1) The Moon contains metals that can be used to make useful things. In the long run, it would be cheaper to make the parts for orbital colonies there, instead

1) The Moon contains metals that can be used to make useful things. In the long run, it would be cheaper to make the parts for orbital colonies there, instead of making them on Earth and boosting them into orbit. 2) There is evidence that there is water and oxygen on the Moon. Again, it is cheaper to collect these on the Moon and send them out to the orbital factories and space-based solar collectors than it would be to do so from Earth.