Failures in the aerospace industry are usually spectacular, if not tragic and last weeks historic collision between two intact satellites, previous collisions have involved only a single satellite a much smaller pieces of space junk to my knowledge. On Tuesday (10 Feb 2009) the operational US Iridium 33 and defunct Russian Cosmos 2251 communications satellites collided at approximately 1656 GMT. The closing speed between the two satellites was estimated at approximately 15,000 mph.
That's one serious amount of speed if I think about what I have seen happen to vehicles when they collide at a couple of hundred km/h down here on earth. Needless to say the satellites were completely destroyed which in turn resulted in additional space junk orbiting the earth at extremely high velocities (the defunct Cosmos satellite was junk to start with).
I am not sure I would have wanted to be one of the three astronauts on the International Space Station this week despite the only minimal increase in risk of a debris collision estimated by the experts; probably the same guys who were supposed to be tracking the orbiting junk in the first place. In fairness scientist have been raising concern about the increasing number man made space junk in orbit around the earth and the increasing complexity in keeping track of it for many years now.
Its sad to think that we are not only polluting our world but the pristine space around it.