Space Debris

Space debris refers to defunct human-made objects in orbit around Earth, including spent rocket stages, dead satellites, and fragments produced by collisions, explosions and deliberate anti-satellite tests. Because objects in low Earth orbit travel at several kilometers per second, even a small fragment can cripple or destroy an operational spacecraft on impact, and the population of tracked debris has grown large enough to threaten a runaway cascade of further collisions, a scenario described by the Kessler syndrome. Tracking networks catalog tens of thousands of objects large enough to observe, while a far greater number of smaller untracked fragments also pose a hazard.