Shot at satellite might come Wednesday night

"We all have an agreed-upon series of steps that need to be taken for this launch to be given the go-ahead," Morrell said, adding that no final decision has been made on when to make the attempt.

"The secretary is the one who will decide if and when to pull the trigger," the spokesman said, adding that Gates was departing Wednesday morning on an around-the-world trip that will include a stop in Honolulu, Hawaii, where a military command center will be monitoring the satellite operation.

Left alone, the satellite would be expected to hit Earth during the first week of March. About half of the 5,000-pound spacecraft would be expected to survive its blazing descent through the atmosphere and would scatter debris over several hundred miles.

Known by its military designation US 193, the satellite was launched in December 2006. It lost power and its central computer failed almost immediately afterward, leaving it uncontrollable. It carried a sophisticated and secret imaging sensor.

Morrell said the cost of adapting the Navy anti-missile system for the shootdown mission was $30 million to $40 million.

China and Russia have expressed concern at the planned shootdown, saying it could harm security in outer space. At the State Department on Tuesday, spokesman Sean McCormack told reporters that the U.S. action is meant to protect people from the hazardous fuel and is not a weapons test.

China was criticized last year when it used a missile to destroy a defunct weather satellite.

The Navy ship-based system, which includes a command-and-control and radar system known as Aegis, as well as the SM-3 missiles, is just one segment of a larger, far-flung missile defense system that has been in development by the American military for more than three decades.

Managed by the Pentagon's Missile Defense Agency, the program includes interceptor missiles sitting in underground silos at Fort Greely, Alaska, and at Vanderberg Air Force Base, Calif., as well as radars around the world that are used to track an enemy missile and help the interceptor hit it.

As currently configured the missile defense system is designed mainly to counter a threat from North Korea. The Bush administration, fearing an emerging missile threat from Iran, is in talks with Poland and the Czech Republic to place interceptor missiles in Poland and a tracking radar in the Czech Republic. Russia has objected strenuously, saying such bases would be a threat to Russia.

MORE FROM SPACE

Space Section Front

Cosmic Log: Cassini's closest encounter Space toilet goes on the fritz ... again! NASA to push ahead with Mars Lab launch Space millionaire confident ahead of liftoff Where have all the little Plutos gone? Cosmic Log: The plan to revive Hubble Interactive gallery: 8 great space telescopes High-speed crash makes hot, 'sterile' galaxies Planetarium entangled in politics   See fireworks on the final frontier Space Section Front   Add Space headlines to your news reader: