The Hubble servicing mission has been buzzed by debris left over from a 2007 Chinese anti-satellite weapon test. The debris flew within about 2.8 km of the space shuttle Atlantis, which is currently working to install new instruments and gyroscopes on the telescope.

As we noted some months ago, satellite debris is a very real risk for the Hubble servicing mission. The amount of debris in space has increased dramatically over the past few years—first because of the Chinese anti satellite test, and then due to the collision of two satellites in February. Most of that debris is well above the International Space Station, where the shuttle usually travels, but other pieces have entered similar orbits to that of Hubble, which is at a higher altitude.

Shuttle program managers had at first put the risk of a collision at 1 in 185, below the nominal 1 in 200 safety limit. After a more detailed analysis, Nasa’s orbital debris revised that downward to 1 in 229, although the portion of the mission that takes place at Hubble altitudes carries a somewhat higher risk.

Nasa is watching the situation carefully with both Air Force and Nasa tracking stations around the globe. They notified the crew that the 10 cm piece of debris would pass by at around 7:30 Eastern Time yesterday.

In this particular case, no evasive action was necessary, and the mission continues apace: astronauts are already undertaking the first spacewalk to rejuvenate the aging telescope (see right).

Image: Nasa