November 23, 2011
UPDATE: Space Debris Found To Be No Threat To Station Crew
Flight Director Brian Smith called off planning to shelter the Expedition 30 crew in their Soyuz spacecraft after flight controllers evaluated tracking data on the Fengyun 1C satellite debris and concluded it poses no threat to the International Space Station. Consideration was given for sheltering the crew in their Soyuz TMA-22 spacecraft after initial tracking information indicated a high probability of the debris colliding with the station. But further tracking data confirmed that the debris poses no threat to the station or the crew. Commander Dan Burbank and Flight Engineers Anton Shkaplerov and Anatoly Ivanishin, who were informed Tuesday of the possibility they would have to shelter in their Soyuz craft, will be told when they wake up around 1 a.m. EST Wednesday that no such sheltering will be required.
Initial predictions indicated the object would have come within 2,800 feet (850 meters) of the station at 4:43 a.m. Wednesday. Had tracking continued to show the closest approach within a predetermined “pizza box” around the station, the crew would have been directed to take precautions that include closing hatches between station modules and getting into their Soyuz spacecraft.
Standard procedure for such encounters is to maneuver the space station out of the way of the predicted path of the debris if there is enough time to coordinate the move. However, preparations for yesterday´s undocking of the Soyuz spacecraft bringing Mike Fossum, Satoshi Furukawa and Sergei Volkov home slightly changed the station´s orbit, resulting in a closer approach. The object had been monitored earlier but was not then a threat.
The next International Space Station Update on NASA Television is scheduled for 11 a.m. Wednesday.
NASA said on Tuesday that Mission Control notified the Expedition 30 crew aboard the International Space Station of a potential collision with space debris.
The space agency said that the crew may have to take shelter early on Wednesday as a 4-inch piece of debris from the destroyed Chinese Fengyun 1C weather satellite is heading towards it.
NASA said that object may come within 2,800 feet of the station. Tracking shows that the space junk could float within a "pizza box" of the ISS.
It warned that the crew will be directed to take precautions that include closing hatches between station modules and getting into their Soyuz spacecraft about 30 minutes before the time of closest approach, which is no later than 4:30 a.m.
Standard procedure for these encounters is to maneuver the space station out of the way of the predicted path of the debris if there is enough time to coordinate the move.
The space agency said Mission Control will continue to monitor the object, and will inform the crew whether it will need to take shelter.
It said NASA will also advise ISS crew members to take precaution to either move away from an object or take shelter if the chance of a collision with debris exceeds 1 in 10,000.
Space debris can move about 22,000 feet per second when in orbit, and collisions "with even a small piece of debris will involve considerable energy," according to NASA.
There is about 19,000 objects larger than 4-inches known to be orbiting around earth. NASA said that a population of about 500,000 pieces of debris smaller than 4-inches is floating around in Earth's orbit.
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