aspects of CASTLE would be known, a go-ahead for planning purposes was soon forthcoming. Modifications in the stated military sup- port requirements were to be made as late as February, 1953. One of the basic considerations in early CASTLE planning was the stringent one of insufficient land area for foreseeable future developments. With the advancement into the thermonuclear era, "real estate” at Eniwetok became a ccgent consideration. The com- plete elimination of Elugelab Island at the time of the MIKE detonation more than justified the earlier concern expressed on behalf ef this problem, As early as June, 1952, correspondence from Dr. Alvin ©. Graves, J-Division leader at Los Alamos and Scientific Deputy to the Task Forse Commander, pointed up tne necessity for exploring all possibilities of expanding the Pacific Proving Ground (PPG). As the matter was further studied, it also became more and more apparent that expansion for operational and logistical advan- tages would automatically follow any expansion which might occur for scientific and technical advantages. In August, studies by Dr. Graves and Holmes and Narver, Inc. (H&N), Los Angeles, concur- red on the choice of Bikini Atoll as the best site for an auxiliary proving ground. Bikini was close enough to Eniwetok (180 nau- tical miles to the east) to take advantage of the base facilities there and it did not require evacuation of natives since this had already been accomplished during Operation CROSSROADS in 1946. Cver and above the single matter of "real-estate", certain operational and logistical considerations necessarily were included