Astronaut explains how restrooms work in space

Forget all the scientific advances, the most popular question asked of astronauts is much more primal: How do you use the restroom?

Suction is needed to counteract the lack of gravity, and it's not much more complicated than that, according to European Space Agency's Tim Peake. The British space traveler this week laid it out for us in plain terms while holding up the pipe he calls a toilet.

"Take the cap off, turn on the fan, and the air flow keeps everything going down the pipe," he said, "simple as that."

Peake just joined the International Space Station team last month, so he's been sharing what he learns as he gets into the swing of doing flips in space, taking photos of Earth and yes, using the toilet.

If you're wondering how the astronauts are able to use a toilet that is shaped so differently, take a look at NASA's "training" space toilet. There's a camera inside, NASA explained, to help the astronauts practice "alignment." (We'll let you figure that one out.)

And because there's no such thing as "too much information" when it comes to the mysteries of space, we also know about what happens after the astronauts take care of business. As Samantha Cristoforetti of the ESA explained last year, the urine gets turned into drinking water.