device but also phased in the practice hydrogen and deuterium fillings as well as the necessary instrumentinstallation. This entire task required continuous coordination to ensure noninterference with either the experimental programs or the assembly program. This schedule was adhered to with only minor variations created by difficulties in obtaining tight vacuum systems either in the device itself or in the cryogenics system. The ACF personnel first After : ran into considerable difficulty in obtaining a this was remedied, the only problems encountered were those concerned with obtaining adequate vacuums in the cryogenics system. After the vacuum-system assembly was complete, the system wasfilled with hydrogen and eventually with deuterium. After each of these practice fills, the system was drained. The final filling operation was started the evening of M—6 days and proceeded according to schedule, except for difficulty in removing a solid air block in one of the deuterium lines. After the solid air block was removed,filling proceeded normally, and the system operated within designed limits. The device was detonated at 0715 on Mike Day. 4.5 TASK UNIT 5, KING ASSEMBLY TU 5 was assigned the task of preparing and delivering to the strike aircraft the King weapon and also the unit used for King The components for these units were procured through the Sandia Corporation Production Department. The King unit was shipped on the USS Curtiss, in its storage condition, to be assembled on the Curtiss in the Forward Area. The King unit was delayed until 20 October, which was the completion date on the parts for this unit. At this time it was assembled in a . ready condition, which means that it had detonators, fuses, and all components, : ready for firing. The King unit was stored in Albuquerque until M+3 days, when it was flown to Kwajalein on a C-124. These planes arrived at Kwajalein on 7 November. — The personnel of TU 5 departed from Albuquerque on 31 October and arrived at Kwajalein on 3 November. After their arrival, the USS Curtiss, which served as the TU 5 workshop, was brought alongside the dock,and the King unit was loaded aboard for storage. On 8 Novemberthe King’ unit was loaded into the strike aircraft, and all final electrical checks were made. This unit was expended on 9 November as scheduled. The King unit and all components were then checked in preparation for loading on 12 November. This weapon was flown tu the test area on 13 November, but, because of a solid overcast, the test could not be completed. After a 24-hr delay, it appeared that further delays would be encountered, and the King unit was unloaded from the aircraft and taken aboard the USS Curtiss again for check-out on 15 November. At 1400 on this sameday, the unit was reloaded into the strike aircraft with all final checks being made. This unit was expended at 1130 on 16 November. 4.6 TASK UNIT 6, FIRING PARTY The arming and firing of the Mike device were the responsibilities of the Firing Party, TU 6. This Task Unit was divided into an arming team and a firing team, which were functionally separate organizations with different missions. The arming team had the mission of arming the Mike device, which included making all final connections, tests, adjustments, and calibrations necessary to ensure a successful detonation. The mission of the firing team was to operate the firing control room aboard ship and to detonate the device at H-hour. The Firing Party set up specific operations as contained in the Firing Party Order and the Firing Party CheckList and, in addition, determined those procedures to be instituted in case of 58