DAVE LEFLAR, BARRINGTON, ILLINOIS: Hi, my name is Dave Leflar from Barrington, Illinois. And my question for CNN is: How much waste does NASA leave in space in a year?</s>MILES O'BRIEN, CNN SPACE CORRESPONDENT: Dave, NASA is not much of a litterbug in space. As a matter of fact, the people who keep track of orbital debris at NASA and at Space Command -- the folks who keep track of all things that orbit the planet -- tell me that NASA's amount of waste that it leaves behind is negligible. It really can't even be measured. Occasionally, during a space walk, a spacewalker will lose control of a bolt or a tool or a piece of the space station. And those pieces might stay in orbit for some time before they eventually decay and reenter the atmosphere. But as far as the shuttle goes, there's not a single piece that it leaves behind in orbit. And the space station itself, it generates waste, of course. But all the waste that is generated on there is sealed up and returned to Earth, either in a shuttle or in an unmanned Russian freighter. So, as it turns out, the space agencies are very sensitive to this idea of leaving waste behind in orbit.
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