began with two temporary camps in operation: at Yvonne a camp was established in support of the Cactus event, and at Janet a camp was established and operated in support of the Koa event. The permanent base camp for scientific operations was established at Parry. Personnel having primary interest in the early Eniwetok events, particularly Cactus and Koa, lived at the temporary campsites. All recovery and re-entry operations were controlled from the base camp at Parry.““The normal re-entry — recovery operation was as follows: 1. Requirements for re-entry — recovery operations were submitted by project personnel on special cards designed specifically for this purpose. 2. After cards were edited, they were published as an annex to the evacuation and re-entry letter which served as the Task Group operation order for the event. 3. After publishing the evacuation and re-entry letter, changes were posted to a master copy in the J-3 Office. On —2 day all project personnel who had established requirements for the event were queried to reaffirm the requirement. This procedure was repeated on —1 day to firm up the shot day requirements and thereafter as often ag —1 days occurred. 4. Initially it was decided that the rad-safe survey would commence at H+3 hr with a survey of the critical recovery areas to be followed by a more detailed survey at H+5 br to specifically delineate the Radex areas. However, it was determined after the first two events that a survey time of H~l hr was more realistic and provided a much better working period for the early recovery operations. With the exception of Cactus and Koa, two surface bursts, radiation levels were seldom of an intensity to prevent early recovery of critical scientific data. Critical recoveries were normally com- pleted on shot days, although the radiation levels did force a delay or postponement at times. A predawn detonation favors recovery operations, and, all other factors being equal, should be sought as the optimum condition. 5. Following the radiological survey of the contaminated areas, recovery teams were immediately dispatched to their respective stations to effect recovery if the radiation dose was suitable for the individual and the stay time involved. Several unique recovery operations were undertaken during Operation Hardtack. These included the recovery of floating coracles, film packs, and activated Pinex samples. Another recovery method effectively employed on Hardtack was to effect early recovery of fallout by grappling containers from their location on the funnels of the YC's by helicopter. On Umbrella, radchem analysis was started on some samples at H+40 min. ASP rockets were used to evaluate their effectiveness as cloud sampling vehicles. Despite the extensive efforts put forth in air-sea combined operations to effect their recovery, only a small percentage were located and retrieved. It was later determined that the rockets were not acting properly upon entry into the water and were sinking before recovery operations were organized. The most valuable experience gained from the rocket recovery was the requirement to have an organized sea-air team with common communications and centralized control. The main camps at Elmer and Fred were not evacuated for any of the shots, although extensive shoring operations were performed on weaker structures prior to shot Oak. Helicopters and light aircraft were evacuated from Elmer to Fred on those events where overpressures were expected to be in the neighborhood of 0.3 psi. For shot Oak, helicopters and light aircraft 98