PS Something to consider is the number of free spaceships out there already. In order to sell, IMO objects need to be kickass, and offer features not available with freebies. You'd probably need to do a whole collection of stuff that fitted together in various ways, along with ship interiors and planets and all sorts, to give people the idea that they can build whole 'worlds' like they're used to seeing in games. Expectations are very high, because game-graphics are so fantastic now.