Packing for Mars: The Curious Science of Life in the Void by Mary Roach is a nonfiction analysis of what NASA's work on getting to Mars. What we know and what we need to find out.
Sounds boring, right?
It's surprisingly not. Mary Roach has a talent for picking up the weird minutiae and pulling a whole chapter out of it. Like: how do you shit in space? stay clean? eat? at what point do you reach your BO threshold and when does your skin stop accumulating oil. Is that story about Enos the chimpanzee being the first thing to orgasm in space even true? ( spoiler alert: it's not...probably)
I'm definitely going to read her other books: Spook: Science Tackles the Afterlife, Stiff: the Curious Lives of Human Cadavers, and Bonk: The Curious Coupling of Science and Sex
By the way, they're using cadavers for crash test dummies now. I'm trying not to judge based on my initial reaction, but I'd be freaked out.
Anyway, I'm always hesitant about recommending nonfiction books, but if you once in your life had an interest in space you'll probably enjoy this one.