I remember hearing about the growing orbital debris problem awhile back and thinking, Well, we've covered the surface area of the earth with a whole ton of stuff, but when you fly in an airplane and look out, most of the surface still looks almost completely untouched. Now the "surface area" of the orbit is way bigger than the earth's surface area, and we don't have nearly as much stuff up there yet, either. So shouldn't it be a long time before we start having problems like this?
I suppose the big issue is that most of that stuff is moving. If everything on the surface of the earth was constantly trying to circumscribe it, we'd have a lot more stuff colliding than we already do...
Don't look at the surface, look at the sky. You hardly ever see another airplane except occasionally when near an airport.
And yet, mid-air collisions do happen, despite the systems in place to prevent them.
The fact that all of this stuff is moving makes it a completely different proposition. The fact that a collision just makes more junk to go out and collide with other stuff results in a potentially disastrous feedback loop.
Also, very few things up there are made to be durable in the face of collisions. That adds weight for, until recently, no apparent value. So even small pieces of debris are very dangerous to useful equipment.
I suppose the big issue is that most of that stuff is moving. If everything on the surface of the earth was constantly trying to circumscribe it, we'd have a lot more stuff colliding than we already do...