The Smurfs #7: The Astrosmurf (Smurfs Graphic Novels)

When one of the Smurfs wants to travel to outer space, he tries to build a rocketship, but it fails to get off the ground and he grows depressed.  Papa Smurf and the other Smurfs make a plan in order to cheer him up: putting him to sleep and waking him up in an elaborately staged “planet” filled by other Smurfs pretending to be aliens!