Now that the space shuttle Atlantis has landed safely and is out of the way, the Navy will take aim this week at a crippled satellite that is hurtling toward Earth.
If a missile launched by the Navy succeeds in taking out the bus-sized satellite as streaks across the sky 150 miles up, it will be one of the longest shots ever.
ABCNEWS has learned the first window to launch a missile at the satellite begins at 9:30 p.m. ET Wednesday. The FAA sent an advisory warning to ships and planes to stay clear of a large area of the Pacific Ocean west of Hawaii. They may not actually pull the trigger, however, until Thursday night.
The Aegis cruiser USS Lake Erie is already at sea, hundreds of miles west of the Hawaiian Islands. As the primary ship in the mission, it is carrying two missiles, one of which will be used in the shoot down. The destroyer USS Decatur is en route to join the Lake Erie with another backup missile. The USS Russell will remain in its home port of Pearl Harbor, assisting with tracking.
Pentagon officials had always expressed a high degree of confidence that the satellite, known as USA-193, could be brought down on the first try. Gen. James Cartright suggested last week that there was an 80 to 90 percent chance of scoring a bull's eye.
The Pentagon won't provide advance warning of the shootdown attempt, but within an hour of an interception the Department of Defense will issue a statement announcing the launch, Pentagon Press Secretary Geoff Morrell said Tuesday.
According to Morrell, Defense Secretary Robert Gates will make the final launch decision. Gates leaves Wednesday night for a trip to India, Indonesia and Australia and is prepared to make the decision from the road.
"The president has made a decision about how he wants to deal with the threat -- the potential threat posed by this dying satellite and the hydrazine it carries in its tank. Now, with that decision made, the secretary is the one who will decide if and when to pull the trigger -- pardon the term -- on the missile launch," Morrell told reporters.
Shuttle, Space Station Safety is Paramount
First, however, NASA had to get Atlantis and its crew safely back on the ground. Officials never feared that the shuttle would be hit by a missile, but instead that the debris resulting from a direct hit could cause problems.
Atlantis Commander Steve Frick will be watching to see if Navy mission succeeds. "Go Navy," Frick told ABC News in an interview from onboard the space shuttle. "My pilot Alan Poindexter and I are both Navy guys and we are very interested in seeing how it goes."
The Pentagon has an eight-day window, beginning last Sunday, for shooting down the wayward satellite.
The Defense Department says the purpose of the shootdown is prevent chunks of the 5,000 pound satellite or any of its highly toxic fuel from raining down on cities or towns. But the $74 million mission has been dogged by doubts that the satellite poses any real danger, and that the true purpose is to test the Pentagon's ability to hit an enemy's satellite. The Pentagon denies that the attempted shootdown is a camouflaged weapons test.
When China used a missile to obliterate one of its own satellites last year, the U.S. protested, claiming the shards from the blasted satellite would pose a hazard to the International Space Station. That satellite was 500 miles above the Earth.
When the U.S. satellite-seeking missile is launched, the space station will still be orbiting Earth.
"I think NASA and the Defense Department love the station crew as much as they love the Atlantis crew," space station Commander Peggy Whitson joked.
The planned hit will take place when the satellite is orbiting just above Earth's atmosphere, so that most of the debris from the missile's destruction would fall out of orbit in just a few days, rather than continuing to orbit in space where it could be a hazard to the International Space Station and future shuttle flights.
If any debris does get close to the space station, flight controllers will move the orbiting outpost out of the way. They have done so six times in the space station's 10 years in orbit.
NASA'S Mission Control starts studying the possibility of performing a collision avoidance maneuver when the chance of collision reaches one in 100,000. NASA has an orbital debris group that is on call 24 hours a day if a satellite breaks up in orbit. They have put the odds of a collision with debris from the rogue satellite at one in 50,000 for the space station.