Honolulu, Feb. 21 (AP): A US navy cruiser blasted a disabled spy satellite with a pinpoint missile strike that achieved the main mission of exploding a tank of toxic fuel 210 km above the Pacific Ocean, defence officials said.

Destroying the satellite’s onboard tank of about 465 kg of hydrazine fuel was the primary goal. A senior defence official close to the mission said today that it appears the tank was destroyed, and the strike with a specially designed missile was a complete success.

According to the vice- chairman of the Joint Chiefs of Staff and an expert on military space technologies, General James Cartwright, debris from the satellite is being tracked over the Pacific and Atlantic oceans but appears to be too small to cause damage on Earth.

He told a Pentagon news conference that officials have a “high degree of confidence” that the missile launched from a navy cruiser last night hit exactly where intended. It was an unprecedented mission for the navy, so extraordinary that the final go-ahead to launch the missile yesterday was reserved for defence secretary Robert Gates rather than a military commander.

Cartwright estimated there was an 80 to 90 per cent chance that the missile struck the most important target on the satellite — its fuel tank, containing 465 kg of hydrazine, which Pentagon officials say could have posed a health hazard to humans.

Referring to a video clip of the missile smashing into the satellite, which he showed at the news conference, Cartwright said: “We have a fireball, and given that there’s no fuel (on the tip of the missile), that would indicate that that’s a hydrazine fire.”

The video showed the three-stage SM-3 launching from the USS Lake Erie, northwest of Hawaii, and of the missile’s small “kill vehicle” — a non-explosive device at the tip — manoeuvring into the path of the satellite and colliding spectacularly.

He said the satellite and the kill vehicle collided at a combined speed of 35,400 km per hour about 210 km above the Earth’s surface.

Cartwright cautioned, however, that more technical analysis was required to determine for certain what debris was created and where it might go. The satellite was described as the size of a bus and weighed about 2,268 kg.

The elaborate intercept may trigger worries from some international leaders, who could see it as a thinly disguised attempt to test an anti-satellite weapon — one that could take out other nations’ orbiting communications and spy spacecraft.

Within hours of the reported success, China said it was on the alert for possible fallout from the shootdown and urged the US to promptly release data on the action. “China is continuously following closely the possible harm caused by the US action to outer space security and relevant countries,” foreign ministry spokesman Liu Jianchao said.