backstory

To give the boy a purpose/reason for going to moon i needed to come up with somekinda backstory which im hoping will show thro pictures of him and dad (? - who will be an astronaut when these are painted over) recieving his space medal and that medal will be the boy's prized possession which is missing and he is convinved its on the moon and travels to explore and retrieve by jumping in his cardboard box rocket and warping. 
Looked at various nasa medals and i dont think it needs to be named just a clearly engraved space theamed medallion hangin near pictures and clippings he's collect and pinned to wall of various missions etc, signed photos of other astronauts etc.... Im debating killing off the older character and showing that thro a headline on a news clipping which will add weight to the importance of finding the medal