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.
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.
International cooperation in dealing with the growing problem or orbital debris is essential, a panel of experts argued, but said not to expect a comprehensive accord on the issue for the foreseeable future.