cipation, The two most important decisions to evolve from this meeting were in connection with CASTLE Indirect Bomb Damage Assess- ment (IBDA) experiments and the determination of aircraft positioning in space at shock arrival times. It was decided that three B-50 aircraft of a squadron. located at Guam would be provided for IBDA participation, Three different aircraft and three different crews would be used for each participation. The other decision, which did not become final until later in December, concerned equipment to determine the aircraft position at shock arrivai times. After considering the K-17 visual camera; the O-15 radar scope camera; the MPQ-2, SHORAN (Short Range Navigational Aics): and the Raydist Navigational System; it was decided that Raydist would be the most accurate means but the cost involved in leasing them from the Hastings Corporation, the manufacturer, was prohibitive. When this was pointed out to the Hastings Corporation and the requirements redefined, a reasonable rental was agreed upon and Raydist was the equipment employed. _ During the latter part of November, CTG 7.4 and members of his headquarters staff made a command inspection at tne PPG to determine the state of readiness for receiving Task Group 7.4 in the forward arsa. Examination was made of the Eniwetok runway and runway shoul- ders; Building 135, which was to house part of the Task Group; and of the helicopter requirements at Bikini. Each of the above was a matter for discussion with General Clarkson in Hawaii when the inspection party returned from Eniwetok.