Earth's orbit is swarming with debris — meet the satellite designed to clean it up

At any given time, NASA is keeping track of about 16,000 pieces of space junk in Earth's orbit — and those are just the big chunks. This debris poses a serious safety hazard, primarily to operational satellites in the planet's orbit, but also to astronauts like those on board the ISS. In fact, according to some NASA… »2/17/12 4:50pm2/17/12 4:50pm