80. Memorandum from Gen. Lemnitzer to President Kennedy, February 161

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  • Joint Chiefs of Staff Views on Resumption of Nuclear Testing (U)

1. The Joint Chiefs of Staff consider that there is an urgent military requirement for an accelerated program of nuclear tests in various environments, including the atmosphere. The security of the United States depends to a large extent upon our ability to assure superiority in nuclear weapons and our ability to employ them effectively. This requires that our weapons development programs be pursued aggressively without handicaps of self-imposed restrictions on the manner of testing new concepts.

2. The basic objective of the nuclear test program is to increase the military capability of US forces. In order to achieve this objective, full-scale nuclear testing in various environments is needed to permit:

a. Further development of advanced nuclear weapons.

b. Better understanding of the effects of nuclear weapons.

c. Proof testing of complete nuclear weapon systems in operational environments.

3. Although progress can be made in developing advanced nuclear weapons by underground tests supported by laboratory experimentation and theoretical analysis, only limited information can be obtained in the vital field of nuclear weapons effects. Then, too, there appears to be a finite yield limitation which cannot be exceeded in underground testing. Testing in the atmosphere offers the greatest opportunity for obtaining significant diagnostic and effects data for the devices and weapons fired. Additionally, complete weapons systems tests cannot be conducted in an underground environment.

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4. Our knowledge of certain weapon effects phenomena is extremely limited. The areas of principal uncertainty are the effects, particularly at high altitudes, which are pertinent to our missile defense, and to radio propagation and radar blackout; the effects in the oceans which are pertinent to fleet operations and antisubmarine warfare efforts; and the effects including both electromagnetic pulse and blast on hardened underground sites. The areas in which information is notably deficient include:

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a. Effects of the high intensity electromagnetic pulse generated by a nuclear detonation. We know this phenomenon exists. In the conduct of previous nuclear test series, certain detrimental effects of the EM pulse were noted but often not explained. For example, instrumentation cables were fused or melted at considerable distances from the detonation. Spurious signals were acquired, often destroying records and sometimes even equipment. We now have insufficient data to determine specific effects against our command-control, communications, and weapons systems. However, the possibility that vital elements of our defensive and offensive weapon systems may be paralyzed or destroyed by an enemy attack is a matter for investigation at the highest priority. One test is now planned to investigate this phenomenon in the spring of 1962. If we discover that our cabling for our command and control systems is highly vulnerable to specific yields from particular heights of burst, then we may be able to proceed toward a solution. Resulting actions could include: redesign and shielding of all important land lines systems; redesign and hardening of the communications and control systems of our missile launch sites; and the introduction of new, less vulnerable communication and control systems. Until we have adequate data, it is difficult to fully evaluate the extent of the impact upon our own capability. It is imperative that we not underestimate the potential effect that this knowledge by the enemy could have on our deterrent posture. The control and weapon systems supporting our nuclear deterrent posture may have serious technical flaws.

b. The phenomenon of electromagnetic blackout. Again, we know that this phenomenon exists. Certain of our tests at high altitude indicate that radio communications and certain radar equipment may be seriously degraded and in some cases rendered [Facsimile Page 3] ineffective for some hours after a detonation. We now have insufficient data to determine the extent to which this effect may be used against the United States to paralyze essential elements of our warning, command and control systems or to degrade our antiaircraft or antimissile systems. The limitations of our knowledge emphasize the high degree of risk which may be involved. Two tests are now planned to investigate this phenomenon in the spring of 1962. Resulting actions could include: changes in communication and radar frequencies; the multiplication of our radar sites and techniques. Again it is imperative that we not underestimate the potential effect that knowledge of these effects by the enemy could have on our deterrent posture. Conversely, our knowledge and use of these effects might so degrade enemy defenses that our own deterrent capability could be greatly enhanced.

c. The phenomenon of weapon system kill. There is reason to believe that the use of nuclear weapons will be the most effective means of countering the threat of enemy ICBM systems. Blast, thermal radiation, [Typeset Page 240] X-rays, and neutron flux may individually or collectively provide the mechanisms for the “kill” of enemy missiles. The degree to which any one of these effects may be of importance will depend upon the yield, detonation altitude, and CEP of the counterweapon and upon the degree of hardening of the enemy weapon. US knowledge of the magnitude and relative importance of these effects suffers badly from the paucity of experimental data. The evaluation of our defensive systems and the hardening of our own warheads and bombs against Soviet defenses are dependent upon such knowledge. Three of the tests planned for the US tests in the spring of 1962 will provide data on weapon kill effects and still other tests will be used as data sources if they are properly instrumented. It is known that the Soviets have a vigorous AICBM program and several of their recent tests can best be explained as efforts to enhance both their ICBM and AICBM capability. What measures we might take to prevent a degradation of our military posture will be dependent to a large degree on the information we obtained from our own planned tests. Some hardening against neutron heating is being incorporated in the warheads for POLARIS, ATLAS and TITAN. Also, a basic research program on warhead hardening has been proposed by the Defense Atomic Support Agency (DASA) to the Joint AEC-Department of Defense Warhead Vulnerability Board and action has been started to carry out this program.

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5. Development tests are important, since they will have a decided impact on the military capability of the nation. The purpose of nuclear weapons development is to provide this country with a stockpile of reliable, safe and efficient nuclear weapons, discriminating in effect and flexible in application consistent with military objectives. From development tests we could expect an increased yield-to-weight ratio that would basically permit delivery of higher yields for a given weight or allow for delivery to greater ranges of a given yield weapon by missiles and aircraft. Specifically, missile warheads of small weight will lead to smaller, more mobile, more serviceable missiles and will allow for better penetration through enemy defenses. New types of tactical weapons, including [text not declassified]. Frequently, in the past, new concepts or ideas of great value have developed from the effort to fulfill specific weapon needs. In this regard, the Joint Chiefs of Staff consider that the Atomic Energy Commission should be encouraged and permitted to explore new weapons technology at the maximum possible pace and be permitted to conduct the required nuclear testing with minimum restrictions as to the amount of testing.

6. The Joint Chiefs of Staff consider certain actions of the United States to be of paramount importance if the military confidence in our weapons, which comprise our current deterrent posture and operational capability, is to be maintained. Specifically, the primary weapons [Typeset Page 241] and weapon systems which comprise the major elements of the United States offensive and defensive military power should be mated and tested under operational conditions and in realistic environments. It is a matter of grave concern to the Joint Chiefs of Staff, the operational commanders of the Armed Forces, and to the organizations which support them, that plans involving national defense and survival should be dependent upon the validity of mathematical computations and indirect applications of components when positive proof is immediately available. A number of weapons have reached stockpile configuration only as a result of testing separate devices, component parts, shapes and laboratory experimentation, and, since entry into the stockpile, have been subjected to extensive modification and retro-fit. Many types of weapons now in the stockpile and included in war plans designed to accomplish US wartime objectives have never been completely tested in their war reserve configuration under those severe environmental conditions which will be experienced by the whole system, or delivered by the weapon systems designed to [Facsimile Page 5] deliver them. For example, the warhead for the POLARIS, one of our primary strategic missile systems in being today, has not been tested in its present war reserve configuration. [text not declassified] example of the technical problems that lessen our complete confidence in the new sophisticated weapons of our arsenal. Firing of complete operational missile systems could and should be integrated into over-all cold war planning so as to enhance not only our military posture in international negotiations but to increase our own level of confidence in the total reliability of our systems. Successful tests of two of our SIOP operational missile systems, ATLAS and POLARIS, would permit the United States to operate from a position of demonstrated strength and readiness.

7. In recommending the resumption of atmospheric testing, the question of fallout was considered. It has been stated that world-wide fallout resulting from atmospheric testing presents a real hazard to the population of the world. In contrast to these widely publicized opinions concerning the hazard, the Defense Atomic Support Agency has determined from extensive studies over the past few years that world-wide fallout from past nuclear tests has not produced a demonstrable biological hazard nor is it expected that any similar future tests would do so. By using the same careful procedures of analysis and prediction employed in previous tests in the atmosphere, control of local fallout can be accomplished without hazard.

8. The Joint Chiefs of Staff do not advocate the resumption of nuclear testing simply because of the recent Soviet tests. Nevertheless, the fact that the Soviets have completed these tests has accelerated the military requirement for resumption of testing. The full impact and military significance of the recent Soviet test series cannot be completely [Typeset Page 242] evaluated until the final technical assessment of all Soviet tests has been made. At the present time and for the near term, the strategic long-range nuclear delivery capabilities of the United States vis-à-vis that of the Soviets are clearly in favor of the United States. However, there is good evidence that the Soviets, in recognition of this imbalance in relative strengths, are striving for weapons systems that could in the future, provide them with a military advantage. It is apparent that the Soviets have achieved advances in nuclear weapon technology beyond that [Facsimile Page 6] which was commonly anticipated. Since no less than 45 tests were exploded by the Soviets during the recent series they have now at their disposal a mass of experimental data on weapons design and weapons effects which can be utilized during the next two or three years to greatly enhance the capabilities of their weapons systems. Preliminary information now available indicates that the 1961 nuclear test series has given the Soviets increased confidence in current weapons systems, advanced their weapon design significantly, added greatly to their understanding of thermonuclear weapon technology and contributed vital weapon effects knowledge. From the strategic viewpoint, Soviet progress in nuclear weapon technology will give the USSR increased confidence in their over-all military capability and their national power.

9. The Soviets can be expected to conduct further testing as required. They have already laid the political ground work for resumption of testing by their statements that US testing will force them to resume testing for national security reasons. Furthermore, their intransigence on the nuclear test moratorium issue indicates their unwillingness to limit their freedom of action in this respect unless a comparative strategic advantage in nuclear weapons can be obtained. The Joint Chiefs of Staff are confident that past Soviet behavior makes it patently clear that US self-restraint concerning atmospheric nuclear tests will not prevent the Soviets from further atmospheric testing.

10. In summary, the Joint Chiefs of Staff position for resumption of nuclear testing in all environments is based on the fact that the survival of the United States and its Allies may well depend on our ability to:

a. Obtain the critical effects data which could affect our:

(1) Radar warning systems.

(2) Radar guidance systems for our strategic missiles and aircraft.

(3) Communications with our National Command Posts and Retaliatory Control Systems.

(4) AICBM’s effectiveness.

(5) ICBM’s survivability for retaliation.

(6) Delivery of ASW nuclear weapons.

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b. Maintain the credibility of all of our nuclear deterrent forces ranging from our strategic ICBM systems and our air and submarine [Typeset Page 243] defense systems, down to the smallest battlefield tactical weapon. This credibility cannot be totally meaningful without each system having been completely proof tested and fired by operational crews.

c. Attain a strong posture with which we can increase our capability to execute the strategy of “controlled response”.

11. Our security and that of the Free World requires that we maintain a substantial nuclear superiority over the Soviet Union and the Communist Bloc. Early resumption of atmospheric testing, in the face of Soviet nuclear advances, will be required in order to maintain US nuclear superiority. In view of the above, the Joint Chiefs of Staff reaffirm their position on:

a. The necessity for resumption of full-scale nuclear tests as soon as practicable.

b. The military necessity for conduct of the presently proposed series of tests.

c. The necessity for not agreeing to any treaty which would limit the conduct of future US nuclear tests unless an effective inspection and control system is implemented and properly functioning.

d. The need for greatly augmented research in new weapons technology.

12. Appendix A contains a list of tests that the Joint Chiefs of Staff consider to be the most important from a military point of view.

13. In the event consideration is given to additional tests, Appendix B contains a list that the Joint Chiefs of Staff consider to have important military significance and would contribute to the over-all security of the nation.

For the Joint Chiefs of Staff:

L.L. Lemnitzer
Joint Chiefs of Staff
  1. JCS views on resumption of nuclear testing. Top Secret. 7 pp. Kennedy Library, National Security Files, Subjects Series, Nuclear Weapons Testing, 497th NSC Meeting.