Weather conditions may force the US Navy to halt plans to launch a heat-seeking missile on a mission to shoot down a rogue US spy satellite, said the Pentagon on Wednesday. High seas in the north Pacific, and other factors are being considered as the Navy decides whether to proceeds with the mission or put it off for another day.

But according to an official at the Pentagon, it is assumed that the mission would go forth Wednesday evening, unless weather conditions are determined to be unfavorable. Early on Wednesday they were facing bad weather and rough seas, which could be a problem for the USS Lake Erie, a cruiser armed with two SM-3 missiles. Defense Secretary Robert Gates will get the final call on whether to go forth.

The Pentagon had also been waiting for the return of the space shuttle Atlantis to the Earth, before launching the missile. Atlantis landed at 9:07am EST, so that is no longer a factor holding up the mission.

The satellite is expected to have re-entered the Earth's atmosphere by February 29, which gives them a short window of opportunity to shoot it down. Once the satellite enters the atmosphere, it would be infeasible to attempt to hit it with the Navy missile.

President Bush approved the attempted shootdown of the satellite last week, after concerns that toxic fuel on board the satellite could crash to earth and potentially harm humans.

Once the SM-3 missile has been launched, the Navy will know within minutes whether they've hit their target. However, it will take at least a day or two to determine whether or not the fuel tank has been destroyed.

The US government issued noticed to mariners and aviators to stay clear of a section of the Pacific Ocean beginning at 10:30pm EST Wednesday.

The rogue satellite lost power shortly after reaching orbit in late 2006. The satellite is now out of control, and below the altitude of a normal satellite. The mission to hit the satellite with a missile is an attempt to minimize the amount of debris that would remain in space.

If the 5,000-pound satellite were left to its own devices, it is expected to hit earth in the first week of March. About half of the spacecraft would be expected to survive entering the atmosphere, and the debris would be scattered over several hundred miles.

Internationally, both China and Russia have expressed concerns over the mission, stating that it could harm security in outer space.