12. Memorandum From Kistiakowsky to Killian1

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  • Technical progress and actions required in the Long Range Ballistic Missile Program


  • G. B. Kistiakowsky, Chairman, Ballistic Missiles Panel

I. The technical progress in long-range ballistic missiles has been faster than anticipated in 1953–54 when the large-scale effort began. This progress can be summarized as follows:

there is now a high degree of confidence that both the liquid and the solid propellant engines of large thrust will perform satisfactorily, although neither type will have 100% reliability in the early phases of operational use;
the airframes light enough for long-range missiles have been shown to have satisfactory structural strength and aerodynamic properties;
self-contained, “all-inertial”, guidance has already exceeded initial expectations and CEP due to guidance alone at 5500 mile range of less than 1 mile is within sight;
the re-entry of the nose-cone into the atmosphere without burning up appears to be near solution, not only for the 1500 but also for the 5500 mile range missiles;
thermonuclear warheads of megaton yields and acceptably small weight, which were predicted but doubted four years ago, are now a reality.

II. This rapid technological progress gives assurance that every major ballistic missile program can result in a prototype operational missile system within originally planned time scale or very shortly thereafter. The initial uncertainty of success led to a number of back-up programs: [Facsimile Page 2] Thor and Jupiter for the IRBM; and Atlas and Titan for the ICBM. Now that there is high confidence that each one of these programs will produce an operational missile within specified time requirements, the justification for continuation of all four missiles should be examined.

Thor and Jupiter are technically and performance-wise very similar, but they are sufficiently dissimilar to require two different ground support efforts, different training staff and manuals, and spare parts pipelines for each of these missiles. There seems to be very little [Typeset Page 32] justification to producing two similar missiles with the same performance. Thor has had more advanced testing and is closer to production than Jupiter. We recommend that it alone should be chosen for continued development and use, while Jupiter should be terminated as soon as practicable. This decision will result in considerable dollar savings, will reduce the burden on the Air Force of making two weapon systems with different GSE, training procedures and spare parts operational at the same time and will make ABMA available for other projects.

In the case of Atlas and Titan the situation is different because Atlas is much nearer being operational but Titan promises to have better initial performance and has greater improvement potential. The need for an early operational ICBM makes the termination of Atlas impractical, but this project should not be encouraged to engage in development work beyond that needed for IOC, because Titan can become operational some 18 months later if adequate funding is provided.

III. The Fleet Ballistic Missile, Polaris, with a solid propellant engine, is in an early stage of development. The introduction of solid propellant engines into long-range ballistic missiles has many important advantages: the engines are comparatively simple and are instantly ready to fire; the reliability, judging by the performance of smaller rockets, is very high. The performance characteristics required of solid propellant engines for use in ballistic missiles are, however, far higher than achieved in the past. Furthermore, solid propellant engines add greatly to the difficulties of all-inertial guidance. It is believed that in time these problems will be solved and since the solid propellant ballistic missiles are very advantageous from the operational point of view, their vigorous development is strongly recommended.

The first version of Polaris, A–1, a missile of about 1000 miles range, is scheduled to be operational in 1960. This schedule appears to be realistic, but there may be navigational and guidance difficulties in conjunction with its use as a FBM which will not be entirely solved in the early stages of operational availability of Polaris.

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Polaris B, a missile of 1500 mile range, is planned to become operational in 1963. The advance from Polaris A–1 to B involves some rather dramatic improvements in the solid propellant engines and we are not at all sure that the actual progress will be as rapid as planned. It should also be emphasized that the reliability of the early operational Polaris may not be all that is being anticipated for it by its enthusiasts because of several novel features never before used in solid propellant engines.

At about the same time that Polaris will become a fleet ballistic missile it should be possible to have a land based version of this missile, provided the Air Force is satisfied with its performance. If the Air Force desires to change the specifications then there might be an additional delay of one or two years in obtaining a solid propellant land-based IRBM.

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IV. The earliest availability of a land-based 1500 mile missile with a solid propellant engine is thus 1963, but it will probably be delayed until 1964–65, notwithstanding a maximum effort. To develop a solid propellant ICBM is a still more difficult undertaking and its earliest availability is 1965, while 1966–67 is a more realistic date, unless a crash program is initiated. There is thus a gap of some five years or more between an early IOC of present IRBM and ICBM and the start of their possible replacement by solid propellant missiles. This gap justifies the consideration of a systematic “product improvement” program on one present IRBM (Thor) and one ICBM (Titan) to accompany the steady growth of operational capability of both. We should like to emphasize that the value of liquid propellant engines and of missiles using them need not end with the present models. It appears that the present types of airframes and engines can be comparatively readily modified to use storable, self-igniting (“hypergolic”), propellants, which will give them the advantages of solid propellant engines—simplicity and thus greater reliability, rapid reaction time, easier transportability, reduced ground support equipment and operational personnel. For a rather long time to come liquid propellant engines will carry heavier payloads for longer distances than will solid propellant engines of the same total weight.

While these considerations justify a steady improvement program for the Thor IRBM, they are truly compelling in the case of ICBM Titan. This is a missile with a great growth potential as an ICBM of unlimited range and very large payload. If anti-missile-missiles [Facsimile Page 4] become effective the large payload of Titan may become a necessity, to carry along sophisticated devices to overcome the defenses. Solid propellant ICBM of similar payload capacity are presently not within sight. A retaliatory ICBM force made up of Titans with sophisticated nose cones and of solid propellant ICBM’s with much lighter (and therefore not so sophisticated) nose cones, may prove to have an exceptional effectiveness.

V. We as a nation seem to commit ourselves to a substantial effort toward space exploration. In any such program the propulsion is an essential and the major part. For economy’s sake we should use for this purpose rockets developed as ballistic missiles. Titan even in its presently conceived form is a better booster for space missions than is Atlas. A systematic improvement program on it will provide a satisfactory booster for rather advanced space missions. For still more advanced missions, such as manned flights to the moon and beyond, far larger and more advanced engines will be required than are now in the state of development. To avoid being caught in a crash program, it is advantageous to initiate preliminary work on such engines in the near future.

  1. Source: Progress and recommendations in ballistic missile program. Secret. 4 pp. Eisenhower Library, White House Office Files, Additional Records of the Office of the Special Assistant for Science and Technology.