ISS astronauts were ordered into the space version of an emergency lifeboat last Friday when Mission Control identified an old piece of a Russian communications satellite was projected to come close to the space station. Normal procedure calls for the ISS itself to take evasive maneuvers, but the threat was spotted too late in this case to plot a move.
The six ISS astronauts took cover in two docked Soyuz space capsules during the critical window in case escape was called for. Fortunately for the crew, the debris passed by an estimated six to nine miles from the space station without incident.
The debris was the result of the Russian Cosmos 2251 communications satellite crashing into U.S. satellite Iridium 33 in 2009, which created a massive cloud of space junk. Even though NASA and its international counterparts believed the space trash to be relatively small threat, because the exact size of the debris couldn't be pinned down they took a conservative approach.
The move into escape vehicles was only the third time in 12 years that ISS crew took shelter in a near miss. Avoidance orders are usually the norm, but moving the station usually occurs when there are several days notice.
Given that there is an estimated 6,000 tons of debris in orbit, despite the close call it was a happy ending in this case. NASA and the military's Space Surveillance Network monitor approximately 20,000 pieces of space trash so that the ISS and other active pieces of space equipment have advance warning to move out of the way.
The problem of space trash is such a growing issue that the U.S. has backed the EU's Code of Conduct on space debris. The Code aims at ensuring future space efforts are sustainable and safe.
Perhaps even more practically, various space agencies and private firms are looking at ever unique ways of cleaning up the significant amount of waste in already in orbit. From floating garbage scows to lasers, the hope is to get a handle on the space waste before something more serious than a near miss happens.