178. National Intelligence Estimate1

NIE 11–3–71


Summary Conclusions

I. The Present Status of Soviet Strategic Defenses

A. Confronted for many years with a strategic threat from the US much greater in size and complexity than that which the US faced from the USSR, the Soviets have regularly expended greater resources on strategic defense than the US. Consequently, they have deployed the most extensive and, in some respects, most modern strategic defenses in the world. This Estimate treats mainly those Soviet forces designed to defend the USSR against manned bombers and their air-to-surface missiles (ASM), against ballistic missiles, and against ballistic missile submarines in the open ocean. Briefer treatment is given to Soviet capabilities to render inoperable or destroy satellites in orbit, and to civil defense.

B. As total Soviet outlays for military and space programs grew during the 1960s by some 50 percent, the proportion devoted to strategic defense remained constant at about 15 percent. (This compares to about 15 percent for intercontinental and peripheral strategic attack, 25 percent for general purpose forces, and 45 percent for command and general support, research and development (R&D), and space programs for the decade of the 1960s as a whole.) Of the share for strategic defense, about 75 percent went to air defense, 5 percent to ballistic missile defense, and the remainder to antisubmarine warfare (ASW).2 Expenditures for these defenses in 1970 approximated 3 billion rubles [Page 725] (the equivalent of about $9 billion).3 These figures, however, represent only the cost of producing, deploying, and operating already developed weapons systems. They do not include amounts allocated to R&D, which we cannot quantify, but which are very substantial, and are especially significant in the fields of ballistic missile defense and ASW.

Air Defense

C. As a result of this effort, we estimate that the Soviets had on 1 January 1971 a strategic air defense establishment with some 3,300 ground-based radars, 3,300 interceptor aircraft, and over 10,000 surface-to-air missile (SAM) launchers at 1,200 sites. During the past few years they have introduced new automated techniques in order to control these forces more rapidly and effectively. The airborne warning and control (AWAC) aircraft, Moss, is now believed to be operational and capable of limited overwater patrols for early warning, and probably airborne interceptor control. Their integrated systems provide excellent defense against bomber attacks at medium and high altitudes. Defense against current air-to-surface missiles (ASMs) at these altitudes is almost as good.

D. The Soviets still have not solved fully the problem of intercepting aircraft coming in at low altitudes. Soviet capabilities against aircraft flying below about 1,000 feet remain limited, although gradual improvements have continued over the past several years. For example, in the Leningrad area ground-based radars on masts probably can now provide continuous tracking of an aircraft flying as low as about 200 to 300 feet. The SA–3 has been modified to permit intercepts down to about 300 feet, and deployed more widely. Some models of the SA–2 may also now be able to intercept at altitudes as low as 300 feet in favorable locations, although 500 to 1,000 feet is a more general low-altitude limit. The Firebar interceptor aircraft can attack targets down to about 600 feet, and perhaps somewhat lower over water and flat terrain. To engage penetrating aircraft at such low altitudes with a variety of weapons, however, puts a very heavy burden on the command and control network.

Ballistic Missile Defense

E. During the past eight years the Soviets have installed a ballistic missile early warning system on the periphery of the USSR and an antiballistic missile (ABM) system around Moscow. Additional early warning radars are still under construction, and an improved ABM system is under development at Sary Shagan. The Moscow ABM system is not yet maintained at a high state of readiness. Tests of the Galosh [Page 726] interceptor missile show that it can attack an incoming missile either outside the earth’s atmosphere at long ranges, or within the atmosphere at much shorter ranges; the use of both modes against a single target allows a two-layer defense with an improved probability of success. But the system cannot discriminate between re-entry vehicles (RVs) and decoys and chaff outside the atmosphere. Moreover, since the interceptor missile does not have very high acceleration (unlike the US Sprint), it cannot wait for the sorting of RVs and penetration aids by the atmosphere before being launched.

F. Assuming optimum conditions, our theoretical calculations indicate that the Moscow ABM system, using a two-layer defense, could at best successfully engage about 45 ICBM targets before running out of interceptor missiles. Decoys and chaff puffs would appear as valid and separate targets, and their use could rapidly exhaust the missiles on launcher. The system could handle an equal number of submarine-launched ballistic missile targets if they arrived from sectors covered by large acquisition and tracking radars. In an attack from other directions, however, such as from the western Mediterranean, the defenses would have to rely on engagement radars at the missile sites for acquisition of targets and could be saturated by a relatively light attack.4

G. Because of its long range, the Moscow system has an inherent capability to defend regions outside the Moscow area, but it can protect such regions with only a single layer, and therefore quite thin, defense. This area defense would be more effective against attacks by a small third country or an accidental or unauthorized launch, as the number of targets would be small, and several interceptor missiles could be sent against one target. The ability of the Moscow system to protect Moscow and its environs from a moderate, unsophisticated attack, and its ability to defend a much larger area against a light attack, make it well suited to the National Command Authority (NCA) type of defense which has been proposed at the strategic arms limitation talks (SALT).

H. There is ample evidence that currently deployed Soviet SAMs have not been modified to provide them with a ballistic missile defense capability. It is technically feasible, however, for the Soviets to augment their ballistic missile defense by upgrading their SA–2 and SA–5 systems for such a purpose. The marginal effectiveness of additional ballistic missile defense which would result, along with the degradation [Page 727] in bomber defenses that almost certainly would result, make it a very unlikely Soviet course of action. It is agreed within the Intelligence Community that even in an arms control environment, in which Soviet opportunities to deploy ABM defenses would be limited, the shortcomings of upgrading SAMs for an ABM role would be recognized by the Soviets and would discourage them from following such a course.5

Defense Against Ballistic Missile Submarines

I. During the past three years the Soviets have deployed new surface ships, submarines, and aircraft with improved sensors and weapons which represent a concerted effort to deal with the problem of detecting, identifying, locating, and destroying nuclear-powered ballistic missile submarines in the open ocean. There is general agreement that the sonars on new surface ships and submarines represent an improved capability to detect and maintain contact on target submarines, although the degree of improvement remains debatable. (See alternative views in Section IV.)6 The Soviets are employing two new ASW Moskva-class helicopter ships, which operate as the leaders of a task force and greatly improve their capability for surface search for submarines. New nuclear-powered attack submarines have more powerful sonars, greater speeds, and operate more quietly. Two new ASW aircraft have much greater range and load carrying capability. The Soviets are also experimenting with fixed hydroacoustic arrays and with new types of moored and air-dropped buoys.

J. Despite these improvements, the Soviets are still a long way from developing an effective defense against ballistic missile submarines operating in the open ocean. For one thing, although two Moskva-type task forces may be able to place some constraints on Polaris operations in the Mediterranean, they do not constitute a significant threat to the survivability of Polaris submarines operating there. Because of the larger areas to be searched, the capability of these task forces against Polaris submarines in the relatively unrestricted waters of the Atlantic and Pacific Oceans, and the Norwegian and Barents Seas would be even more limited.7

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K. Lacking an open-ocean search capability, the Soviets might employ their new submarines to detect ballistic missile submarines at vulnerable points in their mission, while they are leaving port or passing through narrow straits, for example, and trail them to their open-ocean operating areas. Such trailing tactics might be either covert or overt. But present Soviet submarines still are unable to detect and trail covertly a Polaris submarine while it is on, or en route to, station. Their noise levels are still higher than Polaris. This not only degrades the performance of their sonars but also makes it virtually impossible for them to approach close enough to a Polaris submarine to trail it with passive sonar without being detected themselves. Elimination of the problem probably would require redesign of the submarines.

L. Overt detection and trail of patrolling or transiting Polaris submarines is a more likely possibility. The speed advantage and sonar performance of the new V-class submarine are such that they may have reduced the effectiveness of present US countermeasures in breaking trail. The theoretical Soviet capability of maintaining an overt trail does not now constitute a significant threat to the survivability of the Polaris deterrent, however, since there are not enough V-class submarines to conduct such trails on a sufficient number of Polaris submarines simultaneously, and since construction of the V-class is currently at a rate of only two a year. Moreover, the problem of initial detection remains.

Antisatellite Defense

M. The deployment of an extensive space tracking network and the development of an ABM system have provided the Soviets with an antisatellite capability as a by-product. We believe that a non-nuclear intercept capability has been demonstrated and could be used at any time against selected US satellites. The Moscow ABM system as located at Moscow and at the Sary Shagan test center has the accuracy and guidance to kill satellites with non-nuclear weapons at altitudes up to about 300 nautical miles (n.m.), at slant ranges of a few hundred n.m. The system could also be used in a ballistic intercept mode against satellites up to about 450 n.m. altitude, although this might require use of a nuclear warhead. The Soviets have also demonstrated a capability to perform orbital intercepts using maneuverable satellites. In tests, wherein the target and interceptor were launched so as to be in the same plane, the interceptor maneuvered in-plane to overtake and close on the target. A fully operational system would require greater flexibility than was displayed in these tests.


N. The Soviets have traditionally been preoccupied with defense and willing to expend the necessary resources for nation-wide defense in depth. The momentum of existing programs will continue for at least [Page 729] several years and keep the commitment to strategic defenses high. Moreover, the forces capable of mounting a nuclear attack on the USSR will continue to grow in extent and complexity, as the US brings in new systems, its NATO Allies continue to develop their nuclear armaments, and the nuclear capability of Communist China grows. The resources devoted to strategic defense will reflect such considerations as the status of technological development, bureaucratic competition for scarce resources, and general policy aims. Of these, technological development will probably have the most influence on future capabilities.

Technological Development

O. Since World War II, strategic offensive innovations have usually exceeded the capacity of defensive technology to counter them. The resulting defense lag is most acute in two areas: that of providing sensors—radars and sonars—to detect, identify, and keep track of targets, and that of providing the computers and associated equipment needed to process the information on which defensive systems operate. For without sensors and processing equipment to pinpoint the target accurately, the task of destroying it becomes very difficult, if not impossible. The principal defensive problems being encountered by the Soviets stem from the inability of current technology to provide sufficiently effective equipment at costs which permit widespread deployment.

P. Air Defense. The principal continuing problem in Soviet air defense is development of an effective capability to intercept low-altitude intruders. The major problem of low-altitude air defense lies in the fact that in most of the current radars, the echoes from attacking aircraft are lost in reflections from terrain features. An airborne radar system which can look down over land, as well as over water, and see targets against the background return from the terrain, would offer significant advantages over a vast proliferation of ground radars, however improved. The Soviets are undoubtedly working on the technology for an airborne warning and control system (AWACS) with an overland look-down radar, though apparently at a slower pace than estimated several years ago. As the required capabilities have not yet been demonstrated by the Soviets, its introduction before 1976 now seems unlikely.

Q. An interceptor that would work with the AWACS, utilizing a look-down air intercept radar and missiles with radar guidance that would enable them to engage aircraft penetrating at lower altitudes, is a Soviet requirement which will probably be met in the mid- or late-1970s. Such a system could be put on a further development of the new Mach 3 Foxbat interceptor just deployed, on a new interceptor specifically developed for this role or, more likely, on both.

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R. Another defense problem for the future will be that of intercepting ASMs now under development to be carried by US bombers. These nuclear-armed ASMs will not only present extremely difficult targets to Soviet air defenses, but they will also pose a saturation problem to Soviet air defense command and control systems. In order to intercept these ASMs with SAMs—there will be too many to attempt to do so with interceptor aircraft—the Soviets would have to upgrade considerably their current SAMs or deploy widely a new SAM system, or both. The modifications required to the SA–2 (if such were to be made) would include substantial changes in—or even replacement of—the radar, shortened reaction times, and faster interceptor missiles. These modifications, incidentally, might pose a serious intelligence problem because they might be confused with those for the upgrading of SAM systems for ABM use.

S. Antiballistic Missile. Soviet ABM development has been limited by the capabilities of radar systems to acquire a target, to tell whether the launch unit should shoot at it, and to do this in time if there is a large number of potential incoming targets. The development of new phased-array radars should provide significant increases in target handling capabilities for a follow-on ABM system in the mid-1970s or later. We believe that the Galosh missile of the Moscow system has sufficient propulsion flexibility for use in a loiter mode, i.e., a mode in which the interceptor is launched toward the general vicinity of the incoming objects, flies at reduced thrust until the target can be identified as it enters the atmosphere, and is then directed to the target at accelerated thrust. The loiter thus utilizes atmospheric sorting of RVs, but does not require a very high acceleration interceptor missile. There is still no firm indication of Soviet development of a high acceleration Sprint-type interceptor, or that launchers and radars are being hardened, as would be required; it is therefore unlikely that such an interceptor will become operational before 1975.

T. We believe a new defensive missile system is being developed in what may be a new complex at Sary Shagan. Galosh-type interceptor missiles are being tested at one launch site within the complex. The possibility of an air defense role cannot now be ruled out. The weight of our limited evidence indicates, however, that these components will probably have a significant ABM capability and that the system is probably intended to fulfill an ABM role. The Soviets may be developing a system utilizing a two-layer defense consisting of a modified Galosh in association with a new smaller missile and new radar. It might be used to increase the effectiveness of defenses around Moscow and may lend itself to rapid deployment.

U. Antisubmarine Warfare. The fundamental limitation of Soviet ASW remains the difficulty of detecting a submarine in the open ocean. We expect that Soviet sonars will continue to be improved during the [Page 731] 1970s, and that their submarines will be made more quiet. Even with the improvements projected for the end of the decade, however, a new submarine could not gain an advantage over Polaris sufficient to give any significant probability of maintaining covert trail for an extended period. The Soviet use of long-range acoustic detection systems is now limited by geographic and hydrogeographic conditions around the periphery of the USSR. Development of remotely emplaced acoustic detection systems may enable the Soviets to overcome this limitation in the next 10 years. To do this, however, would require significant improvements in their sensors and undersea cable technology. In any event, an open-ocean search or trailing capability, utilizing acoustic means of detection, and sufficient to neutralize the on-station force of Polaris submarines, appears beyond the reach of the Soviets during the 1970s.8

V. But we are not so confident in our judgments with regard to non-acoustic sensor developments. Non-acoustic methods seek to exploit thermal or electromagnetic radiation from the submarine, disturbances of the earth’s magnetic field caused by the submarine, or characteristic wakes created as it passes through the ocean. There is evidence that the Soviets are seriously investigating various techniques of non-acoustic detection. But we have almost no technical information about their programs. Indeed there is much uncertainty about technical feasibilities in this field, and little basis on which to estimate with confidence the contribution that non-acoustic systems might make to the solution of Soviet ASW problems in the coming decade. If significant Soviet progress should occur, the result might be a decidedly improved Soviet system for search of the open ocean. Though we might become aware that the Soviets were detecting US submarines with unexpected success, we might not be able at first to recognize the technical means by which they were doing so. In this sense, the development might come as a technological surprise.9 There would, of course, still remain the problem for the Soviets of incorporating these techniques [Page 732] into an effective counter to the US fleet ballistic missile force.

W. Antisatellite Defense. Efforts made thus far indicate the Soviets will have in the coming decade a tested non-nuclear antisatellite capability based upon their maneuverable satellite and ABM programs. As these two programs grow in sophistication and to the extent that additional ABMs are deployed, antisatellite capabilities will grow. A reliable capability for non-nuclear disabling of satellites up to and including synchronous altitudes (19,800 n.m.) can be expected in the late 1970s, and any widespread deployment of ABM defenses will increase the opportunities for attacking satellites in low-earth orbit. In addition, a laser system capable of producing physical damage to the film, the optical system, and other components of a satellite, could be available for use by the mid-1970s.

Strategic Alternatives

X. Developments in Soviet strategic defense forces over the next two or three years are reasonably clear, as they result from construction programs now discernible. Thereafter the alternatives open to the Soviets in the planning of their future strategic defenses become increasingly varied. A major indeterminate factor at present is the possibility of a strategic arms limitation agreement. If one is agreed upon, explicitly or tacitly, it may be limited to an agreement on ABM deployment, or it may be more comprehensive, including means for intercontinental attack as well. In these cases the Soviets might at a minimum accept mutual deterrence as a basis for strategic defense and do little more than complete current deployment programs. Without an agreement, they might continue to develop their forces at rates consistent with past trends, or they might attempt to achieve a maximum defense posture through greatly expanded deployment of improved and new air defense, ABM, and ASW systems. As between the various defensive forces concerned, they might continue to emphasize air defenses, while concentrating mainly on R&D programs in the ABM and ASW fields in a search for better solutions before deploying new systems. Or they could deploy ABM and ASW systems widely, with less emphasis on air defense. Within each of these general courses of action a large number of strategic force developments could take place.

Y. The various uncertainties summarized above make it evident that no exact estimate of the future Soviet force structure, at least after about the end of 1972, could be defended. We have therefore constructed in Section VII of this Estimate,10 several illustrative force models to depict selected possibilities. The first, called Force Model I, represents little more [Page 733] than a completion of programs presently under way; it seems unlikely the Soviets would stop at this. Another model, Force Model IV, is representative of what we believe would be a rough upper limit, short of converting to a wartime basis, especially if it were to accompany extensive deployment of intercontinental attack forces; this also appears unlikely.

Z. Between these models we have set forth two others which we consider to be more likely, but under differing conditions. Force Model II illustrates the level of effort and technical progress that might obtain if there were to be a comprehensive arms control agreement. Force Model III illustrates an approximate level of effort and of technical progress we think likely in the absence both of an arms control agreement and of a significant step-up in the arms race. But we wish to emphasize that all of these models are strictly illustrative, and not to be regarded as confident estimates or as projections for planning. As one moves beyond the next two years or so, all projections become increasingly uncertain; beyond five years they are highly speculative.

[Omitted here is the 80-page Discussion portion of the estimate.]

  1. Source: Central Intelligence Agency, NIC Files, Job 79–R01012A. Top Secret. The CIA and the intelligence organizations of the Department of State, the Department of Defense, the AEC, and the NSA 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 representative of the FBI, who abstained on the grounds that it was outside his jurisdiction. The table of contents, a glossary, and an annex with tables of the estimated characteristics and performance of weapon systems are not printed. The full text of this NIE, excluding the glossary and annex, is in the CIA FOIA Electronic Reading Room (www.foia.cia.gov).
  2. The forces costed under ASW are multi-missioned naval forces. For the purposes of this Estimate we have included the entire cost of these naval forces under ASW although the specific portion of their cost which is dedicated to countering the US fleet ballistic missile force cannot be distinguished from those costs incurred in acquiring their other mission capabilities. [Footnote in the original.]
  3. The dollar figures (appearing in parentheses after the rubles) are approximations of what it would cost to purchase and operate the estimated programs in the US. [Footnote in the original.]
  4. Vice Adm. Noel Gayler, the Director, National Security Agency, believes that with respect to command and control, the performance of the Moscow ABM system on its first full-scale test—when actually under ballistic missile attack—is almost certain to be well below design level. The cumulative effect of its various weaknesses suggests that the Moscow system has little capability to defend Moscow, except against a small and unsophisticated attack. [Footnote in the original.]
  5. On June 14, PFIAB sent President Nixon a “Report to the President on Soviet Strategic Defenses.” The report, which bears a stamp indicating that the President saw it, endorsed the findings of NIE 11–3–71 and noted the agreement in the intelligence community that the Soviets were unlikely to attempt to upgrade air defense missiles for an ABM role. (National Archives, Nixon Presidential Materials, NSC Files, Box 276, Agency Files, PFIAB, Vol. VI, Chronological File)
  6. Section IV deals with Defense Against Ballistic Missile Submarines.
  7. Maj. Gen. Rockly Triantafellu, the Assistant Chief of Staff, Intelligence, USAF, does not agree with judgments expressed in this paragraph. For his views, see his footnote to Section IV, page 50. [Footnote in the original.]
  8. Maj. Gen. Rockly Triantafellu, the Assistant Chief of Staff, Intelligence, USAF, does not agree with judgments expressed in this paragraph. For his views, see his footnote to Section IV, page 50. [Footnote in the original.]
  9. Mr. Leonard Weiss, for the Director of Intelligence and Research, Department of State; Vice Adm. Noel Gayler, the Director, National Security Agency; and Rear Adm. Frederick J. Harlfinger, II, the Assistant Chief of Naval Operations (Intelligence), Department of the Navy; believe US investigations of ASW applications of non-acoustic phenomena have been, and continue to be, sufficient to make the likelihood of technological surprise very small. Mr. Leonard Weiss further believes that the translation of such a development into an ASW weapon system capable of neutralizing the US missile-launching submarine force would still be a major undertaking extending over a period of several years, and doubts that such a capability would come as a surprise to the US. [Footnote in the original.]
  10. Section VII is entitled Future Forces for Strategic Defense.