MISSILE DEFENSE DETAILED

The first phase of America's missile defense system is about to come online. And the New York Times' James Glanz travels to Delta Junction, Alaska to profile the emerging -- and controversial -- effort.

The first system will rely on interceptors in a handful of silos here at Fort Greeley, an Army base, and at Vandenberg Air Force Base, Calif. In an attack, boosters would release the kill vehicle more than 100 miles above earth. With a heat-sensitive telescope, the vehicle would search the chill of space for the warhead, then maneuver with its thrusters and try to pulverize the weapon by simply ramming it at speeds faster than 20,000 miles an hour.
Even that description does little justice to the complexity of the system, which spans nine time zones and uses 13,000 miles of fiber optics to link sites as varied as a radar installation on the bleak island of Shemya in the Aleutians and in a secret command center at Cheyenne Mountain, Colo. If it works as planned, the system may take the honorary title of the biggest machine ever built from the nation's electrical grid.
As the nation discovered in the blackout last summer, of course, large machines can be unpredictable. The missile defense system, in fact, is so enormous and complex that it may never be fully tested unless an attack occurs.