” PART II 9. THE 1957 NEVADA TEST SERIES July 15, 1957 The Purpose X \ In announcing plans for conducting a 1957 Test Series at the Nevada Test Site (January 25, 1957) the Atomic Energy Commission declared: "The program of tests is aimed to attain new knowledge important to the defense of the United States and the Free World, which must be maintained pending ultimate attainment of international agreement on safeguarded disarmament. The development of weapons for defense against attack is a major objective. Studies of weapons effects will also be continued in order to improve military and civil defense against nuclear attack," . Extent of Program More detonations have been scheduled for the 1957 series (known as Operation Plumbbob) than for any previous Nevada series, The exact number is not yet known and will depend on test results, It is possible that shots will be deleted or added because of the results of experiments previously conducted during the series. The following total of shots will have been held or announced by the date of this revision: seven tower shots to which newsmen are being admitted, plus two additional tower shots; two balloon suspension shots to which newsmen are being admitted, plus three already fired; an air-to-air rocket test; and an underground tunnel placement. These add up to 16, which is more than the total of 14 shots fired in the spring 1955 series, Each experimental shot ordinarily includes five or more key experiments and perhaps up to 75 or 80 experiments. The maximum number of experiments to be connected with the sequence timer in any one test in this series is 66. A shot is fired only if there is good assurance that key experiments will obtain the desired data, The designed yield of the Hood shot on July 5, 1957, exceeded the designed yield of the final detonation of the spring 1953 series, which was the largest in explosive force previously fired in Nevada. Like the final 1953 burst which was an air drop detonated well above ground level, the Hood shot, which was fired at 1500 feet suspended from a balloon, resulted only in very low level fallout in the region near the Nevada Test Site, Wil os COr i men, ~ 39 ~ d C\