58. Letter from Gilpatric to President Kennedy, October 91
Dear Mr. President:
In our letter to you of September 30, 1961, we outlined the basis for a proposed U.S. nuclear test program. In that report we informed you of the data which is needed and which can only be obtained through atmospheric testing. We now believe it is important that we [Typeset Page 167] further describe the experiments which are urgently required and recommend that you grant approval to prepare for a comprehensive test program. You will note that our greatest deficiency in effects data lies in those related to determining the vulnerabilities of our ICBM systems and sites, and those phenomena affecting the design of AICBM systems and hardening of warheads to secure penetration of enemy defenses.
Some of the less complicated tests can be conducted in a few weeks, while the more complex ones require up to two years for preparation. An extended period of time is required to complete the series because preparation was limited during the moratorium while the United States was negotiating in good faith. It is also important, in this context to make [text not declassified]. To accomplish this it is obvious that preparations must have been instituted about two years prior to resumption of testing. If we continue our unilateral restrictions or agree to a moratorium on atmospheric tests, we will have permitted the USSR to obtain a technological gain of several years and obtain information which will be denied us without atmospheric testing.
It is fallacious and dangerous to our national security to assume that we have reached a favorable plateau in nuclear weapons development, and that extensive efforts in nuclear testing are no longer required. On the contrary, from past experience we know that nuclear testing has enabled our scientists to make extraordinary progress, not only in weapon technology but in the discovery of previously unknown and unsuspected phenomena. We believe that similar gains can be made in the future.
[Facsimile Page 2]The current nuclear test series being conducted by the USSR is a clear demonstration of their determination to improve their military posture and must be considered as the culmination of a continuing vigorous and aggressive weapons development and systems test program. In contrast, during the voluntary test moratorium started at the end of October 1968, the United States, acting in good faith, conducted no nuclear tests of new weapons and no nuclear tests to study effects phenomena associated with nuclear detonations or to prove stockpiled weapons. The currently authorized tests, with yield and environmental limitations imposed by underground testing, do not permit the Atomic Energy Commission and the Department of Defense to pursue all aspects of a dynamic and effective test program.
The critical need for effects data vital to the national security lies in the weapons effects area that relate to ICBM and ICBM site vulnerabilities. The importance of these effects was not recognized early enough before the onset of the moratorium to instrument for their measurement in tests underway at that time. As a consequence, very little quantitative information is now available, and it is to correct this deficiency that atmospheric tests are urgently required. In addition, if [Typeset Page 168] such testing is authorized, weapons development could proceed at a much higher rate and we could accomplish several desirable weapons systems and stockpile weapons assurance tests. To meet these critical needs, programs should be conducted on a high priority and urgent basis to:
a. Obtain the necessary data relative to the vulnerabilities of ICBM systems and to assure that our AICBMs will be effective in a nuclear explosion environment. We urgently need the following weapons effects tests:
(1) [text not declassified]
[Facsimile Page 3][text not declassified]
Performance of [illegible in the original] weapons [illegible in the original] are presently in [illegible in the original] or are [illegible in the original] near future. While such tests [Facsimile Page 4] at full yield are not absolutely required, the tests indicated would give assurance as to the yields of the latest warheads and are tests that could be carried out at early dates. Specific tests are as follows:
| Warhead | Yield | Readiness Times |
| [text not declassified] | [text not declassified] | 3–4 weeks |
| [text not declassified] | [text not declassified] | 3–4 weeks |
| [text not declassified] | [text not declassified] | 3 months |
| [text not declassified] | [text not declassified] | 3 months |
| [text not declassified] | [text not declassified] | Spring 1962 |
| [text not declassified] | [text not declassified] | [text not declassified] |
c. Improve weapon technology with particular emphasis on increased yield-to-weight action, greater efficiency of base thermonuclear burn and the development of clean weapons. The present tests in Nevada are contributing to these objectives, but this program is subject to serious limitations. Specific initial development shots which would now be planned regarding overseas tests are as follows:
(1) [text not declassified]
(2) [text not declassified]
[Facsimile Page 5](3) [text not declassified]
The first of these tests could be ready in about six months with the remainder being completed in an additional six months. The operations could be conducted as airburst or barge surface shots with both options being desirable. However, all could be conducted as airburst, which in some cases would lead to loss of important diagnostic information.
d. Conduct operational test firings of Polaris, Atlas D and [illegible in the original] (Anti-Submarine Weapon System) systems. These full-scale firings would serve the vital purpose of providing realistic operational training. Psychologically, such firings could have a significant [Typeset Page 169] beneficial impact on the military posture of our forces as well as the forces of our allies. From a purely technical viewpoint, operational test firings to include full-scale detonations of the nuclear warhead have not been required in order to prove proper operations of those complete systems which are now in the inventory.
These full-scale operations can be accomplished with adequate safety and should be considered for inclusion in our program of test firings. Of immediate importance, the following demonstrations are recommended:
[Facsimile Page 6](1) [text not declassified]
Please note that the tests listed in (a) through (d) above are the most important and should not be construed as a complete listing.
Though a limited amount of valuable data can be secured from the current underground test series with low yield devices, it is being obtained at a relatively slow pace as is characteristic of underground testing. It must also be emphasized that testing underground can neither provide all of the effects data necessary to satisfy defense requirements outlined above nor permit the most rapid and full exploration of high yield weapon technology by the Atomic Energy Commission laboratories.
If it is desired to accelerate the present schedule of operations at the Nevada Test site (NOUGAT) significantly, it will be necessary to use balloon techniques. Under these circumstances the schedule could be modified as follows:
| Event | Purpose | Present Schedule | Balloon Schedule |
| [text not declassified] | [text not declassified] | Early November | Early October |
| [text not declassified] | [text not declassified] | Mid November | October |
| [text not declassified] | [text not declassified] | Mid-December | October–November |
| [text not declassified] | [text not declassified] | Mid February | October–November |
| [text not declassified] | [text not declassified] | Mid February | December |
Similar advances in schedule can be made for some of the less complex tests in the follow-on program.
We believe the best course open to the United States is to strengthen our military posture by conducting a comprehensive test program as indicated above. This will involve atmospheric tests to supplement the current underground test series. Intensifying our test activities is [Typeset Page 170] mandatory if we are to get the maximum technical data as quickly as possible. This will enable the United States to minimize the advantages being gained by the USSR in weapon and effects technology during their current tests. Once the United States resumes atmospheric testing, we must be prepared to stand firm in the face of any propaganda and conduct our test programs as necessary.
If you decide to permit the preparations for the tests outlined in this letter, it is important to recognize that in spite of taking every precaution against it there would be a risk that knowledge of the preparations would become public. In view of this fact and because the preparations would necessarily be on a large scale, it might be desirable to announce in advance that such efforts are underway.
Contrary to the widely publicised statements concerning the hazard associated with the fallout from atmospheric tests, the Defense Atomic Support Agency has conducted extensive studies over the past few years on the world-wide fallout of radioactive materials resulting from atmospheric testing. These studies indicate that, in actual fact, world-wide fallout from past nuclear tests has not produced a demonstrable biological hazard, nor is it [Facsimile Page 8] expected that any similar future tests would do so. The widespread belief that atmospheric testing is dangerous, arises in part from a misunderstanding of the basic differences between local fallout and world-wide fallout. It has been conclusively shown that the total radiation exposure to important areas of the body from world-wide fallout from all past tests is only 2 to 3% of the radiation exposure all individuals receive from natural sources. This increase is much smaller than the variations in dose that always have been imposed by nature on individuals living in different locales. We agree with the Defense Atomic Support Agency in this matter. As in the past, local fallout problems can be handled by appropriate safety precautions during the tests to insure freedom from danger.
In consideration of the above, we recommend that:
a. Approval be given for the Department of Defense and the Atomic Energy Commission to prepare for atmospheric and high altitude nuclear tests as outlined in this letter at suitable overseas locations, e.g., Christmas Island, Eniwetok, Johnston Island, open water and at the Nevada Test Site. Yield and operational limitations would be imposed as required to assure the health and safety of populated areas.
b. [text not declassified]
c. U.S. statements regarding the fallout hazard from atmospheric testing be based on known and proven facts rather than continued propaganda exploitation of the world’s exaggerated fear of radioactive fallout from tests in the atmosphere.
[Facsimile Page 9]d. Pending a decision to conduct the tests recommended, statements to the public should point out that the USSR nuclear weapons [Typeset Page 171] technology may well be overcoming our earlier lead, and the consequent national security need for a United States test program.
Sincerely,
- Seeks approval of a comprehensive test program. A proposed test schedule is attached to the letter. Secret. 11 pp. Washington National Records Center, RG 330, OSD Files: FRC 65 A 3464, Atomic 400.112, October 1961.↩