There's no way you can use water to collect waste in zero gravity. So, basically, our toilet on shuttle operations is a vacuum cleaner. The urinal looks like a Shop-Vac hose. It has different-shaped fronts on it for males and females to use. The urine is sucked down that hose and goes into a tank.

After the urine is collected over a couple of days, it's dumped into space, which is beautiful to watch because the urine freezes into a glitter of ice crystals shimmering in the sun.

The solid waste is returned to Earth with the shuttle. If we [astronauts] ever dump solid waste overboard, it's going to give new meaning to wishing upon a falling star.

In the space shuttle program, where we had males and females, I can tell you that nobody was doing that [sex] because there's absolutely no privacy. The only privacy would have been in the air lock, but everybody would know what you were doing. You're not out there doing a spacewalk. There's no reason to be in there.

If you look at astronauts closely, their eyes look kind of puffy. And it gives you this mild headache. But one of the advantages of that, if you will.

The opening for solid waste is very small [in the space ship]. It's not toilet-bowl size. And aim is critical. To be honest with you, you don't know where your asshole is pointing within a small circumference.

In weightlessness, one of the physiological changes is a fluid shift. Your blood and fluid is equally distributed in your body. So that makes your calves and thighs and waist skinnier, and it makes your chest and women's breasts broader. The downside is your face is kind of puffy