\ 15. In accordance with the Commission's desires as expressed at Meeting 1313 on November 6, the General Advisory Committee was briefed on the HARDTACK program, By letter to the Chairman, AEC, dated December 10, 1957, the Chairman of the GAC reported on the 56th meeting of the General Advisory Committee at Los Alamos, New Mexico, on November 21, 22 and 23. The following extract from that letter contains their comments on the HARDTACK program: "(1) PLUMBBOB and HARDTACK Series The Committee was presented with a thorough briefing of both the PLUMBBOB and HARDTACK Series by personnel from the Los Alamos and Livermore Laboratories. The Committee feels that both test series have been well planned, that they do not contain any significant duplication of effort, and that all planned tests in the HARDTACK Series should be carried out due to their importance. Also, the DOD shots are of importance and should be conducted in spite of the fact that they will contribute significantly to the release of fission products. However, due to the fact that they are to be tested at unusually high altitudes, fallout will probably not occur to an appreciable extent until the radioactivity has decreased, and then it will be at a low rate. The Committee does not feel that public reaction to the test series will be serious. The Committee has little to add to the briefings which have already been presented to the Commission, nor does the Committee feel itself qualified at this time to establish an order of priority of the HARDTACK Tests, Oohh piv . De Z } i i