I'm not having much luck getting updated info on space junk. The websites I looked at had nothing later than 2004 articles. But I finally found this comment at:
http://nasaexplores.nasa.gov/show2_5...d=04-072&gl=58 Quote:
| Since the smallest pieces of debris cannot be tracked, collisions with them [spacecraft] are bound to happen. The Space Shuttle often returns to Earth with tiny impact craters. And, impacts can even create small cracks in the front windows! Even though the spacecraft run into this debris quite often, the debris rarely runs into other debris. If fact, we only know of one time where this actually happened! |
Note: Brackets above are mine - I didn't want to quote the previous paragraphs that made this clear.
So, apparently the idea of junk running into other junk and thus creating more discrete pieces of junk is not a significant factor.