The Technological Trap Beyond SALT

This text is from Strategic Survey 1977, published by the International Institute for Strategic Studies in London at the end of May. It appears in the chapter on “New Factors in Security.”


In recent years there has been increasing concern in the West about the future stability of the global strategic balance. The counterforce capabilities of both the United States and the Soviet Union are improving significantly, threatening the survivability of fixed strategic installations and challenging the role of the land-based components of national deterrent forces. By the mid-1980s deployment of the new technologies now being developed will seriously erode the second-strike capability of land-based missiles.

Although much of the recent debate has centered on this question, it may by then no longer be relevant. Not for many years has technological change been as volatile as it is at present. With many applications of new technologies under development, others “in the pipeline,” and still more being researched, it can no longer be assumed that the premises upon which the present strategic stability are based are assured.

Recent Developments

Of primary significance for the future of the strategic balance, at least in terms of the next ten to fifteen years, are a number of developments in strategic technologies—in engines, warheads, and guidance systems.

The greatly enhanced precision-guidance capacities which are now, or soon will be, available offer extraordinary accuracy. These guidance systems use for homing either those characteristics of a target which distinguish it from its surroundings (e.g., optical, infra-red, radio-wave, or acoustic signatures) or highly accurate navigation to strike fixed targets with known locations (or passing known locations) by such means as terrain contour matching (TERCOM), advanced inertial navigation systems, or navigation satellites.

Although both the United States and the Soviet Union have made progress in this field, American ballistic-missile guidance systems are generally considered to be a generation ahead of their Soviet counterparts. Judging from the varying estimates of accuracy that have been given, the current circular error probable (CEP) of the Minuteman III ICBM seems to be as low as 600-800 feet. Software improvements in the NS-20 guidance system, now being incorporated in all Minuteman III, will reduce this margin even further. The advanced inertial reference sphere (AIRS), a 10.3-inch diameter gimbal-less inertial guidance system being developed for the US Air Force’s MX ICBM, is expected to produce a CEP of around 200-300 feet, the lower figure probably being the limit attainable with purely inertial systems.

Although the United States is investigating the application of various techniques of terminal homing to ICBM, it seems doubtful, given these very low CEP, that they will increase accuracy enough to justify their deployment. By comparison, the CEP attributed to the latest generation of Soviet ICBM—the SS-17, SS-18, and SS-19—range from about 1,200 to 1,600 feet and are not expected to come below 1,000 feet until the early 1980s.

Increasing accuracy is also a feature of the American submarine-launched ballistic missile (SLBM) systems. The CEP of the Poseidon

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