Tuesday, April 05, 2011

Station Crew Safe After Debris Alert

A small piece of space debris drifted dangerously close to the International Space Station today, prompting the crew to prepare to seek shelter in an outpost lifeboat. But the red alert was called off after the chunk of an exploded Chinese satellite passed safely by the complex.

Russian cosmonaut Dmitry Kondratyev, U.S. astronaut Catherine "Cady" Coleman and Italian astronaut Paulo Nespoli of the European Space Agency were told the object would pass within three miles of the station, and that there was not enough time to perform an evasive propulsive maneuver.

The fallback in that case was to prepare to board a Soyuz spacecraft parked at the station. But an all clear was called at 2:41 p.m. EDT.

"We called it off before they even started closing hatches," said Kelly Humphries, a spokesman for NASA's Johnson Space Center in Houston, home of the U.S. station Mission Control Center.

The standard evacuation drill calls for hatches between station modules to be closed and sealed before boarding Soyuz lifeboats. The action is taken to make certain any breach in the hull of a station module would not cause a depressurization throughout the entire complex.

The six-inch piece of debris came from a Chinese satellite that was deliberately destroyed in 2007 as part of a weapons test.

The incident followed a close call last Friday that resulted in a station maneuver done to avoid a collision with an piece of space junk generated when two satellites smashed into each other in 2009.

Micrometeorite and space debris is the No. 1 safety threat to the $100 billion station and its resident crews. Traveling faster than the speed of rifle bullets, dime-sized micrometeorites and debris could punch holes in the hulls of station modules, triggering deadly depressurization or potential station evacuation.

NASA safety studies show there is a 1 in 2 chance of losing the station if the outpost is left untended for a year.

The Air Force tracks more than 12,000 pieces of junk and alerts NASA when it detects debris that could threaten the station.

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