Fearing that undersea communications cables were vulnerable to disruption, in 1963 the U.S. Air Force scattered 400 million tiny, needlelike strands of copper wire into orbit. These needles formed a loose belt around the Earth, creating a surface that long-range radio signals could reliably bounce off. They were supposed to burn up in the atmosphere within a few years, but many clumped together and are still orbiting the Earth today.