US shoots down toxic satellite

A MISSILE fired from a US Navy warship has hit a dying spy satellite 247km above the Pacific Ocean but it is not yet known whether the strike has nullified the threat of a toxic fuel landing in a populated area, the Pentagon says.

Australia is one of the countries that has been placed on alert because of the risk.

The SM-3 missile was fired from the USS Lake Erie in the Pacific at about 10.26 EST (2.26pm AEDT) and scored a direct hit on the bus-sized satellite, the Pentagon said.

The US Department of Defence (DoD) officially confirmed that the operation was a “success”.

“A network of land, air, sea and spaced-based sensors confirms that the U.S. military intercepted a non-functioning National Reconnaissance Office satellite which was in its final orbits before entering the earth's atmosphere,” the DoD said.

But the DoD said it would be some time before it was known if the toxic fuel would reach earth.

“The objective was to rupture the fuel tank to dissipate the approximately 1,000 pounds (453 kg) of hydrazine, a hazardous fuel which could pose a danger to people on earth, before it entered into earth's atmosphere.

“Confirmation that the fuel tank has been fragmented should be available within 24 hours.”

The DoD also said debris had already begun to enter the earth’s atmosphere, although most of it would burn up within 48 hours.

A defence official told the Associated Press that an initial view of the missile strike indicated it probably hit the fuel tank.

The Pentagon said last week that US President George W. Bush had decided the navy should try to shoot down the satellite because its tank of hazardous hydrazine could leak if it enters the atmosphere and reaches Earth.

Russia and China have expressed concern about the operation. The Russian Defence Ministry said it could be used as cover to test a new space weapon.

Washington has insisted the operation is purely to prevent people being harmed by the satellite's fuel load.