Personal Hygiene in Space: How it Works

Space shuttle toilet
NASA Space Toilet. Wikimedia Commons

There are many things we take for granted here on Earth that take on a whole new aspect in orbit. One of the most-asked questions that NASA receives is about bathroom rituals. All human missions have to deal with these issues. In particular, for long-duration missions, the management of ordinary daily habits becomes even more important since these activities require sanitary conditions to operate in the weightlessness of space.

Taking a Shower

There used to be no way to take a shower on an orbital craft, so astronauts had to make do with sponge baths until they returned home. They washed with wet washcloths and utilized soaps that do not require rinsing. Keeping clean in space is as important as it is at home, and even doubly so since astronauts at times spend long hours in space suits wearing diapers so they can stay outside and get their work done. 

Things have changed and nowadays, there are shower units on the International Space Station. Astronauts jump into a round, curtained chamber to shower. When they're done, the machine suctions up all the water droplets from their shower. To provide a little privacy, they extend the curtain of the WCS (Waste Collection System), the toilet or bathroom. These same systems may well be used on the Moon or an asteroid or Mars, when humans get around to visiting those places in the near future. 

Brushing Teeth

It's not only possible to brush your teeth in space, it's essential since the nearest dentist is a few hundred miles away if you get a cavity. But, tooth brushing presented a unique problem for astronauts during early space travel. It's a messy operation—you can't really just spit in space and expect your environment to stay tidy. So, a dental consultant with NASA's Johnson Space Center in Houston developed a toothpaste, now marketed commercially as NASADent, that can be swallowed. Foamless and ingestible, it has been a major breakthrough for the elderly, hospital patients, and others who have trouble brushing their teeth. 

Astronauts who can not bring themselves to swallow the toothpaste, or who have brought their own favorite brands, sometimes spit into a washcloth.

Using the Toilet

Since there is no gravity to either hold a toilet bowl full of water in place or pull human wastes down, designing a toilet for zero-gravity was no easy task. NASA had to use air flow to direct urine and feces. 

The toilets on the International Space Station are designed to look and feel as similar to those on Earth as possible. However, there are some important differences. Astronauts must use straps to hold their feet against the floor and pivoting bars swing across the thighs, ensuring the user remains seated. Since the system operates on a vacuum, a tight seal is essential.

Beside from the main toilet bowl, there is a hose, which is utilized as a urinal by men and women. It can be used in a standing position or can be attached to the commode by a pivoting mounting bracket for use in a sitting position. A separate receptacle allows for disposal of wipes. All units use flowing air instead of water to move waste through the system.

The human waste is separated and solid wastes are compressed, exposed to vacuum, and stored for later removal. Waste water is vented to space, although future systems may recycle it. The air is filtered to remove odor and bacteria and then returned to the station.

Future waste-removal systems on long-term missions may involve recycling for onboard hydroponics and gardens systems, or other recycling requirements. Space bathrooms have come a long way from the early days, when astronauts had pretty crude methods to handle the situation.

Edited and updated by Carolyn Collins Petersen.