1151 i ut ori A th Ah W1 1 Cll5 05__ _J in Fep y refer to Initials 9 andNo 1 NAVY DEPARTMENT 99 878 1 OFFICE OF THE CHIEF OF NAVAL OPERATIONS 25EPMORHNDUM FOR Jenn curses cs 3mm Subject Tests of the Effect of Atomic Explosives l The threat of atomic explosives is producing radical thinking about future warfare which will influence the size and nature of the Army end'Nevy The changes which this threat may re quire and the dengess which may result from loose thinking on the subject can be so far reaching that I consider the early determina- ition of salient facts to be a matter of prime importance 2 I believe a number of tests will be required one or b_ more to determine effects on ships of current design and at least one to determine the effectiveness of design changes resulting therefrom Ships underway are or readily can be spaced sufficiently far apart to make them unprofitable targets for atomic bombs of the present order of cost However improvements in stability in resistance to heat radiation blast and underwater shock appear to be in order and their need should be evaluated The threat to ships in port is a different matter and will probably require radical changes in the number -size and layout of fleet bases and anchorages It may also require radical changes in the design of ships 3 The supply of atomic bombs is so small and their cost so great that the numbers expended for all purposes must certainly be held to the essential minimum For the Nave the primary facts which must be determined are the effects of atomic bombs exploded either in the air or under water on hulls material and personnel The results of the trials already made and the drops on Hiroshima and Nagasaki should be utilized to the fullest extent possible to predict in advance the results of pro posed trials Each future test should then be carefully designed on the basis of these predictions to yield the greatest amount of new informaw tion It may be that the effect of sir bursts can be determined in the main from the results of trials already made 4 It would be highly profitable to use surplus ships which are nou'availsble as targets for the first two tests A number of uncompleted combatants of various types are at favorable states of construction for economical incorporation of design changes resulting from the first two tests and are being held so for that purpose ve-95 111 11 i Authoriwa sb m a fn eply refer to Initials I 0115105 NAVY DEPARTMENT 378 1 OFFICE OF THE CHIEF OF NAVAL OPERATIONS m WASHINGTON 25 D Sm 0b gun 3 4 ff gum Subject Tests f the Effect 9 WAtomic Explosises 5 It would-appear to be both possible and profitable to select a target site such that all services and other interested agencies of the government can make the determinations they consider essential in a single series of tests One of the Caroline Islands might be well suited 6 Public interest in atomic eXplosives is so great that any disclosure of plans to conduct the proposed tests or of the fact that they have been conducted would be likely to produce great pressure for early release of details which might reduce or even cancel the value of the information gained Accordingly I recommend that the project be kept in very high security classification 7 I recemmend that the Joint Chiefs of Staff initiate studies of this project with a VieW'to making early recommendations to the President jig i Admiral Leahy General Marshall Admiral King General Arnold General Handy rAdmiral Edwards rank KDObe e wle MAI