The strange lights in the Santa Barbara sky last night were not indicative of the second coming. They were, however, the latest in a series of missile defense tests held at Vandenberg Air Force Base in north Santa Barbara County.

Last night’s test was the seventh missile defense test conducted by the Pentagon’s Missile Defense Agency, and the fifth one to end successfully. The trial was designated Integrated Flight Test-9 and was the first missile defense test to employ the Navy’s high-powered radar system. This system was only recently made available for missile defense tests after President Bush made the controversial decision to withdraw the United States from the 1972 Anti-Ballistic Missile Treaty and proceed with a National Missile Defense system.

Each test involves launching a missile with a fake or “dummy” warhead from VAFB. The missile enters suborbital space and releases its warhead, which is intercepted by another projectile known as the kill vehicle. The kill vehicle lifts off from Kwajalein Atoll 4,800 miles away in the South Pacific, a full 20 minutes after the VAFB launch. It homes in on the warhead via partial remote control and the use of a tracking beacon placed on its target. In a successful test, the 123-pound kill vehicle and the warhead finally slam into each other at a combined speed of 15,000 miles per hour somewhere over the Pacific.

Locally, Santa Barbara residents get their own spectacular show in the form of a starburst pattern in the evening sky. Soon after the Minuteman II intercontinental ballistic missile (ICBM) lifts off from Vandenberg, the first stage of the rocket is forcefully separated by a set of specialized explosives called shape charges. The stage is full of water, which condenses as a byproduct of the burning rocket fuel. The explosion disperses the water in a fine mist. The tiny water droplets freeze in the chill of the upper atmosphere and the mist cloud becomes a collection of tiny prisms that turn the last rays of dying sunlight into a rainbow in the night sky.

VAFB is the United States’ proving ground for ICBMs. Because of its location on a point on the West Coast, the base is capable of launching missiles and spy satellites into a polar orbit, which passes over the former Soviet Union. For this reason, the base became the cornerstone of the military’s “space coast.” In addition to ICBM and missile defense tests, government satellites and, more recently, commercial satellites are launched from VAFB.

The missile defense system is highly controversial. Many researchers consider the conditions of the tests to be unrealistic and dissenters who consider the project technically unfeasible include influential scientists from Berkeley Labs, MIT, Cornell, UCLA, University of Maryland, University of Pennsylvania and the US nuclear laboratories, along with former employees of Lockheed, the Rumsfield Commission and the Defense Science Board.

Other protesters point to the concept of leakage. The basic idea behind leakage is this: Say a foreign nation has one missile and you build a defense system to block it. For the same cost of your missile defense, the foreign nation can build ten missiles. If your system is a model of efficiency, it might be 90 percent effective, in which case after all your efforts, one missile would still get through.

Proponents of missile defense say the program will give the United States alternatives to nuclear retaliation in the event of an attack by a smaller nuclear nation.

The Pentagon will receive $8 billion in funds for missile defense in 2003.