One of my first jobs in high school was working at the gift shop in the U.S. Space & Rocket Center in Huntsville AL. I hated my uniform but I loved learning about space travel, especially the daily lives of the astronauts. In the early days of the Gemini project, you would be stuck in what amounts to the front seat of the car for several days. In the shuttle, you at least had some room to maneuver, but what did you do all day when you weren’t doing science stuff? And what if we ever send people to Mars? That’s a three year trip in a cramped cabin. Sure, lots of people think about the bravery and heroism of astronauts. But I wanted to know how bad they smelled after a week wearing the same space suit. And how did they go to the bathroom in space? Or wash their hair? And why was their food so gross?

Mary Roach knows. In Packing for Mars, she goes on board with space monkeys, watches video of austronaut auditions, reads archives of isolation experiments and studies of what happens when you put three people in a small room for a week and don’t let them change their clothes. She eats meals designed by veterinarians for minimal excretory output. And yes, she visits the center where astronauts train to use the space-commode.

As with Stiff and Bonk, her earlier books about death and sex, Roach answers questions most of us aren’t quite brave enough to ask. The story is a combination of amazing, hilarious, and amazingly hilarious. The chapter on space bathroom technology alone is worth the price of admission.