~~ 2. WHY NUCLEAR WEAPONS AND DEVICES ARE FIELD TESTED In a world in which free people have no nuclear monopoly, the United States must keep its atomic strength at peak level. That is the primary reason why tests are held periodically in Nevada and in the Pacific. Most of the tests are intended to advance weapons development. Four areas of work are involved in the laboratory and field test development of atomic weapons: primary experimental research, theoretical investigations and calculations, component development experimentation, and full-scale nuclear detonations. If any one is neglected, the rate of weapons progress slows. The rate of testing required depends on the rapidity of generation of new ideas. At least nine developmental purposes are served by full scale nuclear tests: a. To proof test a weapon for desired military characteristics before it enters the national stockpile. b. To provide a firm basis for undertaking extensive engineering and fabrication effort which must be expanded to carry a "breadboard" model to a version satisfactory for stockpile purposes. c. To demonstrate the adequacy, inadequacy or limitations of current theoretical approaches. d. To explore phenomena which can vitally affect the efficiency and performance of weapons but which are not susceptible to prior theoretical analysis of sufficient certainty. e. To provide a basis of choice among existing theoretical _.methods of weapon improvement so as to concentrate effort along lines of greatest practical significance. f. To determine the validity of entirely new and untried principles proposed for applications to improve performance. g. To provide entirely new information pertinent and valuable to weapon development and arising simply as a by-product of scientific observation of full-scale detonations. h. To gain time in very urgent development programs by substituting tests for a portion of a possible but lengthy program of laboratory calculations and experiments. i. To provide as a by-product basic scientific information to add to the stockpile of such knowledge. -2- a: na 4