U.S. to shoot down broken satellite

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http://www.nytimes.com/2008/02/14/science/14cnd-satellite.html?_r=1&hp&oref=slogin

U.S. Officials Say Broken Satellite Will Be Shot Down
By DAVID STOUT and THOM SHANKER
Published: February 14, 2008

WASHINGTON — The Pentagon plans to shoot down a disabled 5,000-pound spy satellite because the rocket fuel it carries could be a danger to people, Pentagon officials said Thursday.

The operation will be carried out from a Navy ship that will fire a Standard Missile 3 anti-aircraft device, Gen. James C. Cartwright, the vice chairman of the Joint Chiefs of Staff, said at a Pentagon briefing. Navy ships routinely carry missiles to shoot down aircraft, and the Pentagon will modify the missile or missiles to be fired at the satellite, Pentagon officials said.

President Bush ordered the military to try to pick off the satellite because “there was a possibility of death or injury to human beings beyond that associated with the fall of satellites and other space objects normally, if we can use that word,” a deputy national security adviser, James Jeffries, said.

General Cartwright, of the Marine Corps, said that “a window of opportunity” would open in the next three to four days to pick off the satellite before it enters Earth’s atmosphere, and that the Navy then would have seven to eight days to take up to two shots at the satellite, if necessary. If the satellite is not destroyed, it will tumble out of control into the atmosphere in early March, he said.

Many satellites have fallen harmlessly out of orbit during the space age, in part because they often break apart and the pieces generally burn upon re-entry. And when pieces do survive re-entry, they have usually landed in remote areas or in an ocean, simply because the Earth’s surface has more remote regions and seas than it does heavily populated areas.

What makes this case different is the presence of up to 1,000 pounds of hydrazine, the highly toxic fuel used in thrusters to control a satellite’s movements, and the likelihood that the fuel tanks could survive re-entry, the officials said.

The operation involves the Department of Homeland Security, the State Department, the National Aeronautics and Space Administration and other agencies in addition to the Defense Department.

The ramifications of the operation are diplomatic as well as military and scientific, in part because the United States criticized China last year when Beijing used a defunct weather satellite as a target in a test of an antisatellite system.

After their test, the Chinese said that they had no intention of getting involved in a “space race,” and that their test had not been designed to intimidate. Under the Bush administration, the United States has asserted its need to protect its interests in space. The United States is heavily dependent on satellites for military communications, reconnaissance and targeting, as well as civilian purposes.

Some arms control experts criticized the Bush administration’s decision to shoot down the satellite. “It is not a good idea,” said Jeffrey G. Lewis, an arms control specialist at the New America Foundation. One concern, he said, is the risk that the intercept may produce orbital debris. To minimize the chances of spewing debris, he said, American missile defense tests are carefully designed so that the targets are intercepted when they are on their downward trajectory, which would not be the case with the satellite intercept.

Beyond that, he said, China would cite the intercept to justify the antisatellite test it conduct last year. “The politics are terrible,” Mr. Lewis said. “It will be used by the Chinese to excuse their hit-to-kill test. And it really strengthens the perceived link between antisatellite systems and missile defenses. We will be using a missile defense system to shoot down a satellite.”

The United States shot down a satellite in September 1985, as a test of an antisatellite system under development. In that experiment, an F-15 Eagle fighter aircraft fired a missile armed with a “kill” vehicle that collided with the U.S. Solwind satellite.

Gordon Johndroe, a spokesman for the National Security Council, said in late January that the problem satellite was moving in a circular orbit about 170 miles above the Earth. In the previous month, its orbit had declined as much as 12 miles.

Specialists who follow spy satellite operations had speculated, correctly, that the problem satellite is an experimental imagery device built by Lockheed Martin and launched from Vandenberg Air Force Base in California aboard a Delta II rocket. Shortly after it reached orbit, ground controllers lost the ability to control it and were unable to regain communication.

“Not necessarily dead, but deaf,” as Jonathan McDowell, an astronomer at the Harvard-Smithsonian center for Astrophysics, put it in late January.

John E. Pike, the director of Globalsecurity.org in Alexandria, Va., said in January that assuming the satellite in question was indeed a spy satellite, it would probably not contain any nuclear fuel, but that it could contain toxins, including beryllium, often used as a rigid frame for optical components. Moreover, it is possible that any surviving debris could be scattered over several hundred square miles.

If the satellite is destroyed before plummeting to earth, there would be less chance of sensitive American technology being compromised, Mr. Pike said. “We are worried about something showing up on e-Bay,” he told The A.P.

As for the possibility that debris could strike a population center, Mr. McDowell said in January that “one could say we’ve been lucky so far.”

The largest uncontrolled re-entry by an American spacecraft was that of Skylab in 1979. Controllers changed the 78-ton abandoned space station’s orientation to vary atmospheric drag to shift its entry point. Much of the craft fell into the Indian Ocean, as predicted, but some pieces traveled farther than expected, falling harmlessly in Western Australia.

Michael R. Gordon contributed reporting.
 
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