Because of the lack of gravity, going to the toilet in space can be a tricky operation. Toilets on board space stations are equipped with restraints to hold an astronaut in place. A powerful vacuum pump is used to create a seal between the body and the seat. Waste products are collected. Some are recycled, while solid waste is disposed of safely.
Each spacecraft comes equipped with a unisex toilet. Although the toilet itself looks like a slightly higher-tech version of its counterparts here on Earth, it’s designed a bit differently. The toilet consists of a commode that holds solid wastes and a urinal for liquid wastes. A funnel that fits over the genital area allows both men and women 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 waste also doesn’t float around, the toilet uses flowing air instead of water to flush the toilet. The air 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. Solid wastes are dried to remove all moisture, compressed and kept in an on-board storage container. They’re removed and disposed of once the spacecraft has landed. The liquid waste is sent into space.
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 goes to the bathroom, 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.