Tommy loved playing in the gravity wheel. He wasn't supposed to. Nor was he supposed to love it as much as he did, but he did. To the point he didn't like wearing his mag-shoes.
He just preferred to float about and fly.
That was where the fun was.
Even if he was just a little worried about Napoleon floating away sometimes. Maybe not worried, but concerned.
Logically, he knew the dog wouldn't float away, the airlock wasn't open. But it nagged at him sometimes.
Napoleon barked from the other side of the wheel.
Tommy looked over.
Life was good.
Tommy and Napoleon are the only named characters in this scene. There's also Tommy's mother and Tommy's father - the son of the narrators. So that makes Tommy the grandson of the narrators.
I do wonder though, whether Tommy was born in space, or if he was brought up there by his parents.