See Inside Space Stations and Other Spacecraft
My son loves this book, he loves non-fiction books and this one is definitely not short on facts. The great thing is each flap has a new fact which is no more than a line!
For his age (6yrs) it is perfect as it is within his reading ability so he can read it by himself and delight in teaching me new things. Space was one of the topics he covered this term in school and he was very excited to bring this book in for show and tell.
His favourite part of this book was the section on how to build a spaceship.