Space debris refers to the remnants of old satellites, spent rocket stages, and other fragments left in orbit around the Earth. As more missions are launched into space, the amount of debris increases, posing risks to operational spacecraft and the International Space Station (ISS). This debris travels at high speeds, making even small pieces potentially dangerous. Organizations like NASA and ESA monitor space debris to track its location and predict potential collisions, helping to ensure the safety of astronauts and equipment in space.