Low-Earth orbit—roughly, anything that’s whizzing around the planet no more than 1,200 miles high—is the zone where SpaceX and many other New Space firms seek to operate. And simple math—together with the history of virtually all new forms of transportation—tells us that the more things go up there, and without a clear fix on where objects are in space, the greater the odds are that those things are going to start slamming into one another by accident.
One particularly grim vision of the future that haunts astronomers is the “Kessler syndrome,” proposed by the astrophysicist Donald Kessler in 1978. Kessler hypothesized that space clutter could reach a tipping point: One really bad collision could produce so much junk that it would trigger a chain reaction of collisions. This disaster scenario would leave hundreds of satellites eventually destroyed, and create a ring of debris that would make launching any new satellites impossible, forever.
The other point of discussion is the moon. At the moment, this is all remarkably unregulated. The issue with this is that the path for such exploration is often set early on.