From spaceflightnow:
http://www.spaceflightnow.com/shuttle/sts119/090316fd2/
Flight controllers at the Johnson Space Center in Houston, meanwhile, are continuing to evaluate the orbit of a piece of Russian space junk to determine if a space station debris avoidance maneuver might be necessary later today.
"Tracking data from government resources indicated a piece of a Cosmos spacecraft ... was going to pass within the (safety) threshold," said Pat Ryan in mission control. "Plans at that point were begun for a possible debris avoidance maneuver, an engine burn by the international space station that would move it so that it was well clear of this piece of space junk."
A more recent update indicated "there is now no threshold violation anticipated by this piece of space junk," Ryan said. "But because the target has seemed to be a moving one, the station teams are proceeding with their plans to be ready with a debris avoidance maneuver tonight and they are content to wait until at least the next round of tracking data ... before coming to a final decision."
If a debris avoidance maneuver is required, a rocket firing would be targeted for around 9:50 p.m., Ryan said. The debris, from the Russian Cosmos 1275 military navigation satellite launched in 1981, is expected to make its closest approach to the station around 3:14 a.m. Tuesday. But it was not immediately known how big the debris might be or how close it might come to the station.
Shuttle flight planners are preparing to make changes to Discovery's rendezvous rocket firing sequence to accommodate any move by the space station if an avoidance maneuver is, in fact, ordered.