The dying satellite that may hit Earth next month is just the start of it. There are thousands of pieces of man-made debris in orbit up there.
Space.com says that the U.S. Space Command monitors space debris and other objects, reporting directly to NASA and other agencies whenever there's threat of an orbital impact. The
NASA Orbital Debris Program Office, located at the Johnson Space Center, is the lead NASA center for orbital debris research.
NASA has
computer-generated graphics of the objects it is tracking that surround the planet. NASA says:
Approximately 95 percent of the objects in this illustration are orbital debris, i.e., not functional satellites. The dots represent the current location of each item. The orbital debris dots are scaled according to the image size of the graphic to optimize their visibility and are not scaled to Earth. These images provide a good visualization of where the greatest orbital debris populations exist. Below are the graphics generated from different observation points.
2007 was the worst year ever for space debris. Look at this chart to see the huge jump in the amount of stuff floating around out there. (Click on the chart for a larger view.)
The U.S. and the former Soviet Union were once responsible for most of the debris floating in space. But now, according to the
January 2008 issue of Space Debris Quarterly Newsletter [PDF], China is the leading contributor, accounting for 42 percent of space debris, compared to 27.5 percent sent up by the U.S. and 25.5 percent from Russia.
In 2007, the Chinese used a missile to test whether they could shoot a satellite out of the sky. The test sent 2,317 pieces of debris into Earth's orbit, according to the newsletter.
Here is some more information on the Orbital Debris Program's work:
Sometimes the junk does hit Earth.
NASA provides this photo of a steel tank that landed in Georgetown, Texas:
The BBC points out:Normally, when U.S. spy satellites reach the end of their lives, they are disposed of through a controlled re-entry and dumped in the Pacific Ocean, so that no one can learn their secrets.
- The oldest debris still in orbit is the second U.S. satellite, the Vanguard I, launched on March 17, 1958, which worked only for six years.
- In 1965, during the first American space walk, the Gemini 4 astronaut Edward White lost a glove. For a month, the glove stayed in orbit with a speed of 28,000 kilometers per hour, becoming the most dangerous garment in history.
- More than 200 objects, most of them rubbish bags, were released by the Mir space station during its first 10 years of operation.
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The most space debris created by a spacecraft's destruction was due to the upper stage of a Pegasus rocket launched in 1994. Its explosion in 1996 generated a cloud of some 300,000 fragments bigger than 4 mm, and 700 among them were big enough to be catalogued. This explosion alone doubled the Hubble Space Telescope's collision risk.
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