and two water shots in the megaton yield ranze. A smaller array extend- ing to 15 miles was planned for the lower yield Echo shot.* 2e2 LAND AND LAGOON PHASE The land and lagoon phase of operations toox plece at Bikini Atoll for Shots 1, 2, 3, and 4 and at Eniwetok for Shot 6. sive preparations for Echo were made at Eniwetok, In addition exten- The instrumentation of the island and the lagoon raft stations is discussed in Chapter 3. The preshot preparetions at 8ikini involved readying the e,uipment, calibrating the instrmments, and emplacing them at the island ond lugoon raft stations, This was completed a week prior to Shot 1. Final checks were made on the equipment at all the existing stetions 1 to 2 days before shot time to assure ccmplete readiness and operational efficiency. rreparations were also made for the r-covery operations and for the re-instrumentation of the stations. Participation in all detonations except Shot 5 was achieved although not to the extent originally planned. The lesser participation was due to the destruction of equipment by the fire in the compound at Tare fci-~ lowing Shot 1, Tables G.1 through G.20, Appendix G, snow the degree of instrumentation and recovery for each shot, 2.3 PHASE Free~floating buoys were selected for sampling fallout in the open ocean on the basis of their evalwtion at IVY// tach buoy station was so located that it was expected to drift to the desired positicn by shot time. Records were kept of the locations and times of placement and recovery of each buoy. From these data, positions at shot time were r estimated by assuming that each buoy drifted in a straight line at a constant speed, It was essential that the time the buoys were et sea be held to a minimum so that their locetion at shot time could ve estimted as accurately as possible, For this reason the array for each test was laid out within 36 hr of the proposed shot time snd recovered as soon as possible afterwards, Sea phase operaticns were mounted from Eniwetok Atoll for all shots. Detailed direction, once Naval wits vere committed, was accomolished from ships based at Bikini Atoll or from vessels actively participating in Project 2.5a operations, 2.3.1 Pretest Freparetions The buoys and asscelated equipment were assembled and tested at Parry Island. Liaison was estublished with the Navel Tack Group and plans for conducting the sea phase were made. These plans consisted of loeding two sea-going tugs with csuipment at Eniwetok Atoll, after which the vecsels proceeded to sea to lay the buoys. After completion of the buoy lcying operctions, the tugs retired to a safe area to await the shot. Upon receipt of clearance from the Naval Task Group Commander folloving the shot, the tugs proceeded to recover buoys after which they returned to inivetok to off-load, Detailed plans for laying the buoys, * Not fired, 28 ey