Gravity plays a huge role in our ability to poop and bathe ourselves, but people living on Earth’s surface probably take this assistance for granted. Not NASA astronauts who live on the International Space Station — they have to learn to relieve and clean themselves in an environment with different physics. Here’s how they do it.

Going to the bathroom

The most daunting task on the ISS might be using the toilet. Instead of running water, it relies on suction. The astronauts pee into a hose that carries away their urine, and when they have to poop there is a seat that sucks in excrement and puts it into a bag. According to NASA’s Suni Williams, the seat is small so if your aim is not great, it’s possible to make a mess. And Chris Hadfield explained there’s a seatbelt to keep you centered on the toilet.

“Sometimes things get a little out of control if you are out of control yourself, flying around,” Williams said.

For cleaning up, there are wipes. She reviewed the different ones available and said the Russian wipes are “a little bit coarse.”

When the business is finished, the urine and feces are freeze-dried in space to kill bacteria and then ejected to burn up in Earth’s atmosphere, Hadfield said. “So the next time you see a beautiful shooting star going across the sky, that’s what it might be.”

Astronauts can be as apprehensive about the situation as you would be. In an interview earlier this year, before he launched on a Russian Soyuz spacecraft to the ISS, NASA’s Jack Fischer said he was most concerned about navigating the toilet aboard the station. Fischer was up there for four months, returning home to Earth late this summer.

“It’s all about suction, it’s really difficult, and I’m a bit terrified,” Fischer had said. “Unlike most things, you just can’t train for that on the ground — so I approach my space-toilet activities with respect, preparation, and a healthy dose of sheer terror.”

Taking a bath

There is no running water on the ISS, so there is no such thing as a space shower. But astronauts living in orbit around the Earth exercise every day and have to clean themselves. Astronaut Mike Fossum demonstrated the process in a NASA video (without nudity, you perverts!), adding soapy water to a wash cloth and rubbing it on his face.

Cleaning your hair

A soapy towel alone won’t cut it on your long locks, so ISS residents have a different process for their hair. Some female astronauts crop their hair but others, like Karen Nyberg, keep it long. She showed curious space enthusiasts how it’s done, explaining that her tools are water, no-rinse shampoo, a washcloth and a comb. She starts by wetting her scalp and using her hands to spread the water into the rest of her hair, then does the same with the shampoo with the help of the comb and washcloth. Then she does another round of water.

“As my hair dries, as the water evaporates from my hair, it will become humidity in the air and our air conditioning system will collect that,” Nyberg said, “and our water processing system will turn that into drinking water.”

Getting a haircut

Being in microgravity doesn’t make hair stop growing. If an astronaut takes a long stay on the International Space Station, he or she might have to get a little trim. That can create a problem though, because the hair would not fall straight to the ground, and loose hairs could get into places they should not. Flight engineer Chris Cassidy, who was on the ISS a few years ago, explained as he shaved his head in a video for NASA that the buzzer aboard the station hooks up to a hose that sucks up the disconnected hairs. But at a couple of points in his shave, he had to use the hose manually to direct the hose and catch everything that was coming off his head.