Will astronauts ever be hit by orbiting debris?

Probably, although the Space Shuttle has already been hit by a large object a millimeter in size. In November, 1995 inspection of the cargo bay door showed a crater 2 centimeters long and 6 millimeters deep caused by a piece of electronic circuit board traveling at 5 kilometers per second. If the door had been open at the time of impact, the fragment would have hit oxygen tanks in the cargo bay, which would have exploded.

In 1998 we will begin the construction of the Space Station. A 'bumper' will be installed on the leading edge of the station to vaporize harmlessly any particles up to a centimeter in size. NASA's 'Haystack radar' has been monitoring radar signals from a small spot in the sky and has detected over 400,000 pieces of debris about 5 millimeters or larger passing over head. The US Space Command routinely tracks over 8000 objects 10 centimeters across or larger. It is expected that the Space Station will have a 1 percent risk per year of being hit, and holed, by a debris particle or meteor. In its 10 year lifetime, this is 1 chance in 10. Pretty bad odds. This does not include dozens of hits per month that are expected to be shielded by the 'bumper' system. I do not know if I would want to work in a room where there is a good chance that someone will fire a 'cosmic bullet' that would penetrate the walls and perhaps hit me, or cause a catastrophic leak before I could scramble into a spacesuit. You can be sure that the first time this happens, there will be a major Congressional investigation into who is at fault. 'the fault is not in ourselves but in the stars!". If you want more information, there is a NASA site that has a pretty good, illustrated document reviewing the problem of orbital debris for spacecraft.


Copyright 1997 Dr. Sten Odenwald
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