The amount of trash in Earth orbit, from spent rocket stages, broken satellites and micrometeoroids, is growing. Scientists are working on methods to combat the threat of space junk and orbital debris collisions.
Concerns about space junk and satellite-launch regulations are swirling after the Federal Communications Commission alleged that a U.S. company launched four tiny satellites without permission.
China's Tiangong-1 space lab is headed for an uncontrolled and destructive nose-dive into Earth's atmosphere early next year. But it's unclear exactly when and where the spacecraft will come down.