It's a delicate question that's been challenging NASA: How can an astronaut relieve themselves in comfort while wearing a spacesuit.
If you're in flight at zero gravity, modern space craft are pretty well equipped in the toilet department. But matters get a lot more complicated when you have to put on your spacesuit; say for a space walk, when re-entering the Earth's atmosphere, or if there's some kind of emergency.
Currently the best solution is to wear a nappy, which is hardly ideal when you might be wearing one for days on end.
NASA launched its 'Space Poop Challenge' to find a better answer.
New Zealander Hugh McCarroll from Hamilton was a semifinalist. But the ultimate victor was Thatcher Cardon, a US Air Force Officer and doctor who used techniques employed in laparoscopic surgery to design an inflatable bed pan that could be inserted and removed from a spacesuit using a valve and plastic tube.