A missile fired from a US Navy warship has hit a defunct spy satellite in space in an effort to prevent its toxic fuel tank from crashing to Earth, a Pentagon source said.

"The missile's been launched and [it was] a successful intercept," the source said on Wednesday.

The SM-3 missile was fired from the USS Lake Erie in the Pacific Ocean at about 10:26 EST (0326 GMT Thursday), the Pentagon said in a statement.

There was no immediate word on whether the fuel tank, carrying 450 kgs of toxic fuel hydrazine, had been shattered as officials had hoped.

But the Pentagon statement said that confirmation the fuel tank had been fragmented should be available within 24 hours.

"Nearly all of the debris will burn up on re-entry [of the Earth's atmosphere] within 24-48 hours and the remaining debris should re-enter within 40 days," it said.

 Initial delay

The project was initially delayed after weather forecasts on Wednesday in the Pacific, where the US warship was stationed for the mission, indicated that seas would not be calm enough for the ship to fire a missile.

But the Pentagon had to act before February 29, when the dead satellite, about 247 km above the Pacific Ocean, was projected to re-enter the Earth's atmosphere.

On Wednesday, the space shuttle Atlantis landed in Florida, clearing the way for the military operation to proceed.

The Pentagon had been waiting for the shuttle to land to avoid contact with flying debris as the satellite returned to Earth.

Atlantis returned after completing a mission to deliver Europe's first permanent space laboratory to the International Space Station.

Health 'concerns'

Left alone, about half of the 5,000-pound spacecraft was expected to survive its blazing descent through the atmosphere and would scatter debris over several hundred miles.

The Pentagon said that George Bush, the US president, had decided the Navy should try to shoot down the satellite because if it entered the Earth's atmosphere, the hydrazine could have posed a health hazard to humans if it landed in a populated area.

PHOTO CAPTION 

The SM-3 missile fired from the USS Lake Erie in the Pacific Ocean.

Al-Jazeera