What you are talking about here is VERY near Earth space, and I would agree that we do need to watch this area very heavily. But strangely enough what is really needed here are more human beings in LEO to actually help to not only not pollute more, but even to help clean up what is already there from former times when we were not so careful.<br /><br />For instance we could place some three large manned platforms at GEO then take up ALL the extra older satellites at that orbit. This would not only facilitate continued maintenance of that important orbital resource, but at the same time almost totally clean up the debris form what is already a very crowded area of space! <br /><br />However, once you get beyond the orbit of the moon it become alnost totally impossible for the limited resources of humanity to even begin to pollute space itself. And the other side of the moon, which can not even be seen from the Earth, is also an area the can be relatively exploited for its reources without actually harming it very much. As I stated earlier, you would need to have a very powerful telescope to even see the largest mines on the Earth if they were to be somehow transported to the visable lunar surface. <br /><br />By the time such mining could even become a pollution problem on the moon, asteriodal mining itself would have taken over, and humanity could then expand into space almost forever before this even bacame any kind of a problem (if ever). The materials all the way out into the ort cloud (a sphere almost an entire light year in diameter), are almot totally limitless. By the time we could even begin to exploit such materials we should be able to travel (in O.Niell type colonies if nothing else) to nearby stars. If we (as the results of SETi seem to indicate) are truly the only fully sentient life form in our nearby steller space, then the future can indeed be almost limitless without worrying about such pollution at all!!<br /><br />Of course, this all depends on whe