Space is littered with millions of bits of orbiting garbage leftover from missions. The flying flotsam can delay launches and could potentially smash into spacecraft. Now some creative ideas are emerging for how to sweep up the junk.
Giant chunks of manmade space junk - like the dead satellite that the U.S. government shot down - regularly fall to Earth. Yet no one has ever been reported hurt by them. Chunks of debris weighing two tons or more from satellites and rocket parts fall uncontrolled every three weeks or so, according to an analysis by a Harvard University astronomer who tracks satellites and space debris.
The Chinese government is implementing a wide series of measures to reduce the amount of debris left in orbit by Chinese rockets and satellites, and to develop a space-surveillance tool to determine what is in orbit, Chinese space-debris experts said.
Scientists have concluded that a Chinese missile test in January that smashed an aging weather satellite was the messiest space event ever, adding more than 1,500 big scraps of debris to a junkyard that's orbiting the Earth.
Astronauts on the International Space Station have been hurling more garbage out the station's back door in recent months. Outdated equipment - some of it expensive - that's not practical for the space shuttle to bring back to Earth is simply being thrown into space.
China has joined other members of a United Nations technical subcommittee in approving draft guidelines for mitigating manmade space debris, after receiving "considerable criticism" for adding to the space-debris problem with its Jan. 11 anti-satellite (ASAT) weapon test.
Just over a month after a Chinese satellite was intentionally smashed into bits in a test of anti-satellite technology, a Russian rocket body exploded accidentally, littering the skies with more than 1000 additional pieces of space junk. The amount of space debris created is roughly on par with that released during China's test, which was considered the worst space debris event in the history of space launches. And experts say the debris is likely to stay in orbit for a long time, creating a danger to other spacecraft.
Human increases in carbon dioxide emissions are thinning the Earth's outer atmosphere, making it easier to keep the space station aloft but prolonging the life of dangerous space debris.
Outer space is fast filling up with human-generated junk, from exploded satellites to leaky nuclear reactors, and the debris threatens the safety of cosmic exploration.
In the last decade or so, as scientists came to agree that the number of objects in orbit had surpassed a critical mass - or, in their terms, the critical spatial density, the point at which a chain reaction becomes inevitable - they grew more anxious. Now, experts say, China's test on Jan. 11 of an antisatellite rocket that shattered an old satellite into hundreds of large fragments means the chain reaction will most likely start sooner. If their predictions are right, the cascade could put billions of dollars' worth of advanced satellites at risk and eventually threaten to limit humanity's reach for the stars.