So the fine point on mining or colonisation is whether it is a territorial claim or a development claim. If you can get up there and colonise or mine, then pretty much you are entitled to claim what you are actually colonising or mining, as a developmental claim. As a territorial claim it should of course be banned, you can not point to the sky and claim to own it all because you have lots of nuclear war heads. It might seem odd compared to claims on earth but in all seriousness it will most likely suffice for the next hundred years or so and we should be doing all we can to promote the space race over stupendously destructive earth bound wars for profits and egos. There is a whole galaxy out there waiting to be explored, experienced and enjoyed.