ISS Crew May Be Forced to Take Shelter from Space Debris

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Nov. 23 update: NASA reports that flight controllers have downgraded conjunction threat, and there is now no need for the crew to shelter in place on the space station.

What a fine welcome for the new crew on board the ISS: The three astronauts/cosmonauts on the space station may have to take shelter in their Soyuz spacecraft early Wednesday morning (Nov. 23), due to a close flyby or even a possible collision with a piece of space debris. Mission Control called up to the Expedition 30 at 2:06 pm EST today (Nov. 22), saying it was too late to do a debris avoidance maneuver with the entire station, and the crew should be ready to “shelter in place” in the Soyuz vehicle.

Reports are that the object is a piece of debris about 4 inches (10 centimeters) in diameter from the Chinese Fengyun 1C weather satellite that was destroyed in 2007. Current tracking indicates the object may come within 850 meters (2,800 feet) of the station.

An approach of debris is considered close only when it enters an imaginary “pizza box” shaped region around the station, measuring 0.75 kilometers above and below the station and 25 kilometers on each side (2,460 feet above and below and 15.6 by 15.6 miles). The undocking of the Expedition 29 crew yesterday altered the orbit of the ISS enough so that this object –which had previously not been a threat – is now on its way for a very close pass with the station.

Commander Dan Burbank and Flight Engineers Anton Shkaplerov and Anatoly Ivanishin will awake early and confer with Mission Control on the latest tracking data of the object, and decide by 4:30 a.m. EST (0930 UTC) on Nov. 23 if they should take shelter in the Soyuz.

NASA’s Chief Scientist for Orbital Debris Nicholas Johnson told Universe Today during a previous close conjunction of space debris and the ISS that on average, close approaches to ISS occur about three times a month.

Johnson said that small pieces of debris have already collided with ISS on many occasions, but these debris to date have not affected the safety of the crew or the operation of the mission. “The dedicated debris shields on ISS can withstand particles as large as 1 cm in diameter,” he said.

The crew has taken shelter in the Soyuz vehicles only twice during the 11 years of continual human presence on the ISS.