Space Debris Threatens Space Station

 
 
By Roy Mark  |  Posted 2009-11-06
 
 
 

NASA informed the crew of the International Space Station Nov. 6 that the spacecraft could be menaced by a piece of Russian Cosmos space debris. The time of closest approach is 10:48 p.m. EST.

NASA said the timing of available tracking data has made it too late to do a maneuver, but better tracking data will be available later on Nov. 6. When the data becomes available, the option of having the crew sleep in the Soyuz module will be discussed.

Mission Control Center in Houston contacted ISS Commander Frank De Winne at 10:04 a.m. informing him of the possible hit and NASA's effort to more accurately determine the path of the orbiting debris.

Spacecraft communicator Jason Hutt told De Winne, "We are possibly going to get one more data point on this conjunction." He then added, "We are going to have to make a decision [as to] what we're going to have to do with regards to getting in the Soyuz."

Avoiding space debris is becoming commonplace for the ISS. In March, with the space shuttle Discovery docked at the ISS, it was forced to change orbit to avoid being smacked by 10-year-old debris from a Chinese satellite launch. The maneuver was successful but marked the third time in three weeks the ISS had been threatened by space debris.

A breakaway piece of a Russian satellite came close enough to the ISS for NASA engineers March 17 to consider moving the space station and recalibrating Discovery's track to the ISS. The previous week, a piece of a Russian spacecraft motor came close enough to the ISS that the three-man crew was forced to evacuate to the Soyuz TMA-13 capsule, which is attached to the space station to transport astronauts back in an emergency.

The United States-operated SSN (Space Surveillance Network) tracks 17,300 artificial objects in space larger than 10 centimeters. About 800 of those objects are operational satellites. But the SSN tracks only a fraction of the junk orbiting Earth. The Secure World Foundation estimates that 300,000 objects are out there, the flotsam of a half-century of space exploration.

The debris includes discarded fuel tanks, screws, blots, paint chips, foil scraps and other objects. The Secure World Foundation estimates that there are also billions of bits and pieces smaller than 1 centimeter circling the planet, each following its own orbit. During an eight-year period ending in 2002, the Hubble Space Telescope's solar panels were struck 725,000 times, with approximately 5,000 of those impacts being large enough to be seen by the naked eye.

The ISS was designed with shielding to protect against impacts by debris ranging from 1 millimeter to 1 cm in size.

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