As the Pentagon continued to scan debris from an errant spy satellite struck by a Navy missile, officials said yesterday that results so far look good.

Preliminary reports showed that the SM-3 missile launched by the USS Lake Erie likely destroyed the satellite's hydrazine fuel tank 153 miles above Earth, leaving no pieces larger than a football.

"If that's true, there should be no danger to anyone," said Ray Sedwick, an assistant professor of aerospace engineering at the University of Maryland.

Relief and pride

The Navy's success also inspired feelings of relief and pride in employees at Maryland defense contractors who made key equipment used in the mission.

"We're pretty proud of it, pretty proud that it worked," said Tracy Imm, a spokeswoman for ATK-Mission Systems Group, which operates the Elkton plant where two components for the SM-3 missile used in the strike were manufactured under subcontract to Raytheon.

The missile intercepted the satellite just before it entered Earth's atmosphere Wednesday night, according to Department of Defense officials. But they said it would take up to 48 hours before the Pentagon could announce with full confidence that the mission was a success.

Video shows the missile hitting the 5,000-pound satellite, known as USA 193, and turning it into a fireball, with a vapor cloud that suggested to military officials that the fuel tank had been hit and the hydrazine burned up.

That's good news, according to UM's Sedwick. Debris from satellites and meteors falls to Earth all the time, but the smaller the object, the less likely it will reach Earth's surface.

The 5,000-pound satellite was traveling about 18,000 mph when the missile struck it, and at that speed, the air beating against it would heat up its surface, he said. So if the satellite was in fact broken into pieces the size of a football or smaller, they will almost certainly burn up.

"The smaller the object, the less travel distance you need for it to burn up," Sedwick said.

Any of the frozen hydrazine vented from the tank also is likely to burn up because at 18,000 mph, friction will heat it to temperatures of at least 400 degrees Fahrenheit, he said.

"If the tank had remained intact, it could have survived re-entry into the atmosphere and been a problem," Sedwick said.

At Lockheed Martin, officials boasted yesterday about the MK41 launcher, made at the company's Middle River plant, that the Navy used in the mission.

High-profile mission

"It was a high-profile mission, so obviously you want to have success," said Paul Lemmo, director of business development for the company's Maritime Security and Ship Systems division. The company has been selling the Navy its launchers since 1984 and, in recent years, has sold them to 11 foreign governments.

Raytheon, the missile's manufacturer, also weighed in with a statement: "Much engineering and technical expertise made this one-time mission possible, with Raytheon engineers working closely with our customers throughout the operation."

Lockheed Martin officials were less willing to discuss the company's errant satellite, which malfunctioned shortly after launch in December 2006. The satellite, orbiting Earth every 90 minutes, was expected to fall from the sky in late February or March - with its tank of hydrazine. Pentagon officials said it had to be destroyed because of the safety risk posed by the hydrazine.

A Lockheed Martin spokesman referred questions about the satellite to the Pentagon, which declined to discuss it. Federal laws prohibit contractors from discussing details of many military contracts.

dennis.obrien@baltsun.com