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to another island. The islands were sprayed with 

 DDT to insure healthful conditions for Task Force 

 personnel. Towers to house cameras and television 

 apparatus were built. At Kwajalein the available 

 airfield installations were readied for the arrival 

 of the Air Group. Laboratories for chemical analy- 

 sis and photograph processing were constructed. 

 Little by little the ships of the target array as- 

 sembled and were brought to Bikini, most of them 

 through Pearl Harbor, which hummed with activity. 

 Installations of special equipment had to be made 

 on many vessels. Salvageable ship materiel was 

 removed. Army equipment scheduled to be se- 

 cured to the decks of the target ships and exposed 

 to the bomb's destructive force was placed 

 aboard. The German cruiser "Prinz Eugen" moved 

 from European waters to Philadelphia and on to 

 the Pacific. From Japan steamed the captured 

 Japanese battleship "Nagato" and the light cruiser 

 "Sakawa." Also to their rendezvous with destiny 

 came the valiant old battleship "Pennsylvania," 

 commissioned in 1916 and once flagship of the 

 United States Fleet, the 30-year-old veteran "Ne- 

 vada," first of the Navy's oil-burning super-dread- 

 naughts, the rugged carriers "Saratoga" and "In- 

 dependence." 



Several plans for the arrangement of the target 

 fleet were considered and revised. The directive 

 creating the Operation specified a disposition of 

 ships to give a graduation of damage from maxi- 

 mum to minimum. Major damage to ships close to 

 the explosion point, minor damage to ships at the 

 outskirts of the target circle, would provide valua- 

 ble means of analyzing the bomb's elusive fury. 

 The final disposition appears schematically at a 

 later place in this book. The concentration of ships, 

 from a Navy point of view, was obviously artificial. 

 More than 20 ships were compressed within 1000 

 yards of the bulls-eye ship. Ordinarily such an 

 area would be used to contain but a single capital 

 ship in a carrier force at sea, or three capital ships 

 in a normal anchorage. The principle of using an 

 arrangement that would provide graduated dam- 

 age, instead of one representing a tactical forma- 

 tion or anchorage, was followed in both tests. 



Instrumentation 



THE instrumentation program at Bikini consti- 

 tuted the heart of the Operation. More than 

 10,000 instruments were placed about on target 

 ships, in shore and observer ship and aircraft in- 



stallations. Simple and complex, the instruments 

 included many that were familiar long before Bi- 

 kini, many developed specifically for these tests. 

 Various staff divisions under the Technical Direc- 

 tor concentrated on apparatus. Their names hint 

 at the breadth of scientific observation planned: 

 bomb operation; pressure and shock; wave motion 

 and oceanography; electromagnetic propagation 

 and electronics; radiological safety; radiation; ra- 

 diometry; technical photography. 



The ships themselves were in a real sense instru- 

 ments, their recorded behaviour in the face of 

 the explosions revealing much of the nature and 

 development of the gigantic forces produced. In- 

 genious instruments on the ships measured roll 

 and pitch, recorded strain experienced by plates 

 and ribs, wrote down the temperature of ship 

 interiors, tested surrounding air for contaminating 

 radioactivity, radioed their findings to the ob- 

 server fleet miles outside the lagoon. Drone, or 

 unmanned, radio-controlled boats and planes 

 played an important part. The boats collected 

 samples of the radioactive lagoon water when it 

 was still too "hot" to handle. Drone planes pene- 

 trated where no man could have ventured, flew 

 through the mushroom cloud on photographic 

 missions, sampled its poisonous content, televised 

 to remote onlookers their instrument panel read- 

 ings for flight analysis. 



Cameras at Bikini took more than 50,000 stills 

 and 1,500,000 feet of movie film. One camera, 

 presumably the world's largest aerial camera, used 

 a 48-inch focal length telephoto lens capable of 

 taking a legible photograph of the dial of a wrist 

 watch a quarter of a mile away. One high-speed 

 movie camera operated at the rate of 1000 pic- 

 tures per second. 



Pre-test Training 



THE tests required special training of the 42,000 

 men who serviced the Operation. Procedures 

 were set up for placing the thousands of instru- 

 ments, for their care and activation, the collection 

 of their data. Underwater photography techniques 

 were developed as an aid in recording the data 

 from sunken ships. The drone plane and boat pro- 

 grams, Army and Navy, greatly advanced the art 

 of radiocontrol apparatus and its manipulation. 

 The fact.that Test Able was but the third atomic 

 bomb ever dropped from a bomber provided the 

 Army Air Forces with an incentive for considerable 



