A good-sized area of outer space, surrounding our planet, has become a virtual junkyard of debris that’s been accumulating since the beginning of the Space Age in the late 1950’s.
Today, the amount of space debris is estimated to be in the tens of millions, ranging from spent rocket stages, old andnon-functioning satellites, to tiny particles of rubble, all the result of collisions or simple erosion of spacecraft that have been up in space, some of them for decades.
The incident last week isn’t the first time astronauts have been threatened by space junk; the ISS had two other close calls last year.
Usually the space station performs what NASA calls a “debris avoidance maneuver” and simply moves itself slightly out of harm’s way.
The ISS might be having more space junk encounters sincechanging position in the last year, moving into an area with a slightly higher density of orbital debris.
Avoiding and protecting the space station from debris is a problem that requires vigilance from ISS support teams on Earth. It’s also a problem that isn’t going away any time soon.
Gene Stansbery, the office’s program manager, says even the smallest fragments of orbital debris can be harmful to spacecraft in orbit around the Earth – such as the ISS and communications and weather satelliteswe depend on.
Even the tiniest pieces of space trash are dangerous, in part because they’re moving at tremendous speeds, at a velocity of 11 kilometers per second. Early in the space shuttle program, during the STS-7 mission, a tiny paint fleck hurtling through space hit a shuttle window, causing so much damage the entire window had to be replaced.
NASA’s Orbital Debris Program office isn’t the only US agency keeping an eye on wayward space junk. The US Department of Defense, according to Stansbery, has a worldwide network that can track objects, in low Earth orbit, as small as 10 centimeters in size.
Some of space junk has returned to Earth, but it could take decades or even centuries, for other pieces of space debris to do the same. And, predicting just where it will land, is difficult, if not impossible to do.
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