The book is even better than the (great) movie. The Mercury astronauts had to fight to get a window in the capsule and some amount of control over the attitude

The book is even better than the (great) movie. The Mercury astronauts had to fight to get a window in the capsule and some amount of control over the attitude jets. They didn't mind being expendable -- they were test pilots, after all -- but they didn't want NASA to forget that they were pilots, not passengers.