&@dKT . SECTIOX , .. 11 PRE.TEST TRAINING AND OPERATIONS The dual character of the mission assigned to Joint Task Force Seven demanded the execution of two parallel, but distinctly separate, lines of endeavor. While the construction of the proving ground was being carried on to completion by the construction elements of the Task Force, the operating elements, Air; Naval, and Radiological units and staff sections such as the Meteorological and Communications units were engaged in the pre-test training and operations necessary to the accomplishment of the second part of the mission; participation in the conduct of the tests of atomic weapons. This pre-test period of training and operations, while it extended backward in some respects to the time before the Task Force left the United States, covered essentially the period from mid-March when the Task Force arrived at Eniwetok and Kwajalein until Peter-Xray Day, 8 April 1948. Peter-Xray Day was the culmination of this pre-test period: a full dress rehearsal of the operation as it was to be conducted on test days, Xray, Yoke and Zebra Days. Prior to sailing from Terminal Island at the end of February, the major ships of the Task Force were especially fitted out there at the Navy Yard for the mission. Laboratories for technical personnel and special communications were installed. Approximately 6,500 Naval personnel (TG 7.3) were checked for security purposes. Earlier, in November, an advance group of ghips consisting of the Comstock (Landing Ship Dock), four LST’S and two freight ships had arrived to support the construction operation and to establish and maintain a small boat pool for lagoon travel. During February offshore patrol, both air and surface, was established at Eniwetok Atoll. This patrol consisted of Destroyers and Destroyer Escorts and aircraft of VP (MS) -6 type with the USS Gardiners Bay acting as seaplane tender. Due to submarine contacts made within the danger area, the surface patrol was augmented almost immediately, to make a total of five surface craft, DD,’DE. In March it was decided that the situation was such as to require further augmentation of the patrol and the strength was increased to a total of eight Destroyer and Destroyer Escort. Daylight aerial searches were flown by VP (MS) -6 aircraft, using one plane daily for six days a week and a fiveplane search one day a week.21 During this early part of the operation the advance Naval unit continued to support the construction force as it built up. The unit surveyed small boat channels and installed channel buoys at the islands of the atoll which were important to the operation. Small craft landings were constructed and navigational aids were checked, improved and relocated where necessary, and correct hydrographic information was provided. Meanwhile, the Air Forces of the Task Group were in training and were conducting tests at Eglin Air Force Base, Florida, to lay the ground work for later tests at Eniwetok for the purpose of determining the minimum light conditions as related to dawn, in which the drones could operate efficiently. Drone aircraft were being readied at this time for use in collecting radiological samples from the radioactive cloud. Twenty-four B-17 aircraft ~’Special report o! T.G, 7.3,Sec. VII,