The original concept for the Bikini Atoll was of a 500-man "shot island" camp with an airstrip suitable for use by C-47 aircraft and test facilities adequate for detonation of one device. This relatively simple concept evolved into a complex operation involving temporary campfacilities on four different islands of the atoll, with a total capacity of approximately 1900 people, facilities for interatoll and intra-atoll air and water transportation, extensive radio and telephone communication systems, and scientific structures, control station and timing and firing circuitry adequate for detonation of six test units all in the greater than one mmegaton range. Aside from the construction and operation of base facilities to accommodate the operational Task Force at the various locations, the major effort of TG 7.5 was directed toward construction of the numerous scientific stations and their many inter-related facilities. Extensive changes in plans of the Scientific Task Group as to devices to be tested, location of tests, and whether or not they were to be centered on barge or ashore introduced delays in planning and executing the scientific construction program. Late receipt of structural criteria on numerous structures complicated an already strenuous schedule for design, procurement of materials and equipment, shipment to the Jobsite, and construction. In September 1953, an evaluation of con- struction progress and scientific program development resulted in a de- cision to defer the date of the first detonation of the series from approximately 15 February to about 1 March 1954. There was no postponement or delay of any test in the series due to nonavailability on schedule of struc- tures or support services. A large majority of the minor scientific stations were completed and occupied by the Using Agency in advance of construction schedules. Beneficial occupancy of major scientific stations by the Users was obtained by the desired date. Since the receipt of design criteria was the starting point from which TG 7.5 construction activities began, it can be appreciated that a schedule for the receipt of this information was of paramount importance, and the Manager, SFO, set a deadline of 1 May 1953 for the submission of criteria. This deadline was ten months prior to the first test event, and the majority of the criteria was received by the deadline date. However, muchof this information was only sufficient to establish a requirement and lacked the detail necessary for the preparation of preliminary working drawings. In many cases the supplemental details were not forthcoming for 30 to 60 days; in other cases, where criteria had been hastily assembled, changes were still being received several months later. It should be appreciated, however, that the 1 May deadline occurred during Operation UPSHOT/KNOTHOLE, the results of which affected much of the scientific planning for CASTLE. To allow additional time for the submission of final criteria and still meet construction schedules, certain time-saving arrangements were made such as the use of air freight in lieu of land and water freight, bills of materials were prepared from preliminary drawings, and procurement was ac-~ complished without competitive bidding. While such expediting saved valuable time, a number of undesirable effects resulted, which included: higher 33