WASHINGTON — The Bush administration has decided to try to shoot down a failing 5,000-pound spy satellite, fearing its rocket fuel could turn into a deadly toxic gas if the spacecraft crashed in a populated area, officials said Thursday.
The unusual operation, to be carried out in the next several days, would be the first U.S. attempt to shoot down a satellite since Cold War-era military tests ended in the 1980s.
Pentagon officials plan to use the same ships and missiles that are part of the Navy's nascent missile defense system. Ships in the North Pacific plan to fire a tactical missile at the satellite when it reaches a low orbit of about 150 miles over their general location.
Some experts theorized that the administration was influenced by concern that classified components on the intelligence satellite could fall into hostile hands. Denying that, Marine Gen. James E. Cartwright, vice chairman of the Joint Chiefs of Staff, said any sensitive instruments would burn on reentry.
"Once you go through the atmosphere and the heating and the burning, that would not be an issue in this case," Cartwright said at a news conference. "It would not justify using a missile to take it and break it up further."
However, the government has never resorted to shooting down a disabled spacecraft or satellite, despite dozens of crashes and reentries over decades of spaceflight. Administration officials said this instance is different because the satellite failed shortly after its launch in December 2006, leaving almost all of its 1,000 pounds of hydrazine rocket fuel frozen in the uncontrollable spacecraft.
Because of its size -- Cartwright compared it to a bus -- only half of the craft is likely to burn on reentry. That means the fuel tank could survive if it is not destroyed by the missile strike. Normally, aging satellites -- their onboard fuel mostly consumed -- are steered into the ocean at the end of their life. But with the spy satellite's power and communications inoperable, it is tumbling, unguided, to Earth.
Officials compared the effects of hydrazine fuel to those of chlorine or ammonia.
"It affects your tissues and your lungs -- it has the burning sensation," Cartwright said. "If you stay very close to it and inhale a lot of it, it could in fact be deadly."
Experts on military satellites agreed that the dispersal of hydrazine could pose a serious health hazard, although even Cartwright said it likely would be spread only over an area the size of two football fields.
