1. Which god are you talking about?
2. If we assume that you're talking about Christian God, then didn't he create the whole world? Including space???
Also your question implies that god is on earth. God isn't tho (as far as I know). And by that I don't mean he's on some other planet or anything, but I mean that he's just there existing.
Also 3. In "Heaven and earth", we can understand earth as a place humans live in/on. So if we go to Mars, he'll "be there" too.