U.S. has high confidence it hit satellite fuel tank

By Andrew Gray

WASHINGTON (Reuters) - The Pentagon said on Thursday it was very confident that a spectacular and unprecedented missile strike from a U.S. Navy warship had destroyed the toxic fuel tank of a defunct U.S. spy satellite.

The 1,000 pound (450 kg) fuel tank could have released its load of hydrazine fuel as a toxic gas if it had fallen to Earth, causing health risks for anyone nearby, officials said.

The strike took place 153 miles above the Pacific Ocean on Wednesday as the satellite sped through space at more than 17,000 mph (27,000 kph), the Pentagon reported.

"This was uncharted territory. The technical degree of difficulty was significant here," said Marine Gen. James Cartwright, vice chairman of the Joint Chiefs of Staff.

"You can imagine, at the point of intercept, there were a few cheers that went up in operations centers and on that ship," Cartwright told reporters at the Pentagon.

Both Russia and China had expressed concern ahead of the mission.

Moscow said it could be used as cover to test a new space weapon. China, criticized by Washington after it shot down one of its own satellites last year, said the operation may influence security in space and harm other countries.

U.S. Defense Secretary Robert Gates said Washington could share some information to reassure China about the operation.

"Our whole approach to this was one of complete transparency, prior notifications and letting everybody know what was going on and the purpose of the activity," Gates told reporters during a visit to Hawaii.

Washington said the only reason for the mission was to prevent harm to humans from fuel on the bus-sized satellite, which was expected to re-enter the Earth's atmosphere within the next couple of weeks.

"We're very confident that we hit the satellite. We also have a high degree of confidence that we got the tank," Cartwright said, putting the chances that the tank had been breached at around 90 percent.

FIREBALL SUGGESTS SUCCESS

Cartwright said a fireball in video images of the strike, a vapor cloud that formed and indications of hydrazine in the air all suggested the tank had been shattered. But he said it could take another 24 to 48 hours to know for sure.

Debris from the satellite had already started to re-enter the atmosphere over the Atlantic and Pacific oceans but nothing larger than a football had been detected so far, he said.

The 5,000-pound (2,300 kg) satellite was struck by an SM-3 missile fired from the USS Lake Erie northwest of Hawaii at 10:26 p.m. EST, the Pentagon said.