that measures about three feet around. The shower is completely enclosed by a sleeve that reaches from the floor to the ceiling to prevent water from floating away.

The astronauts spray themselves with water from a nozzle to rinse off and use a vacuum hose attachment to suck up all the water from their skin and from around the shower itself.


Lots More Information

Related HowStuffWorks Articles

More Great Links

  • "Astronauts and Life in Space." Cornell University.
  • "How Do You 'Go' in Space?" BBC News.
  • "Living in Space." NASA.
  • "A Moment of Science." The Trustees of Indiana University.
  • "Plumbing the Space Station." NASA.
  • Pogue, William R. How Do You Go to the Bathroom in Space? Tor/Forgue, 1999.
  • Spangenberg, Ray and Diane Moser. "At Home on the Space Station." Final Frontier, August 1998, pgs. 23-26.
  • "Waste Collection System." NASA.
  • "What do Astronauts Eat in Space?" Curious about Astronomy?