How to bring down a spy satellite

February 19, 2008 9:33:15 AM PST
As soon as the space shuttle Atlantis is safely 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.

But the Navy is pretty confident it won't miss. Now the Navy will now be using only one ship to try to bring down a crippled spy satellite this week leaving in port two destroyers originally slated to assist in the mission. ABCNEWS has learned the first window to launch a missile at the satellite begins at 9:30pm ET Wednesday.

The Aegis cruiser USS Lake Erie is already at sea off the Hawaiian Islands and was always the primary ship in the mission. The destroyers USS Decatur and USS Russell will remain in their homeport of Pearl Harbor.

Pentagon officials had always expressed a high degree of confidence that the satellite could be brought down on the first try and that the other vessels will be there merely as back-up. The ships will continue to serve in the back up role, but will not put out to sea as part of the first attempt. Gen. James Cartright suggesting last week that there was an 80 to 90 percent chance of scoring a bull's eye.

Two Defense Officials also confirmed that the first window for launching an SM-3 missile at the spy satellite, known as USA-193, will be Wednesday night from 9:30pm to 12 a.m. ET.

The first hint of the window emerged when earlier this week when the FAA quietly sent an advisory warning ships and planes to stay clear of a large area of the Pacific Ocean west of Hawaii.

The $74 million mission is the first of its kind using technologies developed for the military's ballistic missile defense program.

Shuttle, Space Station Safety is Paramount

First, however, NASA must get Atlantis and its crew safely back on the ground. Officials don't fear that the shuttle will 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 space shuttle is expected to land, weather permitting, Wednesday morning in Florida or California. When the moment is right, a crew on the cruiser USS Lake Erie will fire a missile at the satellite.

Missile tests have taken place in the area in the past.

Why Now?

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.