1 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 (miles per hour), fast enough for a relatively small piece of orbiting debris to damage a satellite or a spacecraft.2 The rising population of space debris increases the potential danger to all space vehicles, but especially to the International Space Station, space shuttles and other spacecrafts with humans on board.