The first line of defense in America's next antimissile system fails or succeeds in a window of 90 seconds.
That's all the time there is, designers estimate, for a satellite to detect the flash of an enemy launch, determine that it is real and send off a counter-missile from the ground.
It all happens too fast to include a human in the loop.
"Time is of the essence," said Craig van Schilfgaarde, the Northrop Grumman Corp. engineer in charge of the project.
Known as "boost-phase" interception, it is designed to be the first "layer" of defense, firing rockets at enemy missiles just after launch, when they are most vulnerable.
The military has already deployed parts of the two other layers in the missile defense system -- one targeting missiles as they cruise through space in midflight and the other aimed at descending warheads when they are just above their targets.
For The Record
Los Angeles Times Saturday January 01, 2005 Home Edition Main News Part A Page 2 News Desk 1 inches; 48 words Type of Material: Correction
Missile defense -- An article in the Dec. 25 A Section incorrectly implied that the U.S. has begun to deploy defense systems that target warheads from intercontinental ballistic missiles after they reenter the atmosphere. That defense so far has been deployed only against short- and medium-range ballistic missiles.
The three layers are the cornerstone of President Bush's plan to defend the country against rogue nations, such as North Korea and Iran, that are gradually developing the ability to produce weapons with global reach.
But the system has already faced serious problems.
The midcourse missile failed a test Dec. 15 when it shut down before leaving its silo at the Ronald Reagan Test Site at Kwajalein Atoll in the central Pacific Ocean. It was the second failure in a major test in two years.
On Dec. 17, the Pentagon announced it was dropping plans to activate the existing pieces of the missile defense system this year because it had not completed full "shakedown" testing.
The boost phase reaches into an even more complex realm of design, in part because of the speed with which it must identify and destroy an enemy missile.
The payoff could be big. Terry Little, executive director of the government's Missile Defense Agency, said the boost-phase interceptors could destroy 80% to 90% of enemy ICBMs, leaving the other layers to take care of the rest.
But a recent Congressional Budget Office technical report suggested that the boost-phase system, scheduled for deployment in 2011, would press the far edge of what was physically possible in an antimissile system.
Philip Coyle, who headed the Pentagon's testing office during the Clinton administration, said the design of the boost-phase system was already buckling under its own complexity.
"The [congressional] analysis confirmed that boost-phase missile defense isn't practicable," Coyle said. "You can't fool mother nature."
Today's missile defense programs were inspired by President Reagan's promise to end "nuclear blackmail" with his Strategic Defense Initiative, a plan to shield the nation against an all-out nuclear attack using satellite-fired interceptors.
Dubbed "Star Wars" by opponents in Congress, Reagan's program fell victim to technical dead-ends, cost overruns and concerns that it would violate the 1972 Anti-Ballistic Missile Treaty, which banned nationwide missile defense systems.
Missile defense languished until 2002, when Bush withdrew from the treaty, which he considered a Cold War-era anachronism.
Instead of trying to defend against all-out nuclear attack by a major power, today's plan targets the less-advanced arsenals of emerging nuclear states.
The entire system is budgeted at about $50 billion over the next five years and is likely to cost several times that amount to build, deploy and maintain.
In July, the Missile Defense Agency began deploying the midcourse interceptors in Alaska. A second battery is scheduled for deployment next year at Vandenberg Air Force Base in Santa Barbara County.
Mobile Patriot antimissile systems, a key part of the descent layer (also known as the terminal layer), have been deployed.
A year ago, Northrop won a $4.5-billion contract to develop the boost-phase interceptors. Congress has approved $348 million for the current fiscal year.
Boost defense "would never be able to handle every situation that anybody could conceive of," said Little of the Missile Defense Agency. "But we could handle enough that we could look at ourselves as an 80% or 90% solution."
The allure of striking enemy missiles in the boost phase is that they are easily identified by their plumes just after launch and, because they are ascending, cannot use their full bag of tricks to dodge and deceive.
So far, the only part of the boost-phase system that has been built is a single camouflaged launcher with dual launch tubes. The 30-foot-long trailer is parked beside a pile of scrap metal outside a Northrop warehouse near Baltimore.
Little said that the system would not need the technical leaps that Star Wars required.
"The technology is in hand," he said. "It does not hinge on any kind of a technology breakthrough."
The trick is getting the pieces to work together -- all in the space of a few minutes at most.