U.S. Navy Successfully Shoots Down Inoperable Spy Satellite

An inoperable U.S. spy satellite orbiting about 150 miles above Earth was struck Wednesday by a missile fired from a U.S. Navy cruiser, military sources told CNN.

The Pentagon said the window of opportunity to strike the 5,000-pound satellite opened Wednesday, when the space shuttle Atlantis landed in Florida. The Pentagon wanted to be sure the shuttle would not be struck by any debris from a destroyed satellite.

But earlier the official said conditions had to be perfect, and that was not the case Wednesday with swells in the Pacific Ocean west of Hawaii running slightly higher than Navy would like.

CNN meteorologist Chad Myers said six- to eight-foot swells were reported in the area through Wednesday night and were not expected to come down until Friday or Saturday.

The United States planned to spend up to $60 million trying to destroy the satellite even though there was only a remote possibility the satellite could fall to Earth, survive re-entry and spew toxic gas in a populated area, said James Jeffrey, deputy national security adviser.

"The regret factor of not acting clearly outweighed the regret factor of acting," he said.

The Chinese military destroyed an aging weather satellite last year, prompting questions about whether the United States is merely flexing its muscle to show an economic and military rival that it can destroy satellites, too. Jeffrey denied that when a reporter asked him about it this week.

"This is all about trying to reduce the danger to human beings," he said.

In 1989, a U.S. fighter jet destroyed a U.S. satellite by firing a modified air-to-air missile into space from an altitude of 80,000 feet. That adds to evidence that the U.S. is acting Wednesday strictly to guard against the prospect of a potential disaster, said Gen. James Cartwright, vice chairman of the U.S. Joint Chiefs of Staff.

Without intervention, officials say, the satellite would have fallen to Earth on its own in early March. However, since it malfunctioned immediately after it was launched in December 2006, it has a full tank -- about 1,000 pounds -- of frozen, toxic hydrazine propellant.

Authorities said the fuel tank probably would have survived re-entry and could have dispersed harmful or even potentially deadly fumes over an area the size of two football fields. Hydrazine is similar to chlorine or ammonia in that it affects the lungs and breathing tissue.

The goal was to strike the satellite in low orbit, just before it re-entered the Earth's atmosphere, at an altitude of about 150 miles. The missile didn't carry a warhead. The idea was to blast the satellite apart on impact so that the hydrazine tank explodes.

The smaller debris would be more likely to burn up in the atmosphere. Most of the debris would re-enter the atmosphere within hours of impact, NASA Administrator Michael Griffin has said.

The military timed its shoot-down attempt so that resulting debris would tumble into the atmosphere and not interfere with other satellites, said Christina Rocca, a U.S. diplomat and expert on disarmament. Her comments were included in an online United Nations report on this month's Conference on Disarmament in Geneva, Switzerland.

The military also timed its efforts to minimize the chances that debris would hit populated areas. But the United States is "prepared to offer assistance to governments to mitigate the consequences of any satellite debris impacts on their territory," according to a report of Rocca's remarks on the Web site of the Geneva office of the U.N.

If the satellite is not destroyed, she said, it's expected to make an "uncontrolled re-entry into the Earth's atmosphere" on or about March 6.

President Bush made the decision to shoot the satellite down after consulting with several government and military officials and aerospace experts, Jeffrey said earlier in February.

One Pentagon official said that since early January, a Navy team including 200 industry experts and scientists had worked furiously to modify the Aegis air-defense missile system so it could shoot down the satellite. Among the team's challenges was modifying the sensors designed to detect the heat from an incoming warhead, as the satellite will be much cooler. (CNN)