Cosmic by Frank Cottrell-Boyce

Liam has always felt a bit like he's stuck between two worlds. This is primarily because he's a twelve-year-old kid who looks like he's about thirty. Sometimes it's not so bad, like when his new principal mistakes him for a teacher on the first day of school or when he convinces a car dealer to let him take a Porsche out on a test drive. But mostly it's just frustrating, being a kid trapped in an adult world. And so he decides to flip things around. Liam cons his way onto the first spaceship to take civilians into space, a special flight for a group of kids and an adult chaperone, and he is going as the adult chaperone. It's not long before Liam, along with his friends, is stuck between two worlds again--only this time he's 239,000 miles from home.
Frank Cottrell Boyce brings us a funny and touching story of the many ways in which grown-upness is truly wasted on grown-ups.