A Less Tense World Doesn’t Eliminate the Need for Strategic Defense : SDI: The No. 1 reason to deploy remains the threat from the Soviet Union, still modernizing its most deadly nuclear weapons.

The Central Intelligence Agency estimates that by the year 2000 an additional 15 nations could have the capability to launch ballistic missiles.

Should there be a civil war in one of these nations, who would control the missiles? Who has the authority to launch them? Can one or more of the missiles fall into terrorist hands? What would America’s options be?

These questions underscore President Bush’s declaration on the importance of maintaining the Strategic Defense Initiative: “In the 1990s, strategic defense makes more sense than ever before.”

That bastion of stability, Col. Moammar Kadafi of Libya, recently asserted that Arab nations must develop nuclear weapons within the next several years. He also said, ominously, that if he had had nuclear missiles when U.S. planes attacked Tripoli in 1986, he would have retaliated by firing them at New York City.

It would be easy to dismiss such talk as the rantings and ravings of a madman. It would also be irresponsible. Kadafi and others like him have the resources and the will to carry out their threats.

But the No. 1 reason to deploy a strategic defense system remains the military threat posed by the Soviet Union. True, our relationship with Moscow has never been better. But the Soviets maintain an enormous military capability. And that capability is getting stronger where it is most threatening--in strategic nuclear weapons. Despite reducing conventional forces and cutting defense spending, the Soviets are still pursuing a major strategic modernization program.

Last year, the Soviet Union produced 140 new ICBMs to our 12. Why, in this emerging age of easing tensions, do the Soviets feel a need to increase their strategic nuclear weaponry?

Some believe that perestroika has made the Soviet Union more dangerous to the United States than ever before. The stability of its leadership can no longer be assumed. Soviet Foreign Minister Eduard A. Shevardnadze hinted as much in a statement that caught many Western analysts by surprise. He warned that Soviet hard-liners, eager to exploit Mikhail S. Gorbachev’s unpopularity at home, may try to ignite a “social explosion” that could bring into play the Soviet Union’s nuclear and chemical weapons.

Whatever the Soviets’ current thinking, the mission of the Strategic Defense Initiative Organization must remain unchanged--to kill ballistic missiles.

Should a nation launch a ballistic missile at the United States, accidently or otherwise, the President has only two options: He can let it hit, then do nothing; or he can retaliate in kind, thereby risking full-blown nuclear war. Neither option should be acceptable. That is why it is essential to the security of the United States that the President be given a third option--a fully functional and deployed strategic defense system.

To date, more than 400 experiments have demonstrated that the United States has the technology to deploy such a system. The progress we have made toward this goal is nothing short of phenomenal.

--In 1984, using a ground-launched missile, we successfully hit a simulated nuclear warhead by tracking its thermal signature. The closing velocity was greater than 14,000 feet per second. It was like hitting a bullet with a bullet.

--In 1987, a tactical missile, traveling at three times the speed of sound, was intercepted in the atmosphere by a ground-launched missile.

--A computer performing 1 billion operations per second can add all the country’s Social Security numbers in one-fourth of a second. The computer we use can carry out 40 billion operations per second.

--In 1988, we successfully demonstrated that a laser beam, directed at the casing of a ballistic missile, can destroy the missile.

--An experiment is now under way to show that a ground-based laser beam can be relayed from a space-based mirror and hit a target a few meters in size at a range of 300,000 meters.

--Early this year, a laser-radar experiment called “Firefly” successfully tracked and identified, in a matter of microseconds, a re-entry vehicle decoy at a range of 800,000 meters. This outcome demonstrated that we can, despite what the critics insist, distinguish a decoy warhead from the real thing.

--The most promising strategic defense system is called “Brilliant Pebbles.” Each “pebble” is a self-contained ICBM killer, with integrated sensors, guidance, control and battle management. Simply put, each pebble is a small (it would fit on a coffee table) space-based interceptor that kills a missile by ramming into it at a high rate of speed. In many respects, a brilliant pebble is a space-based version of an air-to-air missile that is mounted on a radar-equipped aircraft.

There are many more success stories, enough to put the goal of the Bush Administration, the Department of Defense and the Strategic Defense Initiative Organization well within reach--to deploy a few thousand “Brilliant Pebbles” in orbit around the Earth. In peacetime, the Brilliant Pebbles would act as highly sensitive sensors; in the event of a ballistic-missile launch, accidental or not, they would, once given the command, destroy the missile in the boost and post-boost phases of its flight.

We now spend more than $5 billion a year not to grow crops. The 1991 SDI budget request is $4.6 billion. Isn’t spending money to protect ourselves, our children and grandchildren from the horrifying effects of a ballistic-missile attack a better investment?