Washing down and decontamination of the drones was accomplished by the air monitors, The washing was completed by the morning of X RAY-plus 3, Some slight fall-out was observed about 2100 of X-RAY Day. No activity was observed in any of the salt or well water intakes, By X-RAY-plus 3 the island and swimming beaches were cleared and by X-RAY-plus 5 the drones were cloared for flight to Kwajalein, Tank -LCM Operations ~— Radsafe Part: No. 6 The purpose of the Tank-LG! operation was to procure a soil sample from the crater at the point of detonation of the atomic weapon, A tank revetment was built on each of the test islands located as far as possible fran the sero point. In this revetment the chassis of a light tank, brilliantly minted for easy visibility, was concealed at the time of the tost. It was equipped with remote controls which permitted the vehicle to move either right, left, or forward, It was also fitted with a scoop in front for the purpose of lifting up a sample of the soil. When obtained this sample was divided into two parts, the smaller part was taken to the laboratory on board the USS BAIRCKO, and the other to Enuwetok where it was loaded on aircraft and flown to the Los Alamos laboratories in the United States, The tank was operated by remote control from a helicopter, after its operation had been checked by a yround operator, and it was guided by this nieans to the crater and return, If, for any reason, the helicopter and its standby lost control, the tank operation ceuld be taken over by an auxillary set of control equipment in the LOM which brought the party to the island. The LC! also carried an additional tank for use if the first tank failed, The nonitors assigned to this mission on X-Ray Day were LCDR Vandergrift and LT. Woy. Dr, Bowman, who was in charge of the mission, and Lr, Stanley, his assistant, remained behind on Enivetok completing the drone filter removal, as the Tank LOM took off for the test island. The IM picked up the monitors frem the BATROKO and beached at the lower end of the island not far fran the Tank Revetment. No damare had been done to the tank by the blast other than loss of the antenna. This was replaced, the tank was started and driven out of the revetment to await the arrival of Dr. Bowman and Ma, Stanley by helicopter. Upon his arrival at LUO, the tank controlling helicopter was called fram the BAIRCKO, and Dr. Bowman accompanied by LODR Vandersrift proceeded by jeep to lay out the flag markers, beyond which £¢ would bewnsafe for the tank controlling helicopter to fly, The tank performed well, and mide two runs with samples which were considered too low in intensity, On the third attempt the tank was stalled in the crater and could not be moved by rencte control. The reserve tank could not be used because it was now minus its radio antenna which it had sacrificed for the first tank. nn wo a”