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.

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.

NASA's training philosophy is "no surprises." So what they did is put a simulator on Earth where it looks exactly the same as a shuttle toilet and they put a camera down in the bottom of the opening for solid-waste collection, with a light that basically illuminates your asshole.

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.

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.

You can't put toilet paper in the toilet [in the space ship], so there's a separate vacuum can in front of you on the wall and when you're done, you put the toilet paper in there and seal that up.