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Fearing Collisions in Space, U.S. Tracks Orbiting Debris : Science: With 7,000 pieces of 'junk' circling Earth, some say a disaster for manned craft is virtual certainty.


CHEYENNE MOUNTAIN, Colo. — Deep in the bowels of this Rocky Mountain granite fortress, in a windowless room full of color computers with large, round display screens, military men and women are working around the clock to prevent what many fear is the next lurking space disaster: a cataclysmic collision between a manned spacecraft and space debris.

The U.S. Space Surveillance Network, originally designed to serve as an early-warning system against missile attacks, now devotes much of its time and resources to tracking 7,000 chunks of orbiting space debris that increasingly threaten astronauts and spacecraft, including sensitive military intelligence-gathering satellites.

But with about 240 new pieces of junk to track each year--plus untold numbers of smaller but equally dangerous pieces of undetectable debris--some fear that catastrophe is only around the corner.

Fueled by such concern, space-faring nations are racing to develop new technologies to track debris before disaster strikes. There is even talk of sending Gargantuan balloons filled with foam to sweep up space junk, which range in size from paint flecks to nuts and bolts to huge chunks of rocket parts.

Otherwise, such debris "could render some well-used low-Earth orbits too risky to use" by the year 2000, the congressional Office of Technology Assessment warns.

"We could end up imprisoned on this planet by our own hands," adds John E. Pike, a leading private space analyst.

Given present conditions, "harmful collisions with spacecraft would be virtually ensured" in the next decade or two, predicts Ray A. Williamson, a space debris expert with the Office of Technology Assessment.

Such a catastrophic scenario was nearly played out twice this autumn when the Space Surveillance Network had to warn two consecutive space shuttle crews of impending danger, which was averted when the shuttles maneuvered out of harm's way.

During the first decade of the shuttle program, beginning in 1981, no orbiter had to dodge debris.

"Thirty years ago, you could go up there and drive around and not worry. But no more," says Pike, director for space policy at the Washington-based American Federation of Scientists. "Now the surveillance network is doing a brisk business, engaged in traffic management."

Debris is generated when spacecraft are released from the upper stages of rockets and when lens covers, clamps, astronaut gloves, cameras and other incidental hardware are jettisoned.

Some pieces of debris are downright massive, like the 3,200-pound Soviet rocket remnant that lurked in the path of Atlantis late last month.

But they are far outnumbered by some 70,000 much smaller but also potentially lethal objects that cannot now be detected, such as paint chips--"the most serious hazard to space operations," says Williamson.

"These tiny objects can wreak considerable havoc by scouring or contaminating sensitive surfaces and instruments," he notes. "They also may be capable of piercing current spacesuits of astronauts working outside their spacecraft."

"We just don't have a handle on that stuff at all," adds Pike.

Of the two dozen spacecraft that have unexpectedly broken apart, at least one has been linked to a collision with debris--the unmanned Soviet Cosmos 1275, which fragmented in 1981.

And a U.S. research satellite, Pageos 1, is listed as a "possible" collision victim. It broke apart in July, 1975, a decade after launch.

The most recent close encounter occurred during the flight of the Atlantis in November.

But after being warned by officials here, commander Frederick Gregory simply charted a new course. Otherwise the Atlantis would have been traveling a mere three miles behind the Cosmos booster.

"There will be more frequency of avoidance maneuvers--probably getting to where one is required once every other mission or so," a National Aeronautics and Space Administration scientist conceded after the mission.

The shuttle Discovery in mid-September also had to dodge a piece of debris.

In space, where everything travels at a speed of 17,000 m.p.h., even minuscule objects can cause considerable damage.

A chilling reminder of that occurred in 1983 when a tiny paint chip--the size of a grain of salt--struck the space shuttle Challenger. It gouged a deep pit in the orbiter's windshield.

Although the damage posed no immediate danger, the window was weakened beyond the allowable safety limit for flight and had to be replaced.

"Some things are just too small for us to see," acknowledges Air Force Col. Michael Ingelido, chief of space control operations for the Space Surveillance Network.

Debris poses a special hazard for long-term orbiting spacecraft such as the Hubble Space Telescope, which was launched in 1990. It stands a one-in-100 chance of being seriously damaged by space waste during its 17-year life expectancy, says Williamson, who directed the 1990 OTA congressional study.

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