HONOLULU, Hawaii (AFP) - A US missile shot down a rogue US spy satellite in space carrying dangerous toxic fuel, demonstrating the effectiveness of America's missile defense system, officials said Thursday.
However, the operation raised Chinese concerns that the United States was trying to test an anti-satellite weapon, amid rising global tensions about the militarization of space.
"I think the question over whether this capability works has been settled," Defense Secretary Robert Gates told reporters after touring one of the warships that supported the operation Wednesday evening in the Pacific ocean.
"The question is what kind of threat, how large a threat, how sophisticated a threat (the United States faces)."
A network of radars and satellites designed for the US missile defense system confirmed that the successful interception occurred some 250 kilometers (150 miles) over the Pacific Ocean, US officials said Wednesday.
The missile that struck the satellite reduced it to football-sized chunks, and the Pentagon said it had a "high degree of confidence" its fuel tank was destroyed.
General James Cartwright told reporters at the Pentagon it would be 24-48 hours before a full confirmation would be available on the fuel tank.
A senior Pentagon official earlier had said the missile appeared to have struck the fuel tank containing hydrazine, which could have leaked toxic gas over a wide area if it had survived re-entry into the Earth's atmosphere.
"The intent here was to preserve human life ... it was the hydrazine we were after," said Cartwright, who is vice chairman of the Joint Chiefs of Staff, rejecting Moscow's suggestion it was an anti-missile test.
"This is a modified system, this isn't a missile defense system," he said, adding that so far the United States has not seen debris touch the Earth's surface.
China called on Washington to provide more information and warned of potential international consequences.
"China is continuing to closely follow the possible harm caused by the US action to outer space security and relevant countries," foreign ministry spokesman Liu Jianchao said.
China caused an international outcry when it shot down one of its own weather satellites on January 11, 2007 in what was widely seen as an anti-satellite test.
Asked about China's request that Washington provide information about the satellite strike, Gates said: "We're prepared to share whatever, appropriately, we can."
Gates approved the missile strike as he flew from Washington to Honolulu, a base for the three Aegis warships involved in the intercept attempt.
The USS Lake Erie, a guided missile cruiser, fired a single modified tactical SM-3 missile that hit the schoolbus-sized satellite as it traveled at more than 7,000 miles (11,265 kilometers) per hour, the Pentagon said.
The objective was to hit a tank containing 1,000 pounds of hydrazine fuel.
Satellite debris will re-enter the Earth's atmosphere immediately because of the relatively low altitude at which the satellite was intercepted, and most will burn up on re-entry within two days, the Pentagon said. But it could take up to 40 days for all the debris to re-enter.
Russia's defense ministry said on Sunday that the US plans looked like a veiled weapons test and an "attempt to move the arms race into space."
US officials have insisted that the aim was to prevent potential risk to humans from the de-orbiting satellite, and not to test an anti-satellite weapon or keep its secrets from falling into the wrong hands.
In France, some experts did not buy the hydrazine explanation. Strategic Research Foundation researcher Xavier Pasco said 450 kilograms of the substance posed a "tiny risk, since it would burn off in the atmosphere without it needing to be destroyed."
For a French Defense Ministry analyst who remained anonymous, the satellite shootdown was merely a great opportunity for Washington to "showcase its power (and) put the clock back" to the time when US military power was unquestioned.
Admiral Timothy Keating, the head of the US Pacific command, acknowledged similarities with the Chinese shoot down but said this one was significantly different because the United States gave public notice first.