WASHINGTON -- Heads up, space travelers.
Somewhere beyond the Earth's atmosphere, old paint chips, discarded satellites and yesterday's rocket separation devices may well come hurtling across your path.
As many as 70,000 bits of man-made debris may be orbiting Earth at velocities of up to 4 miles a second, according to a new congressional report, which warns that a mounting trash problem could hamper future space exploration activities.
"Continuing steady growth of orbital debris could, by 2000 or 2010, render some well-used low-Earth orbits too risky to use," said the Office of Technology Assessment report.
Collisions with such debris -- the byproducts of more than 3,200 space launches since Sputnik I in 1957 -- pose serious hazards for both spacecraft and human life, the study said. "Even very small objects, if they have high velocities relative to the objects they hit, may do considerable damage," it said.
One incident occurred in 1983, when a paint chip measuring about 0.2 millimeter in diameter collided with the Challenger space shuttle and badly damaged a window.
Currently, the Hubble Space Telescope faces a 1 in 100 chance of suffering severe damage from space debris during its planned 17-year lifetime, according to some projections.
The growing amounts of space litter may be equally hazardous to earthlings.
During the past three decades, about 14,000 objects have fallen to Earth, and similar debris continues to re-enter the atmosphere at a rate of two to three a day, the study said. A 7-foot strip of metal from a Soviet rocket landed in Lakeport, Calif., in 1987, and the nuclear-powered satellite USSR Kosmos 954 scattered debris over northwest Canada when it re-entered the atmosphere in 1978.
Although the probability of losses to life or property are currently small, the study predicted that -- if left unchecked -- space debris will be an increasingly troublesome problem.
"It's like all pollution problems -- it starts small and builds up over time," said OTA senior associate Ray Williamson, who directed the study.
The removal of existing debris is currently not cost-effective, the study said, but it called for further development of spacecraft and launch vehicles that would be less likely to explode or break up in space.
All nations also must be encouraged to cooperate on the orbital debris problem, said the report, which notes that a new international treaty specifically addressing the issue may need to be implemented.