not tested during HARDTACK, he said, would be delayed entering the stockpile at least two years, Mr, Herbert York, Director, Livermore Laboratory, discuss with the Commissioners the weapons tests proposed by Livermore Laboratory. Mr. Libby noted that if the two high altitude she were eliminated from the test series, and no contingency shots detonated the off-site fallout from Operation HARDTACK would r exceed four megatons, the same as that resulting from Operatic REDWING. General Luedecke pointed out, however, that the Commission had originally requested these shots in order to determine whether detonations at 125,000 to 250,000 feet coulc be detected, This information is required before establishing a U.S. position on a possible world moratorium on weapons testing. More important to the DOD, he said, was the informat ta be learned about the effects of high altitudes on nuclear explosions, and the characteristics of radiation in varying densities of the upper atmosphere, needed, he said, The latter information Is in connection with research being conducted c method of attacking large numbers of enemy aircraft by the radiation from weapons dctonations. Mr, Libby observed that 3 the two high altitude shots and three contingency: shots were tested in addition to the other scheduled shots, the off~site fallout would total 8.22 megatons, The President, he said, wishes to limit, if possible, off-site fallout to the amount resulting from Operation REDUING, Mr. Libby added, however, t the President probably would agree to a total off-site fallout of not more than six megatons. Mr. Graham left the meeting briefly during the above discussion, General Luedecke said that if the two high altitude shots were removed from the test schedule, the DOD would wish to re-~ y 3- 7 a