Over Our Heads

Gaze out on Everett's Port Gardner Bay and imagine a 250-foot-high sphere, something like an astronomical observatory or a mutant golf ball, perched on the edge of a floating 400-foot-long rig. The mystery object, which could really start going up as soon as next year, is called the Sea-Based X-Band Radar, and it's a crucial component of President George W. Bush's Ballistic Missile Defense program.

The Pentagon will decide this August whether this vision will come true. The other sites in competition are in Hawaii, the Marshall Islands, California, and Alaska. A few environmental groups have filed protests, noting the damage that might be done by such powerful radar beams. The Pentagon's environmental impact statement denies this claim. The big ball will be in port for less than half the year. (Most of the time, it will be on station out in the Pacific Ocean.) While in port, the radar will be turned on for 20 to 60 minutes a day. At 150 meters (the closest anyone can come to the dock at those times), the effect will be the same as standing two inches from a microwave oven.

The larger debate, which has been heard far less, involves the program itself. Missile defensethe ability to shoot down an enemy's nuclear missiles after they're launched and before they land and explodeis a dream that nuclear war planners have been conjuring for nearly half a century. But no president has taken it more seriously or brought it closer to reality than Bushnot even Ronald Reagan, whose utopian vision of a nuclear shield inspired the derisory nickname "Star Wars."

The military budget that Congress passed earlier this year allocates $9.1 billion to missile defense, a 20 percent hike over the amount approved last year and three times the annual levels spent at the peak of Reagan's heyday.

Bush also did what many conservatives had only fantasized about doing for 30 yearshe pulled out of the 1972 ABM Treaty, which, besides forming the centerpiece of U.S.-Russian arms-control agreements, banned the deployment (as well as sharply restricted the research and development) of anti-ballistic-missile weapons. Last December, when he ordered Defense Secretary Donald Rumsfeld to start deploying a system, he called the move "an essential element of our broader effort . . . to meet the new threats we face," and added that "defending the American people against these new threats is my highest priority."

THREE-PART HARMONY
Bush's program is far more elaborate than any previous incarnation of the concept. If ever completed (and there is much doubt about this), the system would be divided into three segments, each consisting of hundreds or thousands of parts, all acting in tandem.

The first segment of the program involves "boost-phase intercept." Satellite-based radars detect a missile being launched. Then lasers, fired from other satellites or from a specially equipped Boeing 747, shoot the missile down in the three to five minutes that it rises through the sky, before it clears the atmosphere.

Second is the "midcourse intercept," the 20-minute phase when the enemy's missile arcs through outer space. In the Pentagon's most widely discussed scenarioa North Korean missile aimed at America's West Coastthis would be the phase when it crosses the Pacific Ocean. Or, on the threat boards of an earlier era, it was when Soviet missiles flew over the North Pole, then down across Canada, toward any number of possible "aim points." In this phase, various devicesspace-based, ship-based, air-based, and ground-based "kill vehicles," all guided by highly sophisticated radarswould try shooting the missile down before it gets close to our shores.

Third is the "terminal defense," the final 30 seconds when the missile's warhead plunges back down into the atmosphere toward the target, and when U.S. anti-missile missiles make a last-ditch effort to destroy the weapon before it explodes.

The boost-phase intercept is, in some ways, the easiest. As a rocket ascends toward space, it moves slowly, straight up, with engines burningabout as vulnerable a target as might be imagined in this realm. In another way, though, it's the hardest phaseyou have to know where the missile is being launched, and the sensors and lasers need to be orbiting overhead at all times.

Terminal defense might be thought a fairly straightforward task. Computerized radars extrapolate from launch data where the warhead will be landing; fire-control systems then automatically aim the weapons in that direction; and bang! you've got him. As we learned from the first Gulf War, though, it was very hard for Patriot air-defense missiles to shoot down Iraqi Scuds (postmortem analysis indicated only a 9 percent success rate). As we learned in the second Gulf War, the computers in even the newest-generation Patriots have a tendency to mistake British war planes for Scuds. (They shot down a British Tornado and an American F18, and would have downed an American F16 as well, except that the F16 pilot, seeing that his plane was being "painted" by the Patriot's radar, fired an anti-radar missile at the missile batteries and destroyed them in the nick of time.) And Scuds are much slower, bulkier, and shorter-ranged than the warheads to be shot down in Bush's multilayered missile defense system. (Nor are we talking apples and oranges here: The new Patriots just used in Gulf War II, the PAC-3s, are to be among the interceptors in this system's terminal-defense phase.)