The Pentagon plans to shoot down a disabled US spy satellite before it enters the atmosphere to prevent a potentially deadly leak of toxic gas from the vehicle's fuel tank.
President George W. Bush decided to have the Navy shoot the 2,270 kg minivan-sized satellite with a modified tactical missile, after security advisers suggested its re-entry could lead to a loss of life.
US officials said they were not trying to protect classified information on the satellite or to demonstrate their capabilities to China, which downed one of its own satellites with a missile last year, drawing criticism from Washington.
Some experts disagreed and questioned the risks associated with shooting down the satellite.
Two defence officials also cited disagreement within the administration over the action and said the decision appeared to have been strongly influenced by the White House.
The Pentagon hopes to strike the satellite just before it reaches the atmosphere and drive it into ocean waters. Officials would not estimate the likelihood of success, only calling it high.
Thousands of space objects fall to Earth each year, but they generally scatter over a huge area and there have never been any reported injuries.
What makes this different is the likelihood the satellite could release much of the up to 500kg of hydrazine fuel as a toxic gas.
