Space junk is a problem

This was brought up in our Kurzweil discussion with a response that it's not a problem because space is so big. Well, the orbit around the earth is not that big and it's filling up with a our junk. It's such a problem that NASA even tracks the larger pieces of junk to avoid collisions with the space station and other space missions. But there's also thousands of pieces of other junk that is not being tracked. So what tech is going to solve that problem? It doesn't exist yet. A techno-optimist is sure that we'll figure out something like nanobots that eat metal, while in the meantime we keep accumulating more dangerous space junk.