3. In a letter of June 13, 1952, circulated previously as AEC 493/4, the Military Liaison Committee transmitted a Joint Chiefs of Staff requirement for the development of thermonuclear weapons which follows in part: "a, A military requirement exists for the develop- ment of thermonuclear weapons giving yields of one megaton upward; a military requirement exists for the production of such weapons provided they are compatible in size, shape and weight with delivery systems that will be available .in 1954, "e, The Joint Chiefs of Staff wish to emphasize that prior production of a deliverable thermonuclear weapon by the USSR would serve to reduce the present U.S. preponderance in atomic weapons, and that such a shift in balance might exert strong influence on Soviet policy decisions, This factor, when taken together with the promise of U.S. thermonuclear programs, is considered to provide adequate justification for an approach which may represent considerable tech- nical risk and large expenditure of funds." 4, Because of the urgency of the thermonuclear weapon development as expressed in the above paragraph the reorientation of the thermonuclear program must obviously be related to such policy considerations as well as to technical considerations. Since the production of a proven weapon involves full-scale test~ ing, the date to be set for the CASTLE operation will be an in- portant determinant of the scope and emphasis of the development program and the time at which operational capability will be realized. this date. There is need for the earliest possible decision on This paper discusses the. main issues pertinent to timing of Operation CASTLE on the basis that the finally approved programs of LASL and UCRL will include projects indicated in letters from Drs. Bradbury and York circulated in AEC 597/2, and recommends a date for the test program which should satisfy the technical requirements as well as the DOD requirements. ~e@-

Select target paragraph3