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.

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.

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.

And you're headed to a place with no bath and no shower. So you can just imagine how crazy it is to get up there, take your diaper off, have a urine-soaked crotch, and all you can do is wet a washcloth and wipe your skin off. You also have to do it on landing and spacewalks, too. It's not a ride that makes you springtime fresh.

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.

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.

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