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Chinese missile test draws attention to dangers of space debris

BEIJING—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.

They said it may only be a matter of time before a weather, communications or other satellite—or the manned International Space Station—slams into space rubbish.

The debris travels through space at about 17,400 mph, 10 times faster than a bullet from a high-powered rifle and 100 times faster than a racecar. A millimeter-sized orbiting fleck of aluminum can have the kinetic energy of a bullet against a billion-dollar satellite, said Fernand Alby, the chief of debris monitoring at the French space agency, CNES.

"The breakup of Fengyun-1C is by far the most severe satellite breakup ever in terms of identified debris," said Nicholas I. Johnson, the chief scientist for orbital debris at the Lyndon B. Johnson Space Center in Houston.

The missile that China launched from the Xichang space center in Sichuan province obliterated a defunct Fengyun-1C weather satellite and showed the country's space might.

At first, scientists spotted 700 or so large pieces of debris from the test. But Johnson said the U.S. Space Surveillance Network later tracked more than 1,500 large shards from the shattered Chinese satellite, most of them measuring 4 inches (10 centimeters)—the size of a teacup—or larger. Smaller debris is far more numerous.

"NASA estimates that the number of debris 1 centimeter (4/10 of an inch) and larger are on the order of 35,000," Johnson said, adding that when tiny particles are included the number of flying objects and particles may reach 2 million.

As NASA's tally has climbed, so has anxiety among operators of commercial satellites and specialists at European and U.S. space programs.

France operates 14 civilian and military observation and communications satellites in low Earth orbit, and now deals with high-risk conjunctions—near-misses in space closer than 1 mile—with space fragments once every two weeks on average. "The collision risk has been increased by something like 30 percent," Alby said.

Senior U.S. military officers, caught by surprise by the Chinese test, have voiced strong irritation at what they say was the reckless creation of a 2,000-mile-long cloud of space debris.

"Platforms costing billions of dollars to replace and the lives of astronauts from many nations are now at risk from debris left by China's recent ill-advised anti-satellite test," Marine Corps Gen. James E. Cartwright, the head of the U.S. Strategic Command, which oversees space activities, told a House of Representatives panel earlier this month.

China has defended the test but hasn't addressed the issue of debris.

"It did not pose a threat to anyone, nor did it violate the relevant international treaties," Premier Wen Jiabao said at a news conference March 16.

A variety of Chinese space experts refused requests for interviews. Li Ming, the Chinese host of a meeting in late April in Beijing of the world's top space-junk experts, the Inter-Agency Space Debris Coordination Committee, also declined to speak.

"I think they don't like the situation," said Heiner Klinkrad, an orbital debris specialist at the European Space Operations Center in Darmstadt, Germany.

"The people I know in China are certainly guys who want to keep space clean," Klinkrad added. "But there are other trends in China of people who want to use space for their own purpose."

Since 2003, China has sent men into space twice. It will launch a lunar orbiter later this year, and plans to put an astronaut on the moon within 15 years, part of a program to build national prestige.

The last time the United States conducted an anti-satellite test, littering debris in the heavens, was in 1985. The former Soviet Union also conducted such tests.

At the time of the Chinese test, NASA radar was tracking roughly 10,000 large pieces of debris in space, so the debris from the 1,650-pound Fengyun-1C increased by about 15 percent the number of items that NASA must track for U.S. satellites or manned spacecraft to avoid collision.

Some of the debris from the Chinese satellite has already fallen to Earth, but Johnson of NASA said most would "remain in orbit for many decades, up to a century or more."

Compounding the debris problem, the upper stage of a Russian Proton rocket exploded over Australia on Feb. 19, littering the skies with as many as 1,000 pieces of rubble.

As the junkyard overhead grows, officials remain on alert to fire up the thrusters on satellites to avoid collisions.

"It's making life difficult for everyone who wants to use space as a platform," said Brian Embleton of Australia's Cooperative Research Centre for Satellite Systems.

Some 850 imaging, meteorological, communications and surveillance satellites soar in low Earth orbit. An Australian company, Electro Optic Systems, puts the value of satellites in low Earth orbit at $630 billion, a sign of the size of the global space industry.

The International Space Station also is endangered by the Chinese cloud. According to Alby, the French space-debris expert, NASA is monitoring the collision risk only of the larger debris.

The space station, with three astronauts aboard at an altitude of about 220 miles, is a joint project of NASA and the space agencies of Canada, Japan, Russia and Europe. It's been inhabited continuously since late 2000, and completes an orbit of Earth every 92 minutes.

Shields on the station protect it from pings by smaller debris. Large debris is another matter.


(c) 2007, McClatchy-Tribune Information Services.

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