The moon is half styrofoam and half chocolate cake with buttercream icing. I cut an 8" styrofoam ball in half, glued it to the cake board, covered in plastic wrap and attached a half ball cake (baked in pyrex glass dish) to the top, iced the whole thing in buttercream. Buzz is a toy and the flag is paper. I made the "7" from gumpaste.
The mini cupcakes are chocolate and are coated with green-tinted white chocolate with fondant accents (eyes, ears, mouth).
Thanks for the info on CC on how to make a sphere cake!