Pentagon officials said a missile will be fired from a U.S. Navy cruiser to shoot down a broken spy satellite before it enters Earth's atmosphere.

Deputy National Security Adviser James Jeffries, briefing reporters at the Pentagon, did not say when the attempted intercept would be conducted, but the satellite is expected to hit Earth during the first week of March.

Gen. James Cartwright, the vice chairman of the military Joint Chiefs of Staff, said at the same briefing that in a worst-case scenario, the rocket fuel could be deadly if inhaled.

Cartwright said that the amount of fuel would cover roughly the size of two football fields. He said he was not certain whether the hydrazine would be in gas or liquid form on re-entry, but that it is frozen now because the satellite has no power going to it.

Cartwright said the satellite was put into orbit Dec. 14, 2006, and went dead for communications or control shortly after it was in orbit.

"With no communications with the satellite, there's no way to communicate with it to invoke safety measures," Cartwright said.

Cartwright said the "window of opportunity" for such a shootdown will open in the next three or four days and last for seven or eight days. He did not say whether the Pentagon has decided on an exact launch date.

He said a Navy missile known as Standard Missile 3 would be fired in an attempt to intercept the satellite just prior to its re-entry into Earth's atmosphere. It would be "next to impossible" to hit the satellite after that because of atmospheric disturbances, Cartwright said.

The attempt won't happen until after the space shuttle Atlantis lands from its current mission.

Shooting down a satellite is particularly sensitive because of the controversy surrounding China's anti-satellite test last year, when Beijing shot down one of its defunct weather satellites, drawing immediate criticism from the U.S. and other countries.