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US plans to shoot down broken satellite
2008-02-14
President Bush decided to make a first-of-its-kind attempt to use a missile to bring down a broken U.S. spy satellite because of the potential danger to people from its rocket fuel, officials said Thursday. Deputy National Security Adviser James Jeffries, briefing reporters at the Pentagon, did not say when the attempted intercept would be conducted, but the satellite is expected to hit Earth during the first week of March. Gen. James Cartwright, vice chairman of the Joint Chiefs of Staff, said at the same briefing that the "window of opportunity" for such a shootdown, presumably to be launched from a Navy ship, will open in the next three or four days and last for seven or eight days. He did not say whether the Pentagon has decided on an exact launch date. Cartwright said this will be an unprecedented effort; he would not say exactly what are the odds of success. "This is the first time we've used a tactical missile to engage a spacecraft," Cartwright said. After extensive study and analysis, U.S. officials came to the conclusion that, "we're better off taking the attempt than not," Cartwright said. He said a Navy missile known as Standard Missile 3 would be fired in an attempt to intercept the satellite just prior to it re-entering Earth's atmosphere. It would be "next to impossible" to hit the satellite after that because of atmospheric disturbances, Cartwright said. A second goal, he said, is to directly hit the fuel tank in order to minimize the amount of fuel that returns to Earth. Cartwright also said that if an initial shootdown attempt fails, a decision will be made whether to take a second shot. Shooting down a satellite is particularly sensitive because of the controversy surrounding China's anti-satellite test last year, when Beijing shot down one of its defunct weather satellites, drawing immediate criticism from the U.S. and other countries. A key concern at that time was the debris created by Chinese satellite's destruction -- and that will also be a focus now, as the U.S. determines exactly when and under what circumstances to shoot down its errant satellite. The military will have to choose a time and a location that will avoid to the greatest degree any damage to other satellites in the sky. Also, there is the possibility that large pieces could remain, and either stay in orbit where they can collide with other satellites or possibly fall to Earth. It is not known where the satellite will hit. But officials familiar with the situation say about half of the 5,000-pound spacecraft is expected to survive its blazing descent through the atmosphere and will scatter debris -- some of it potentially hazardous -- over several hundred miles. The officials spoke on condition of anonymity because of the sensitivity of the matter. The satellite is outfitted with thrusters -- small engines used to position it in space. They contain the toxic rocket fuel hydrazine, which can cause harm to anyone who contacts it. Officials have said there is about 1,000 pounds of propellent on the satellite. Known by its military designation US 193, the satellite was launched in December 2006. It lost power and its central computer failed almost immediately afterward, leaving it uncontrollable. It carried a sophisticated and secret imaging sensor.
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