A Trio to Tax Any Negotiation

Intermediate-range nuclear missiles are understandably of more urgent concern to U.S. allies in Europe and to the Soviets than to the U.S. itself. Such missiles are designed to fly no more than 3,000 miles, which puts all U.S. territories except westernmost Alaska out of their range. Most Soviet citizens and every European, however, are vulnerable. To make intermediate-range missile negotiations even trickier, the bargaining that resumes this week in Geneva concerns reductions in a Soviet arsenal already in service, while the NATO missiles that might be cut are yet to be deployed.

There are principally three types of missiles under discussion in Geneva: one Soviet and two U.S. The Soviet missiles are probably targeted on military sites; similarly, the Western missiles would be aimed at the Soviet missiles and other military targets.

Soviet SS-20. The SS-20 is the biggest of the three (36 ft. tall, 5 ft. 6 in. in diameter). Unlike its Soviet liquid-fueled predecessors, which are considerably less accurate, the SS-20 is propelled by solid fuel. The main advantage: liquid fuel cannot be stored in a missile and the fueling process is slow. All U.S. missiles use solid fuel. The SS-20's range is long, up to 3,000 miles, and it is mobile, which makes it harder to find and destroy. Each has its own launcher, and Western intelligence experts suspect there is room for a second reload missile inside; the launcher runs under its own power on tank treads or tires. The missile is MIRVed, carrying three 150-kiloton warheads, each with its programmed target. The SS-20 is a replacement for the antiquated SS-4 and SS-5, which nevertheless remain deployed and are under negotiation in Geneva. The Soviets have deployed some 340 SS-20s in the past six years--a rate of more than one a week--scattered over 38 sites. Two-thirds are west of the Ural Mountains, pointing westward with at most a 20-min. flight to West Germany. Sums up a Bonn defense official: "There is no Soviet weapons system in its class that comes close to matching the SS-20." A compatriot in the Foreign Ministry agrees. "The SS-20," he says, "is a unique threat."

U.S. Pershing II. Until last Friday morning, the new Martin-Marietta missile had not had a successful test flight. A skeptical Congress has authorized funds only for the first 21 missiles; the Pentagon hopes to build 108, at a total cost of $2.8 billion. All are destined for West Germany, where they will replace shorter-range Pershing Is that have been there since 1969. The Pershing II's range of 1,000 miles means it cannot reach Moscow from West Germany, but it can land its 250-kiloton warhead (15 times the Hiroshima bomb) in many parts of the western U.S.S.R. in less than ten minutes. Like the SS-20, it is propelled by solid fuel in two stages. Not quite so tall and much slimmer (32 ft. 9 in. by 3 ft. 3 in.) than its Soviet opposite, the new Pershing is theoretically ten times as accurate, able half the time to hit within 30 yds. of its target. Once the warhead is diving earthward, its "radar area correlator" kicks in, comparing the actual terrain below with a map stored in its small computer, and moving external fins to bring the warhead down precisely on target. This complicated "terminal guidance system" failed to work properly during last November's test flight. It is not as mobile as the SS-20, but its extreme accuracy is of great military value against such vital hardened targets as an enemy's communications centers. It is probably the weapon that most worries Soviet military strategists.

U.S. Tomahawk cruise missile. The SS-20 and the Pershing II are ballistic missiles: they fly in an arc like an artillery shell. The Tomahawks are more like unmanned jet planes; indeed, they are designed to replace piloted bombers. The comparatively petite (18 ft. long, 2 ft. 3 in. wide) cruise missiles are loaded four to each wheeled launcher, with four launchers clustered at each site. Britain is to have ten such sites, Italy seven, West Germany about six, Belgium and The Netherlands three each. The cost for the 464 missiles: $3.7 billion. Tomahawks have a drawback: they are slower than most jet planes. At a cruising speed of about 500 m.p.h., a Tomahawk would take three hours or more to fly its 200-kiloton warhead from England to a Soviet target. The missile's advantages: stealth, remarkable mobility and accuracy. A cruise missile can skitter along between 50 ft. and 200 ft. above the ground and, guided by a preprogrammed computer map similar to that on board the Pershing II, strike within 10 to 20 yds. of its target. This file is automatically generated by a robot program, so viewer discretion is required.