NASA is tracking a large piece of space junk that could cross the path of the ISS.  Atlantis, on its final mission has just docked with the station.

On June 28th space debris narrowly missed the ISS in a rare incident that forced the crew into their Soyuz rescue craft.

A spacewalk is scheduled for tomorrow.  No word yet on whether a collision is imminent or if the station will alter it's orbit to avoid the junk.