WASHINGTON — A Navy cruiser in the Pacific Ocean will try an unprecedented shoot-down of an out-of-control, school-bus-size spy satellite loaded with a toxic fuel as it begins its plunge to Earth, national-security officials said Thursday.
President Bush made the decision because it was impossible to predict where a tank containing the fuel might land in an uncontrolled descent.
The Pentagon decided to use a modified, ship-fired anti-ballistic missile to make the attempt after Feb. 20 to avoid creating debris that could threaten the space shuttle on its return from the international space station, a military source said.
Gen. James Cartwright, vice chairman of the Joint Chiefs of Staff, said the Navy missile, which will be fired as the 5,000-pound satellite re-enters the atmosphere, "has a reasonably high opportunity for success." The window of opportunity for taking the satellite down, Cartwright said, opens in three or four days and lasts for about seven or eight days.
The Pentagon and NASA have been working on the missile modifications for the past three weeks.
Deputy National Security Adviser James Jeffrey said the decision was based on the fact that the satellite is carrying a substantial amount of a hazardous rocket fuel, hydrazine.
Normally, aging satellites — their onboard fuel mostly consumed — are steered into the ocean at the end of their life. But with the spy satellite's power and communications inoperable, it is tumbling, unguided, to Earth.
Risk was downplayed
When the pending crash was announced last month, National Security Council spokesman Gordon Johndroe minimized the danger, saying the potential for pieces hitting any populated area was "very small."
Unless it is shot down, the satellite, which has been out of ground communication since its launch more than a year ago, is expected "to make an uncontrolled re-entry ... on or about March 6," according to documents the Bush administration provided to the United Nations on Thursday. "At present," said an official notification sent Thursday to countries around the world as well as the U.N. and NATO, "we cannot predict the entry impact area."
Cartwright declined to say who built the satellite, known by its military designation US 193, or its purpose. Various aviation publications said Lockheed Martin built it at a cost of several hundred million dollars for the National Reconnaissance Office, the government agency that manages many of the nation's spy satellites. Lockheed Martin spokesman Chip Manor declined to provide additional details.
Officials Thursday acknowledged that many satellites — some much larger — have fallen to Earth in the past without harm. But they said the presence of 1,000 pounds of hydrazine — unexpended fuel contained in a 40-inch sphere that was likely to hit the ground intact — led Bush to approve the Pentagon's recommendation to attempt the shoot-down. If the missile shot is successful, officials said, much of the debris will burn up as it falls. The goal is to hit the fuel tank in order to minimize the amount of fuel that returns to Earth, Cartwright said.
The announcement set off an immediate debate on defense blogs and among experts who questioned whether there was an ulterior motive. Some experts said the military was seizing an opportunity to test its controversial missile-defense system against a satellite target.
But others noted that the Standard Missile-3 has successfully been tested against warhead targets, which are far smaller than the satellite.
"There has to be another reason behind this," said Michael Krepon, co-founder of the Henry L. Stimson Center, a liberal arms-control advocacy organization. "In the history of the Space Age, there has not been a single human being who has been harmed by man-made objects falling from space."
NASA administrator Michael Griffin insisted the interception was not a ruse to try the defense system on a satellite or to one-up other countries that have made similar attempts. The administration was harshly critical of China when it destroyed an aging satellite in orbit.
The difference, Griffin said, "is, one, we are notifying, which is required by treaties and law. OK?" The Chinese satellite was destroyed at a much higher altitude — about 600 miles — forming a field of orbiting space debris that creates hazards for other spacecraft.
The United States and the Soviet Union conducted anti-satellite tests in the mid-1980s but stopped once it became clear the debris from the destroyed spacecraft became a danger to other satellites and spaceships. Griffin said the low altitude at which the satellite will be targeted — about 150 miles — would minimize orbiting debris.
"The lower we can catch this, the quicker the debris re-enters," he said. More than half the pieces will burn up or hit Earth before making two revolutions around the Earth, and the rest will come down in "weeks, maybe a month, but it's a very finite period of time that we can manage."
Jeffrey said the fuel tank was the only piece of the craft that was not expected to explode on re-entry, and it was hoped the missile could destroy it in space. If it hits the Earth, it could leak gas and cause potentially fatal injury over an area the size of about two football fields, he said, adding that "this is all about trying to reduce the danger to human beings."
Other experts, however, said they believed the heat of re-entry would cause the tank to explode safely high in the air.
Two additional U.S. Navy cruisers, with backup missiles, have been configured for a second and third chance, if necessary, Jeffrey said. Cartwright said that if an initial shoot-down attempt fails, the military will have about two days to decide whether to take a second shot.
The satellite was never ordered to burn its maneuvering hydrazine fuel, a substance Cartwright compared to "chlorine or to ammonia in that when you inhale it, it affects your tissues in your lungs ... If you stay very close to it and inhale a lot of it, it could in fact be deadly."
Details on missile
Cartwright said the Aegis missile system aboard the Navy cruiser will fire a Standard Missile-3 with a heat-seeking nose that destroys its target by hitting it, not blowing it up.
The Navy spent the past three weeks modifying missile software normally set for hitting much higher targets, he said.
The Pentagon would not say which ship would be assigned the task. One Aegis cruiser, the Lake Erie, has conducted more extensive testing than other ships of the Standard Missile-3. The Lake Erie is stationed at Pearl Harbor, Hawaii.
Asked whether this was an attempt to test the Aegis system for use as an anti-satellite system, Cartwright said the amount of special modifications being done to the programs used to guide the system would "not be transferable to fleet use."
He also rejected blog allegations that the destruction of the satellite had been planned to keep classified information aboard from landing in non-U.S. hands. Everything other than the gas container, he said, would be blown to pieces on re-entry even without the missile hit, he said.
Members of Congress were briefed on the plan Thursday, as were diplomats from other nations.
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