Ix On 1 April 1958, the ten B-57B aircraft departed from Kirtland Air Force Base on the first leg of the trip to Eniwetok Proving Ground, At McClellan Air Force Base, the first stop enroute, the aircraft encountered a delay of some 12 days caused by adverse winds over the Pacific, but finally arrived at Eniwetok on 18 April 1958, aircraft arrived on 21 April 1958, sampling missions 2° ‘The three remaining B-57B They were readied immediately for The B-57D aircraft left Laughlin Air Force Base, accompanied by two C-12l support aircraft carrying maintenance personnel and equipment, on 6 April 1958. They also encountered adverse winds and arrived at Eniwetok on 1) April 1958, With few exceptions, the personnel and equipment for sampling were in place for operations by mid-April, As specified by Air Force, the Los Alamos Scientific Laboratory, and the University of California Radiation Laboratory, the number of samples ranged from one to ten, collected at various altitudes and depending upon 1 the nature of the shot. ? Shot and Aircraft Participation: Phase I Despite a proposed advancement of the starting date for HARDTACK, Phase I, the first shot, YUCCA, did not occur until 28 April. During Phase I, which eventually included a total of 33 individual shots, sampling aircraft flew 20 missions and logged 1,635 flying hours. “~Chart: Sampling HARDTACK, Phase I” Shot Date Type YUCCA 140 Balloon 28 April 1958 Remarks Drifted to 60 miles NE of Eniwetok “see Appendix II for number of samples taken on each shot. 182 eae SWEH~2-003k; On ns