A couple of questions:

1. How likely is it that a collision like this (two large satellites, high enough for the fragments to have a long orbital lifetime) occurs in any given year?

2. This announcement popped up on HN a couple of days before the event. Are we not able to project potential collisions farther ahead? I would think objects of this size are well tracked.

I'm wondering how difficult it would be to detect these far enough in advance to send something up to nudge one of the dead satellites out of the way.