The June 2006 issue of Scientific American posted an article on page 26 titled: Data Points: Girdled by Garbage.
"Discarded rockets, exploded satellites, paint flecks and even human waste contribute to the earth's orbital litter." Our space trash is hazardous to space travelers: "Even if humans stopped launching satellites now, debris will increase after 2055" because bits broken from larger pieces will increase the total quantity and will "exceed the rate of destruction by reentry burn-up."
"Percentage of orbital objects that are debris: 93
Number of fragments at least 10 centimeters wide: 9,000
Combined mass, in kilograms: 5 million
Number of known orbital collisions, 1991-2005: 3
Number of collisions expected in the next 200 years: 18
Number of collisions expected to be catastrophic: 11"
Stated source for information: U.S. Strategic Command Science, January 20, 2006.
Sounds like NASA needs some scavenger robos.
Cleaning up space junk
NASA photo: Ed White Space Walk