More than 500,000 pieces of debris, or “space junk,” are tracked as they orbit the Earth. They all travel at speeds up to 17,500 mph, fast enough for a relatively small piece of orbital debris to damage a satellite or a spacecraft. If that sounds dangerous, that’s because it it is. The rising population of space debris increases the potential danger to all space vehicles, but especially to the International Space Station, space shuttles and manned spacecraft. NASA takes the threat of collisions with space debris seriously and has a long-standing set of guidelines on how to deal with each potential collision threat.