Pentagon plans to shoot down disabled satellite

WASHINGTON - The Pentagon plans to shoot down a disabled U.S. spy satellite before it enters the atmosphere to prevent a potentially deadly leak of toxic gas from the vehicle's fuel tank, officials said on Thursday.

President George W. Bush opted for a plan to have the Navy shoot the 2,270 kg minivan-sized satellite with a modified tactical missile, after security advisers suggested its reentry could lead to a loss of life.

An aerial view of the Pentagon building is seen in Washington in this June 15, 2005 file photo. The Pentagon plans to shoot down a disabled U.S. spy satellite before it enters the atmosphere to prevent a potentially deadly leak of toxic gas from the vehicle's fuel tank, officials said on Thursday. (REUTERS/Jason Reed/Files)

Military officials hope to strike the satellite just before it reaches the atmosphere and drive it into ocean waters.

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 case a little bit different ... was the likelihood that the satellite upon descent to the Earth's surface could release much of its 454 kg of hydrazine fuel as a toxic gas," said James Jeffries, deputy national security adviser.

He told a Pentagon briefing the satellite was unlikely to hit a populated area and described the danger from toxic gas as limited. But Jeffries added: "There was enough of a risk for the president to be quite concerned about human life."

The satellite is a classified National Reconnaissance Office spacecraft launched from Vandenberg Air Force Base in California in 2006, according to four senior U.S. officials, who asked not to be named.

The satellite, known as L-21, has been out of touch since shortly after reaching its low-Earth orbit. Since the satellite never became operational, it has toxic rocket fuel on board that would have been used to maneuver the satellite in space.

Officials said about half the satellite, including the fuel tank, would survive reentry into Earth's atmosphere and estimated a crash could spread toxic material across an area equal to two football fields.

"The tank will survive. It will be breached. The hydrazine will reach the ground and that's not an outcome we want to see," NASA administrator Michael Griffin said at the briefing.

"It's hard to find areas that have any significant populations to them where you could put a toxic substance down across a couple of football fields and not have somebody at risk."