Orbital debris, or “space junk,” is any man-made object in orbit around the Earth that no longer serves a useful purpose. To minimize the risk of collision between spacecraft and space junk, the U.S. Space Surveillance Network tracks all debris larger than 10 centimeters. These images represent all man-made objects, both functioning and useful objects and debris, currently being tracked. Though the black dots that represent objects in space swarm around the Earth, obscuring the surface in the lower image, the space junk situation is not as dire as it may appear. The dots are not to scale, and space is a very big place. Collisions between large objects are fairly rare. The orbit of each piece is well known. If any debris comes into the path of an operating NASA satellite, flight controllers will maneuver the satellite out of harm’s way. From NASA's Earth Observatory.