Foreign Relations of the United States, 1969–1976, Volume XXXIV, National Security Policy, 1969–1972

226. National Intelligence Estimate¹

NIE 11–3–72

Washington, November 2, 1972.

SOVIET STRATEGIC DEFENSES

Summary and Conclusions

A. Despite a sustained and costly effort over the past several decades, Soviet progress in developing strategic defenses has not matched progress made in offensive capabilities. The Soviet agreement to the Treaty on the Limitation of Antiballistic Missiles (ABMs), in effect, indicated recognition of this situation. The Treaty will, of course, have a major impact on future Soviet defensive developments, and, as we point out below, we do not expect the Soviets to develop systems or forces capable of overcoming the offensive lead.

B. Soviet defenses against ballistic missile attack are negligible and show no prospect of becoming effective against a major attack; the Treaty specifically limits missile defenses. There is no evidence that the Soviets will in the next decade be able to negate the threat posed by Western nuclear-powered ballistic missile submarines (SSBNs). And Soviet air defenses, which already have problems in dealing with low-altitude attacks, face the prospect of further degradation as the US deploys new air-to-surface missiles (ASMs) on present and proposed aircraft.

Air Defenses

C. Soviet air defenses had, as of 1 October 1972, some 4,000 ground-based radars at 1,000 radar sites, 3,000 interceptor aircraft, and over 10,000 surface-to-air missile (SAM) launchers at some 1,100 sites and complexes. These defenses are deployed in barriers, across the main approach corridors, and around key centers. The defenses are integrated into an air defense system which increasingly uses automated techniques for faster and more effective control.

D. These integrated forces provide a formidable defense against aircraft and large radar cross section aerodynamic ASMs penetrating at medium and high altitudes in all weather conditions. This capability could, however, be degraded by use of electronic countermeasures, defense suppression, and proper selection of penetration routes and altitudes. Capabilities are extremely limited against low-altitude (below 1,000 feet) penetrations and almost non-existent against attacks by higher velocity, low radar cross section ASMs like the US short-range attack missile (SRAM).

E. Defense against low-altitude attack is made difficult by the fact that the attacking aircraft or ASMs are hard to detect and track, particularly against the background of ground clutter. Soviet air surveillance below about 1,000 feet is spotty at best. We expect the Soviets to continue to improve their low-altitude radar coverage by increasing the number of ground radar sites and by installing more mast-mounted radars. In addition, we continue to believe that they will develop an airborne warning and control system (AWACS) with an overland look-down radar in the late 1970s or thereafter.

F. We also believe that the Soviets could develop an advanced long-range, all-weather interceptor with a look-down, shoot-down capability by the late 1970s. Such an aircraft would complement the overland AWACS. But they may not wait until the late 1970s before deploying a new fighter. While unlikely, they could bring in a new low-altitude fighter, based on an existing model, in the mid-1970s.

G. At the present time the Soviets have no defensive system which could reliably engage an ASM such as SRAM. Only the SA–5 utilizing a nuclear warhead could have a very limited capability against SRAM. To meet this threat the Soviets may attempt further to improve SAM systems already deployed, although this does not appear to be the most effective option for them. However, if attempted, it would have to be done without giving the appearance that the SAMs were being upgraded to perform a ballistic missile defense mission as prohibited in the Treaty. On the other hand, the Soviets might design a completely new SAM system which would be capable of engaging both ASMs and aircraft penetrating at low altitudes. To be effective, such a weapon system would have to be widely deployed and would require integration with new, more efficient surveillance and command and control systems.

Ballistic Missile Defense

H. The Soviets have installed a ballistic missile early warning system on the periphery of the USSR and an ABM system around Moscow. This ABM system would be susceptible to saturation and exhaustion. It cannot discriminate between re-entry vehicles (RVs) and penetration aids outside the atmosphere, and the lack of high acceleration missiles prevents it from waiting for atmospheric sorting after the threatening objects enter the atmosphere.

I. The Moscow System’s nominal 300 nautical mile (nm) range gives it an inherent capability to defend regions outside the Moscow area. With only 64 launchers and no provision for rapid reload, the defense would be thin. Used to protect the immediate Moscow area, and utilizing a shoot-look-shoot technique, the system could probably be effective against about 45 targets—including RVs and penetration aids. Thus, the defense would at best be effective against an accidental or unauthorized launch or against a small, third country attack.

J. The present limitations of the Moscow System and continuing ABM research programs at Sary Shagan suggest that the Soviets will want over the next decade to improve and fill out the Moscow defenses to the 100 launchers allowed under the Treaty. If such improvement starts soon, a new exoatmospheric system (ABM–X–2) under development at Sary Shagan would be the most likely candidate. It would provide a greater target handling and engagement capacity, but would, of course, still be of limited capability.

K. The Soviets are also developing another ABM system (ABM–X–3) at Sary Shagan. The first sites could be deployed rather quickly (on the order of a year from start of construction to initial operational capability), although widespread deployment might require 5 years or more. This system could, without the addition of an appropriate long-range acquisition radar, provide a thin defense against RVs which exhibit large radar cross sections and re-enter the atmosphere relatively slowly (such as Polaris or postulated Chinese RVs). Defense against more sophisticated weapons (e.g., Poseidon or Minuteman) would require an interceptor with much higher acceleration. Even so, if deployed in the near future, this system seems at present to be the best candidate for defense of an area containing intercontinental ballistic missiles as allowed under the Treaty.

Defense Against Ballistic Missile Submarines

L. The Soviets have demonstrated no capability to detect US SSBNs on patrol in the open ocean. The USSR has no equivalent to the US sound surveillance system and thus cannot keep track of patrolling SSBNs by this method. Further, Soviet submarines are not able to trail US SSBNs covertly (using passive sonars) because of the noise advantage enjoyed by the US submarines. The Soviets have not attempted to maintain overt trail (using active sonars) on patrolling SSBNs, and we believe that if they did they probably could not maintain it for extended periods. Nor is open ocean search by Soviet ships, submarines, and aircraft effective against SSBNs.

M. We do not anticipate that the Soviets will arrive at any fundamental solution to detecting US SSBNs within the decade. The basic difficulty of detecting SSBNs on patrol in the open ocean will remain. We do, however, expect the Soviets to improve their acoustic detection devices, to install them on ships and submarines, and perhaps to deploy, in limited areas, some improved fixed acoustic arrays and moored buoys. Even though the Soviets will reduce the noise levels of their submarines, the noise advantage enjoyed by US SSBNs is such that, as a force, they will not be vulnerable as a result of these improvements during the 10 year period of this Estimate.

N. We expect the Soviets to improve their magnetic anomaly detection capability and to develop other non-acoustic detection methods. However, they would still face the problem of integrating the non-acoustic detection techniques into their antisubmarine warfare forces, and none of the better understood methods appears to offer a solution to the problem of submarine detection in the open ocean.

Antisatellite Defense

O. Since 1968, the Soviets have been conducting an active orbital intercept program. They have demonstrated on at least seven different occasions that they are capable of engaging satellites in orbit at altitudes between 100 and 600 nm. On the basis of these tests, we believe the Soviets can conduct non-nuclear attacks on satellites below about 1,000 nm. Use of a powerful enough launch vehicle might permit them in the future to engage satellites at geostationary (19,300 nm) altitudes. Another approach available to the Soviets would be to use the Galosh ABM interceptor to conduct non-nuclear attacks on satellites up to 300 nm and perhaps as high as 450 nm, although at this altitude a nuclear warhead might be required.

P. Considering the importance of space reconnaissance to the viability of the Strategic Arms Limitation Talks agreements, we continue to believe it highly unlikely that the Soviets would actively interfere with US satellites. They have agreed in the Treaty to Limit ABMs and the Interim Agreement on Offensive Missiles not to interfere with national means of verification. They also would not wish to cause US retaliation against their own considerable satellite reconnaissance program.

Future Force Development

Q. The development of the future Soviet strategic defense force structure will be heavily influenced by the Treaty on Limitation of ABMs and the Interim Agreement on Offensive Missiles. The ABM Treaty has the more immediate and direct impact, but the Interim Agreement on Offensive Missiles is particularly significant to this Estimate in that it does not limit aircraft or missiles delivered by aircraft. The agreements at one and the same time simplify and complicate estimates of future Soviet strategic forces. They simplify by permitting force projections in line with the agreements, as in the case of ABMs. But they complicate by raising the question of under what conditions the agreements might be terminated, and what force deployments might occur after such a break. And future Soviet defensive forces will not only be affected by the interaction of momentum and constraints in the USSR on the development, production, and deployment of successive generations of new weapon systems, they will also be sensitive to the course of negotiations with the US. The developing Chinese strategic threat to the USSR is also a complicating factor in assessing the future developments in Soviet strategic defenses.

R. If the Soviets believed the prognosis to be favorable for further agreements between the US and USSR to limit strategic arms, they would probably build their strategic defenses more slowly than in the past. In fact, if they judged that the US would eventually reduce its forces, they might do little more than complete programs underway and continue essential R&D activities. More likely, they might feel impelled to continue to improve their defenses across the board within the limits of the present agreements in order to enhance their security vis-à-vis the US and the People’s Republic of China and to improve their bargaining position in the strategic arms limitation negotiations.

S. The Soviets might, of course, be prepared to stop negotiations and terminate existing agreements if they came to believe that their security or position of equality with the US were threatened. In this case, the Soviets might build up permitted systems while the Treaty was in effect and prepare to deploy additional systems after 1977. Or negotiations might deteriorate to the extent that they or the US would withdraw from the Treaty prior to 1977 and embark upon a more intensive buildup.

T. We have, in Section IX of this Estimate,² postulated four force models which illustrate a range of possible defensive deployments under differing conditions during the remainder of the decade.³ Force Models I and II illustrate deployments the Soviets might undertake within the terms of the ABM Treaty. Model I represents a minimum effort in which little is done beyond completing programs already in progress. Force Model II illustrates a greater level of effort, but deployments are still within the limits of the ABM Treaty. Force Models III and IV illustrate different postures the Soviets might adopt if the Treaty were terminated. Model III is representative of a continuation of the arms competition as it was before the limitation agreements, while Model IV illustrates a maximum defensive effort short of actual war.

U. Force Models I and IV represent a low and a high level of effort, respectively; both are quite feasible under the assumptions given, but we consider them to be unlikely extremes. We believe that Force Model II represents a likely level of effort and technical progress. It assumes that the US and the USSR would continue present strategic arms limitation agreements and reach new ones, and that neither country would have to contend with a third country threat so great as to cause withdrawal from the agreements. On the other hand, if further agreements are not reached, and the ABM Treaty were to be terminated in 1977, the Soviets might build defenses roughly equivalent to those shown in Force Model III. But we wish to emphasize that these models are strictly illustrative, and not to be regarded as confident estimates or as projections for defense planning. As one moves beyond the next 2 years or so, all projections become increasingly uncertain; beyond 5 years they are highly speculative.

[Omitted here is the 65–page Discussion portion of the estimate including the following sections: I. The Soviet Approach to Strategic Defense, II. Strategic Air Defense, III. Defense Against Ballistic Missiles, IV. Strategic Defense Against Submarines, V. Antisatellite Defense, VI. Soviet Civil Defense, VII. The Framework of Future Soviet Strategic Defensive Policy and Planning, VIII. Development and Deployment of New Defensive Systems, and IX. Illustrative Future Forces. Omitted also are a Glossary and 28 pages of Tables of Estimated Characteristics and Performance.]

1. Source: Central Intelligence Agency, NIC Files, Job 79–R01012A. Top Secret. The Central Intelligence Agency and the intelligence organizations of the Departments of State and Defense, the NSA, and the AEC participated in the preparation of this estimate. The Director of Central Intelligence submitted this estimate with the concurrence of all members of the USIB with the exception of the representatives of the FBI and the Department of the Treasury, who abstained on the grounds that the subject matter was outside their jurisdiction. The table of contents is not printed. The full text of this NIE, excluding the glossary and tables of characteristics, is in the CIA FOIA Electronic Reading Room (www.foia.cia.gov).
2. Section IX discusses Illustrative Future Forces.
3. Vice Adm. Vincent de Poix, USN, the Director, Defense Intelligence Agency; Maj. Gen. William E. Potts, the Assistant Chief of Staff for Intelligence, Department of the Army; and Rear Adm. Earl F. Rectanus, the Director of Naval Intelligence, Department of the Navy, are in fundamental disagreement with several aspects of Section IX. For their views see their footnotes throughout that Section. [Footnote in the original.]