Cosmic by Frank Cottrell Boyce

Liam has always felt a bit like he’s stuck between two worlds.  This
is primarily due to the fact that 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.

Listen to a clip of the Cosmic Audio Book here.