I call upon the scientific community who gave us nuclear weapons to turn their great talents to the cause of mankind and world peace; to give us the means of rendering these nuclear weapons impotent and obsolete.
- President Reagan, March 23, 1983
President Reagan's call for a way to defend against nuclear weapons has created a fur-flying catfight among scientists and strategists.
Experts with impressive academic and professional backgrounds (and presumably good intentions) have reacted with wildly different assertions about whether an advanced means of nuclear defense - largely from space - would work.
In one sense, this should not be surprising. Mr. Reagan's strategic defense initiative is radical in at least two ways. It not only challenges the very basis of United States strategic doctrine in place for most of the nuclear age. It also is one of those rare instances where strategy (at least proposed strategy) leads, rather than lags, technology.
In other words, the President has suggested something that cannot yet be proved possible. He has acknowledged that ''it will take years, probably decades , of effort,'' and that this no doubt will include ''failures and setbacks'' as well as ''successes and breakthroughs.''
Supporters call this visionary leadership, since the decision to deploy defenses in space will be made by future presidents. Detractors say the concept is dangerous, if not ''preposterous.''
At the moment, the weight of scientific opinion - at least from those most vocal experts - is against the notion of comprehensive strategic defense.
''In my opinion, the whole thing is a house of cards,'' says physicist Richard Garwin, a defense analyst and consultant to business and government on nuclear weapons and strategies. ''It is totally infeasible to produce the kind of defense that the President called for. There's not a chance that we'll be able to build a system which cannot be countered by the Soviet Union, a system which would defend society.''
Dr. Garwin is strongly rebutted by physicist Robert Jastrow, former director of the Goddard Institute for Space Studies and now a professor at Dartmouth College in New Hampshire. Dr. Jastrow calls the assertions of Garwin and others in a report by the Union of Concerned Scientists (UCS) ''irresponsible ... shoddy ... a great disservice ... filled with errors that can only be called inane.''
''All the errors in the criticisms offered by the President's scientist critics have the effect of greatly exaggerating the technical problems ... while at the same time minimizing the difficulties that would be encountered by the Soviet Union in devising countermeasures,'' says Jastrow. ''When these errors are corrected, the President's plan ... is seen to be basically sound and offers a great promise of delivering the American people from the threat of nuclear attack.''
Earlier this year, the UCS examined the technologies that would be involved in a leak-proof space-based missile defense and pronounced the problems ''intractable.'' This group, which included a long list of prominent scientists (including two Nobel laureates), warned that no matter what the US did to fashion a defense against nuclear attack, the Soviet Union could more easily and cheaply counter it with protective or deceptive measures, or simply overwhelm a defensive system with more nuclear warheads.
For example, the UCS concluded that during the boost stage of an attack, 2, 400 space-based lasers in orbit would be needed to counter all 1,400 Soviet intercontinental ballistic missiles, since most of these satellite weapons would be out of range of Soviet missile fields at any given time. The group also said it would cost $60 billion to station enough homing ''kill vehicles'' in space to target every attacking ICBM.
The UCS later revised these estimates by large factors down to 300 laser weapons and $13 billion for the kinetic energy antimissile weapons, but asserted that ''these changes do not affect the principal findings and conclusions stated in the report.''
Others (including some opponents of the strategic defense initiative) say it would take even fewer satellite-based lasers to defend against enemy missiles. Sen. John Glenn (D) of Ohio put the number of necessary satellites at 240. In a report for the congressional Office of Technology Assessment, Ashton Carter of the Massachusetts Institute of Technology said 160 satellites (assuming current Soviet missile hardness and rocket flight time) would be adequate. Dr. Jastrow, drawing on the work of Defense Department scientists, says fewer than 100 would be needed.
MIT physicist Kosta Tsipis figures it would take 50-to-100 hydrogen fluoride lasers to continuously target 1,000 Soviet missiles. But he estimates that carrying all the necessary laser fuel would require from 100,000 to 200,000 flights of the space shuttle. Dr. Tsipis also says a few large nuclear explosions at high altitude could ''blind'' the ground-based radars that would be part of the final stage of strategic defense.
''Frankly, that's a little naive,'' retorts Lt. Gen. James A. Abrahamson, director of the Strategic Defense Initiative Office. General Abrahamson says the task of wiping out a defense system's command and control facilities would be much more difficult than that, but he acknowleges that the research he overseas includes the possibility of enhanced radiation by an attacker.
Critics also say the Soviet Union could simply coat its missiles with a thin layer of lead paint to shield against particle beams. Dr. Jastrow contends that it would take a one-inch-thick ''lead casket'' weighing many tons, with the result that ''their missile would be so loaded down with lead that it would be unable to carry any warheads.''
No matter what scientists discover in coming years, such assertions and rebuttals will have to remain in large measure theoretical. Unlike test firings of strategic missiles (such as the US MX or Soviet SS-18), there is no way to find out - in advance of nuclear war - how well a missile defense system would work.
''If the system is to meet the President's stated goal of rendering nuclear weapons 'impotent and obsolete,' not only must it work to almost 100 percent perfection, managing an enormous task of battle management in very short times, but it must do this the very first time that it is used,'' says physicist Sidney Drell of Stanford University. ''No realistic shakedown tests are conceivable, especially in the nuclear environment the system will encounter in a real engagement. This is a preposterous requirement.''
As Dr. Tsipis pointed out in a detailed study several years ago, great uncertainty also exists about whether an attacker's nuclear first strike would succeed. Supporters of strategic defense say this increased uncertainty about being able to strike first - or defeat such an attack - adds to deterrence and reduces the likelihood of nuclear war.In any case, clearer answers will be some time in coming. Lowell Wood of the University of California's Lawrence-Livermore Laboratory, where much of the advanced research is going on, says:
''Neither I nor anyone else can truthfully tell you that strategic defense will eventually be seen to be technicaly feasible, let alone tell you when or at what cost. Similarly, no one can honestly assure you that it will not work, or that it won't work sufficiently well, or that its cost will be prohibitive.
''It has taken us a third of a century and trillions of dollars to work our way into this mess,'' Dr. Wood adds. ''And getting out of it probably won't be exceedingly cheap and probably won't occur terribly quickly.''Next: Strategic defense and arms control.