Operation Crossroads

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Well-known photo of the Baker test. The Wilson cloud caused by the pressure wave has partially dissolved and reveals the water column and the cauliflower-shaped explosion mushroom as well as the fleet of target ships. The palm trees on the beach had been painted black and white to measure the height of the expected tidal wave.

The Operation Crossroads was the second nuclear weapons test operation of the United States Armed Forces . It comprised the two nuclear tests Able and Baker on Bikini Atoll , captured by the United States during the Pacific War , each with a TNT equivalent of 23 kT: Test Able was one dropped from a Boeing B-29 on July 1, 1946 and in 158 meters above the lagoon ignited Mk.3- plutonium - implosion bomb , identical to the Fat Man that was dropped over Nagasaki. Test Baker on July 25, 1946 was an underwater detonation of a bomb of identical construction in 27 meters of water. A third planned test, Charlie , was due to take place at an even greater depth on March 1, 1947, but was canceled.

Operation Crossroads involved a total of over 42,000 soldiers, mainly members of the United States Navy , and civilian scientists; in addition, 149 escort ships and a total of 100  target ships as well as 156  aircraft . The two nuclear weapons tests were the first to take place in front of the world’s eyes. Over a hundred reporters were present, as were military and scientific observers from around the world, including the Soviet Union .

The aim of the tests was to research the effects of nuclear weapon explosions on ships and their operational capability, but also on other military equipment such as vehicles and aircraft as well as military equipment that was exposed to the tests on the ships. A large number of test animals were also exposed to the effects of the explosions in order to study the direct, but also long-term effects of radiation exposure. 15 target ships were sunk by the explosions (five at Test Able , ten at Baker ), some of the others were very badly damaged. More than 90% of the target ships were severely radioactively contaminated , especially through the Baker test, the accompanying scientists gained extensive knowledge about immediately occurring, locally strongly concentrated radioactive fallout . The indigenous people of Bikini Atoll, 167  Micronesians were, prior to the tests on the previously uninhabited atoll Rongerik resettled where they were completely dependent on external supply. Due to the strong radioactive contamination of the atoll and the lagoon, the drinking water and the local flora and fauna, a return of the indigenous people to the Bikini Atoll is still impossible.

The chemist Glenn T. Seaborg , longtime chairman of the Atomic Energy Commission , called the Baker test "the first nuclear disaster".

prehistory

Planning

In 1944, during the Second World War , the scientists in Los Alamos were considering destroying the Japanese fleet at its main bases by means of targeted nuclear weapons; after the almost complete destruction of the Japanese fleet in the sea ​​and air battle in the Gulf of Leyte , these considerations were initially postponed. Just a few weeks after the successful Trinity test and shortly after the atomic bombs were dropped on Hiroshima and Nagasaki , Senator Brien McMahon from Connecticut, in a speech on August 25, 1945, proposed exposing the remaining Japanese ships to a nuclear weapon in order to make this weapon more effective to investigate ships and fleets. He took up a suggestion that Lewis Strauss had made in a letter to the Secretary of State for the Navy, James V. Forrestal .

Lieutenant General Barney M. Giles , a member of General McArthur's staff in Tokyo , recommended the destruction of the Japanese fleet by a nuclear test on September 14, 1945, citing Senator McMahon's speech. He was assisted in this by Major General Curtis E. LeMay .

On September 19, General Henry H. Arnold of the United States Army Air Forces asked the US Navy whether ten of the 38 captured Japanese ships could be made available for weapons tests. The Navy responded positively to this request, as the US Navy was also planning to investigate the effects of nuclear weapon explosions on ships as part of the Underwater Explosion Program of the Bureau of Ships and the Bureau of Ordnance. The US Navy presented its plans on October 16, and Fleet Admiral Ernest J. King explained in a press conference plans for a nuclear weapons test, which should include 80 to 100 target ships and which should be carried out jointly by the Air Force and Navy under the command of the United Chiefs of Staff . These target ships should also include modern ships of the US Navy, which were available with the end of the Second World War and the associated reduction in the size of the fleet. At the end of August 1945, the Secretary of the Navy proposed reducing the US Navy from its war strength of 1,200 ships to 400 ships and 8,000 aircraft.

Dispute over responsibilities

William HP Blandy, Commander of Joint Task Force 1

On October 31, 1945, General Arnold hired the Joint Staff Planners, a planning committee of the United Chiefs of Staff, to develop more detailed plans for the nuclear test. On November 13th, this planning staff appointed a sub-committee consisting of General Curtis LeMay, General WA Borden, Colonel CH Bonesteel, Captain GW Anderson, Jr., Captain VL Pottle and Commodore WS Patterson. This subcommittee, which dealt with important questions about the upcoming test for the next six weeks, was referred to as the "LeMay Subcommittee". His most important tasks were answering the question of whether the ships should carry a full load of ammunition and fuel during the test, and clarifying the high command about the joint task force to be set up. After ongoing disputes over whether the US Army, which had already worked on the Manhattan Project, or the US Navy, which would provide most of the material and personnel in the test, should be given high command, the Joint Chiefs of Staff appointed Vice Admirals William HP Blandy on January 11, 1946 as Commandant of Joint Task Force One. The US Army candidate, General Leslie R. Groves , was unable to prevail. Previously, on December 28, 1945, the Joint Chiefs of Staff had accepted the plan for the test procedure drawn up by the LeMay Subcommittee, which was also signed by President Harry S. Truman on January 10, 1946 .

Under pressure from the Army, Admiral Blandy was ready to position more ships than originally planned in the center of the target area; However, he rejected General LeMay's request for the target ships to be fully ammunitioned and refueled, as subsequent explosions and fires could result in more ships being sunk, making it difficult to evaluate the damage caused by the nuclear weapon explosion. Blandy's proposal to have the results of the test evaluated by a US Navy commission met with strong opposition from Senator McMahon and the Army; For this reason, President Truman set up a commission of civil scientists to evaluate the test results, also to convince the public that the evaluation was carried out objectively.

Leslie Groves was very critical of the nuclear test and its public implementation very critical to negative. He feared a loosening and violation of the previously very strict secrecy and worked only very reluctantly with Joint Task Force One.

Resistance to the nuclear test

Resistance to the planned test arose primarily from the diplomatic corps and various scientists. Some scientists from the Manhattan Project, who advocated a public test as a demonstration instead of a deployment before the atomic bombs were dropped on Hiroshima and Nagasaki, have now argued that further testing was unnecessary and posed a threat to the environment . A study by the Los Alamos National Laboratory warned that near a surface explosion, the water would be "a cauldron of radioactivity." When Admiral Blandy, in response to the objection of some scientists that the effects of the nuclear explosion on seafarers could not be researched, ordered the use of laboratory animals on board the target ships, he received heavy criticism from animal rights activists and animal rights activists . Letters of complaint were received from animal welfare organizations and private individuals from all over the United States, and the US embassy in London, for example, was inundated with letters of protest abroad.

US Secretary of State James F. Byrnes , who a year earlier had advocated a nuclear test to physicist Leó Szilárd in order to be able to impress the Soviet Union in Europe, now rejected the test because he feared that another American nuclear test would take place in the Soviet Union could reinforce their negative position towards the Acheson-Lilienthal Plan . At a cabinet meeting on March 22, 1946, Byrnes said that, in his opinion, it would be best for international relations if the test were postponed or not taken at all. Byrnes was able to prevail at Truman, who postponed the test by six weeks, from May 15th to July 1st. In relation to the public, the reason for the postponement was that more MPs could attend the tests when there were no sessions.

Criticism has also come from some congressmen, particularly Senator Scott W. Lucas , and veterans 'associations for fear of wasting taxpayers' money. The target ships used in Operation Crossroads had cost around 450 million US dollars (adjusted for inflation: 5.5 billion, as of 2016) to be built; Admiral Blandy countered that 90% of the ships were no longer operational and would only be ready for scrap; the scrap value of the target fleet was about 3.7 million US dollars. In addition, questions arose as to whether it would not make more sense to use the ships e.g. B. to be converted as living ships for veterans or, in the case of battleships, to be preserved as museum ships .

To appease his critics, Admiral Blandy delivered a speech on February 21 that was repeated several times over the following three months:

“The bomb will not start a chain reaction in the water converting it all to gas and letting all the ships on all the oceans drop down to the bottom. It will not blow out the bottom of the sea and let all the water run down the hole. It will not destroy gravity. I am not an atomic playboy, as one of my critics labeled me, exploding these bombs to satisfy my personal whim. "

“The bomb will not start a chain reaction in the water that will turn everything into gas and cause ships in all oceans to fall to the sea floor. It will not blast a hole in the ocean floor through which all the water will drain. It won't destroy gravity. I'm not an atomic playboy, as one of my critics called me, who lets these bombs explode on a personal whim. "

Radio Moscow on March 20 accused the United States of "wielding the atom bomb for purposes that have little in common with world peace and security". The Pravda asked a week before the test, "Why must demonstrate a blind trust in the intentions of the United States, while the United States obviously distrust not only their partners but also the international control all other states?"

Objectives of the test

The main aim of the nuclear test was to research the effect of atomic bombs on warships "in order to obtain valuable information for national defense." The target ships were arranged in the center of the test area at a density three to five times higher (about 7.7 ships per square kilometer) than would occur during a real fleet deployment. The aim of this arrangement was not to reproduce a real, anchored fleet, but rather it should provide as many measured values ​​as possible in order to show the damage to the ships as a function of the distance from the center of the explosion.

Another important aim of the test was to clarify the extent to which it would be possible to salvage ships that had survived a nuclear explosion and make them operational again. The most important aspect here was the monitoring and containment of radioactivity on board the ships.

Weapons, aircraft, tanks, wheeled vehicles, spare parts and military equipment, fabrics, clothing, food, medical material as well as operating and lubricants, but also electrical and electronic devices were positioned on board the target ships to protect them from the nuclear weapon explosion and its radiation and pressure effects suspend. Their suitability and survivability in a possible nuclear dispute should be checked.

Ships involved

Parts of the target fleet in Pearl Harbor on February 27, 1946

The Joint Task Force One consisted of two large parts - the target fleet, which was exposed to the effects of nuclear weapons, and the support fleet, which ensured the logistics and monitored the test.

The target fleet comprised 93 ships. These included four decommissioned American battleships , two aircraft carriers , two cruisers , eleven destroyers , eight submarines , various transport and landing ships as well as two former Japanese ships, the battleship Nagato and the cruiser Sakawa , and a former German ship, the Prinz Eugen . With years of construction between 1912 and 1944, the ships represented 32 years in the development of warships. The flagship of the target fleet, but not the target itself, was the heavy cruiser USS Fall River . Rear Admiral TA Solberg, Director of Ship Material, had the task of making the target ships absolutely watertight in preparation for the test. Warships, especially if they have been riveted and not welded, are never 100% watertight, but the penetrating water is removed by bilge pumps in everyday operations . However, since the target ships sometimes lay at anchor for weeks without a crew and with their pumps switched off, the Japanese ships in particular were feared that they would sink prematurely. Great emphasis was also placed on maintaining internal watertightness, as prematurely flooded watertight compartments could distort the assessment of survivability in the event of a nuclear attack. Army equipment and vehicles were positioned on the deck of the target ships to expose them to the effects of the explosions.

The support fleet of Operation Crossroads consisted of 149 ships of various types, which were divided into five task groups with different tasks. The flagship of the fleet and the entire operation was the USS Mount McKinley . In addition to the two aircraft carriers USS Shangri-La and USS Saidor, the support fleet included 15 destroyers as well as various transport, salvage, rescue and landing ships. The flagship Mount McKinley and the Appalachian , which was to serve as a "floating press center ", were equipped with the latest radio and television transmission technology for use . The seaplane tenders USS Cumberland Sound and USS Albemarle have been converted into floating laboratories for the assembly and maintenance of nuclear weapons. This made them the only mobile storage and maintenance facilities for nuclear weapons in 1946.

Preparations in Bikini Atoll

Map of the Bikini Atoll

The Bikini Atoll was chosen for the tests of Operation Crossroads because it met most of the demands made by the US armed forces: it offered a large enough lagoon to anchor the ships there, it was almost uninhabited, it was far enough away from shipping routes and other inhabited islands, its climate was without great extremes, the water currents were predictable, and it was under American control. Only the requirement for constant winds from sea level up to 18,000 meters was not met, as on Bikini Atoll, as on most tropical islands, the winds at low altitudes mostly come from the east, but in the stratosphere from the west blow.

Construction of the instrument towers

On January 24, 1946, Admiral Blandy declared that the first two tests should take place in the interior of the lagoon in the summer of 1946, the third planned test should then take place west of the atoll in deep water in the spring of 1947. Since the first test was originally supposed to take place on May 15, 1946, preparations began on the atoll immediately after the announcement. The survey ship USS Sumner arrived in Bikini on February 6 and began to blast a fairway through the reef surrounding the lagoon. In total, over 100 tons of TNT were used to widen the fairway and remove coral beds in the lagoon. Five remaining Japanese sea mines were also cleared by mine clearance boats in March after the majority of the mines had already been removed in September and October 1945.

The USS Bowditch began accurately surveying and mapping the atoll and lagoon, as the Japanese maps previously available were too imprecise. Scientists called upon by the U.S. Geological Survey , the Fish and Wildlife Service , the Smithsonian Institution, and the Woods Hole Oceanographic Institution , among others, also studied the flora and fauna of the islands and the lagoon. Over 20,000 fish were caught and studied, including a number of previously unknown species.

1000 soldiers of the 53rd Naval Construction Battalion , whose first units arrived at Bikini on March 11th, began erecting the required buildings on the islands on March 20th. In addition to twelve 25 meter high steel lattice towers that were supposed to carry cameras and scientific instruments, numerous other small wooden towers and various huts made of wood and steel were built to accommodate measuring instruments. Seven pontoon bridges were built to connect the islands of the atoll. Various workshops were built, a seawater desalination plant and a seaplane ramp , but also casinos for officers and scientists as well as a clay target shooting range , a sports field and several basketball , baseball and volleyball fields .

To combat insects on the islands, the two main islands of Bikini and Enyu were sprayed several times and the smaller islands of Aomoen and Eniirikku once extensively with dichlorodiphenyltrichloroethane (DDT).

Resettlement of the population

Arrival of the indigenous population of Bikini Atoll on Rongerik, March 7, 1946

After the Bikini Atoll was selected as the test site, the Military Governor of the Marshall Islands, Commodore Ben H. Wyatt, ordered the relocation of the entire indigenous population of the atoll. He traveled personally by seaplane from Kwajalein to the atoll on February 10, 1946 in order to persuade the inhabitants to voluntarily, temporarily relocate. In his address he compared the bikinians with the " children of Israel whom the Lord saved from their enemies and led to the promised land ". The chief, who called himself King Judah, spoke up and said that they were ready to go and that their fate was in God's hands. Nine of the eleven heads of families ("alaps") spoke out in favor of the uninhabited atoll Rongerik about 200 kilometers east of the Bikini Atoll as a new home. On February 25, a tank landing ship arrived in Bikini Atoll , carrying an advance team of 22 Bikinians and 15 Seabees to Rongerik, where an entire village was built the following day. A month's supplies and drinking water were also brought to Rongerik. After the February 10 meeting was repeated in front of the Navy film cameras, the 161 residents of the atoll were brought to their new homes on March 7, 1946 by the armored landing ship USS LST-1108 . The Bikini Atoll church was dismantled and rebuilt on Rongerik, and the outrigger canoes of the residents were brought to the new island on board the tank landing ship. The entire resettlement campaign was completed on March 10th.

Scientific instruments

Operation Crossroads nuclear weapons tests were monitored by a large number of measuring devices and recorded by a large number of film and photo cameras . The main focus of the measurements was on the pressure exerted on the ships of the target fleet by the explosion. Directly related to the pressure, the momentum of the detonation wave on the ships was measured, as well as the speed of propagation of the shock wave. Further measurements provided information about the emitted optical radiation , in particular ultraviolet and infrared radiation as well as ionizing radiation .

Over 5000 pressure gauges were used for the tests , the simplest of which were simple empty canisters that were deformed by the pressure wave. The difficulties of the pressure measurements lay on the one hand in the extremely high pressures that occurred, and on the other in the very short pressure peaks caused by the shock wave. The measuring devices therefore had to respond quickly and still have a large measuring range. For this reason, most measuring devices worked with deformations, from which the pressure was mathematically derived, or with a series of bursting discs that yielded at a defined bursting pressure . The pressure gauges were positioned everywhere in the target fleet, the ones with the largest measuring range in the middle, near the planned zero point of the explosion. Particular emphasis was placed on avoiding pressure wave reflections that would have falsified the measured values.

Numerous inclinometers were installed on board the ships to record the roll and yaw movements caused by the pressure wave and thus document the effects.

The measurement of the optical radiation was carried out by bolometers and thermocouples as well as spectrometers . A quick response was important with these measuring devices, as strong fluctuations in the spectrum and intensity of the emitted light would take place in a very short time. High-speed cameras should also record the spread of the fireball in the first fractions of a second. Human observers were given heavily tinted glasses to protect their eyes from the intense radiation. These glasses only let through about 0.003 percent of the visible light and were found to be way too dark during the test.

Cameramen on board a C-54 aircraft

In total, over 700 cameras were used to capture Operation Crossroads on film. Over 500 photographers and cameramen were hired by the military and around half of the world's supply of photographic film was brought to Bikini Atoll, which led to a shortage of photo materials on the world market. The photographic equipment of the United States Army Air Forces alone comprised a total of 328 cameras, including high-speed cameras with recording speeds of up to 10,000 frames per second and a photo camera with a telephoto lens with a focal length of 1200 mm - at the time the most powerful telephoto lens in the world. These cameras were also installed in B-29 bombers and C-54 freighters to photograph the explosions from the air.

The plans were for a million photos to be taken in the first few seconds after the bomb was detonated during the Test Able. The Army Air Force alone wanted to capture 9 million images of the entire test. In addition, the Army Air Force was planning to shoot around 360 minutes of film in the first four seconds after the ignition. Extensive precautions have been taken to protect cameras and films from the immense radiation, both non-ionizing and ionizing, as well as the pressure waves. For this purpose, for example, the cameras positioned on land were located in lead-lined housings with automatically closing doors. To develop the films, a huge photo laboratory was built on the Kwajalein Atoll in order to be able to develop the large number of images and films promptly.

F6F air sampling drones; the different colors of the tail units indicate the different control frequencies.

The radioactivity and ionizing radiation were also intensively measured, tracked and logged for health and safety reasons. The radiation protection group around Colonel Stafford L. Warren brought over 20,000 radiation measuring devices to Bikini, most of them so-called film dosimeters , which were issued to the personnel working in the immediate danger area, but were also installed on the target ships. There were also numerous portable and stationary Geiger counters for radiation monitoring during and after the tests. To drones converted B-17 bomber , launched from Kwajalein and others from aboard B-17 bombers were remotely controlled, and Grumman F6F-drones who from aboard the aircraft carrier Shangri-La were remote controlled, should air samples at different heights of the mushroom explosion.

Laboratory animals

Goats on deck of the USS Niagara before the test

In June 1946, 200 pigs , 200 mice , 60 guinea pigs , 204 goats and 5,000 rats were on board the converted transport ship USS Burleson , which for this purpose was equipped with pens , feed troughs and a non-slip concrete deck coating and carried 80 tons of feed for the animals , brought to Bikini. The 5664 test animals were positioned on a total of 22 ships in the target fleet, taking the stations where the crew would also be in the event of a battle. In order to obtain precise data on the effects of a nuclear weapon explosion on the crew of a ship, some goats were rubbed with sunscreen, while others had their hair cut to study the effects of radiation on their skin. The pigs, whose skin is very similar to human skin, were provided with radiation protection suits and treated with radiation protection creams. The scientists attached particular importance to the fact that the test animals survived the test, since "dead animals would have less value for studies".

"We want radiation-sick animals, but not radiation-dead animals."

"We want radiation-sick animals, but not radiation-dead animals."

The scientists assumed that once the radiation sickness had subsided, the animals could be returned to the United States, where they would continue to be available for study until they died naturally.

Test procedure

Test Able

On June 30, the crew members left the target ships and, together with the support fleet, the lagoon. Navy Minister Forrestal, who had traveled from Washington, received a final briefing on board the fleet flagship before the support fleet took up its position 15 nautical miles east and northeast of the atoll that evening. On the surrounding islands and atolls, evacuation ships and airplanes stood ready in case the wind would blow the fallout unfavorably.

The planning for the test sequence was for the bomber to take off at 5:34 a.m. local time. However, the flagship Mount McKinley was not released until 5:40 a.m. , as Admiral Blandy wanted to wait for the weather to improve . The Boeing B-29 Superfortress , named " Dave's Dream " by its crew around Major Woodrow P. Swancutt in honor of a crashed squadron comrade, did not leave Kwajalein Atoll until 5:55 am. In addition to the pilot Major Swancutt, 13 other crew members and Brigadier General Roger M. Ramey , commander of Task Group 1.5, were on board the bomber .

Able test mushroom a few seconds after the explosion
The mushroom explosion has spread to a greater height

At 8:03 a.m., the bomber arrived over Bikini Atoll and began the first of several training approaches. After a first overflight over the target fleet, during which the wind speed and direction as well as the radio link were checked, a full simulation of the target approach including the simulated drop of the bomb followed at 8:20 a.m. 30 minutes later, the final approach to the target began from a distance of almost 100 kilometers. At an altitude of 28,000 feet , approximately 8,500 meters, the Mk.3 atomic bomb was released at 8:59:46 a.m. Immediately after being dropped, the B-29 began to descend in a sharp left turn in order to increase the distance to the bomb. The explosive device was “christened” after the film “ Gilda ” and “decorated” with a photo of its leading actress, the sex idol Rita Hayworth .

48 seconds later, at 9:00:34 a.m. Bikini time, the bomb exploded with an explosive force of 23,000 tons of TNT equivalent at a height of 158 meters above the target fleet. Within a few seconds, the mushroom explosion rose to over 6,000 meters, its top height was around 16,000 meters. The pressure wave, which initially spreads at over 4,800 meters per second, caused severe damage on board the target fleet, but was only heard as a distant thunder on board the escort fleet 90 seconds after the explosion. The fireball, which had a surface temperature of well over 100,000 ° C in the first few seconds, spread at great speed before it had given off its radiant energy. A large part of the emitted optical radiation was weakened and absorbed by the humid atmosphere.

Effects of Able

Map of the target fleet of the "Able" test with the explosion center. About half of the target ships were outside this section. The five Xs mark the positions of the sunken ships, the circle with a radius of 914 meters shows the area of ​​the most severe damage. The planned target point of the bomb was the battleship Nevada , # 32 (marked in red here), but the bomb landed near ship # 5, the troop carrier Gilliam . All of the submarines in the target fleet were on the surface. The Nagato (# 7), which was only 130 m from the Nevada , was only slightly damaged.
Sunk ships
# Surname Type distance
5 Gilliam Troop transport 45 m
9 Sakawa cruiser 384 m
4th Carlisle Troop transport 393 m
1 Anderson destroyer 457 m
6th Lamson destroyer 694 m
Heavy damage
# Surname Type distance
40 Skate Submarine 365 m
12th YO-160 Yard Oiler 475 m
28 Independence Aircraft carrier 512 m
22nd Crittenden Troop transport 544 m
32 Nevada Battleship 562 m
3 Arkansas Battleship 566 m
35 Pensacola cruiser 649 m
11 ARDC-13 Floating dock 754 m
23 Dawson Troop transport 781 m
38 Salt Lake City cruiser 818 m
27 Hughes destroyer 841 m
37 Rhind destroyer 925 m
49 LST-52 Tank landing ship 1399 m
10 Saratoga Aircraft carrier 2071 m
The target ship USS Nevada was painted orange as a target marker for the bomber crew
The heavily damaged and burning light aircraft carrier USS Independence after the Able test

The bomb missed its intended target, the battleship Nevada , by 649 meters and exploded only about 50 meters from the troop transport ship USS Gilliam , which capsized and sank within a few seconds as a result of the pressure wave. Another troop transport, the Carlisle , which had been moved more than 50 meters from its position by the shock wave, sank on fire after 40 minutes. The Anderson , a destroyer, sank within four minutes, another, the Lamson , sank after a few hours. The Lamson was farther from the zero point of the explosion than some other ships, but unlike other ships, she had turned the full broadside of the pressure wave and had been badly damaged. The Japanese cruiser Sakawa burned violently and sank the next morning. The superstructure of the Nevada , actually the target of the bomb, was relatively lightly damaged. Smaller fires on board partially extinguished by themselves. The light aircraft carrier Independence also suffered severe damage , large parts of the flight deck and hangar deck were destroyed, and several fires broke out Board off.

The target fleet was photographed several times from the air, remote-controlled boats took water samples to determine the radioactive contamination. Remote-controlled B-17 bombers flew into the mushroom a few minutes after the explosion to take air samples. When the OK from the flagship came at 2:30 p.m., the ships of the support fleet returned to the lagoon, where the scientists began to evaluate the results. The big deviation of the bomb from the planned target turned out to be a big problem. Most of the cameras, especially the high-speed cameras, had been aimed at the Nevada and hadn't recorded the explosion. Many measuring devices were exposed to values ​​that either exceeded the measuring range or were below the sensitivity. With the Gilliam , a large number of measuring instruments for measuring the speed of shock waves had also sunk to the sea floor or destroyed. From the point of view of many scientists, the data that could be recovered from the target ships were of no use, the operation as a scientific experiment was devalued.

Like the two nuclear explosions in Hiroshima and Nagasaki, the Able test was an air explosion high enough that hardly any material was sucked from the ground into the rising fungus. The fission products of the explosion were carried by the mushroom cloud into the stratosphere, where they were distributed globally, the locally falling radioactive fallout was rather low. The explosion was described as "self-cleaning". However, ships near the zero point of the explosion were heavily irradiated by neutron radiation . 10 percent of the animals used were killed directly by the pressure wave, another 15 percent by the radiation from the fireball. Several surviving animals developed symptoms of radiation sickness as a result of the test, whereas burns and eye damage were rather rare.

Missing its actual target, the Nevada , created tension between the Army Air Force and Los Alamos Laboratories, which blamed each other for the false drop. Los Alamos claimed the Air Force made incorrect calculations about the flight path. Even Paul Tibbets , who was defeated by Swancutt and its crew in the selection process for Operation Crossroads, argued that the calculations of the trajectory and the discharge point were wrong. The Army Air Force, however, blamed Los Alamos Laboratories and their design of the bomb or their poor aerodynamic design for missing the target. Even an investigative commission set up by the high command, which questioned all crew members of the "Dave's Dream", analyzed film recordings of the drop and also had test drops carried out with dummies in New Mexico , could not find an exact cause for the failure despite months of investigation.

Preparations for the Baker test

LSM-60 in the Bikini-Lagune, the winch frame and the radio mast can be easily recognized

In preparation for the second test of Operation Crossroads, the target ships were rearranged. Damage has been fixed and leaks have been sealed so as not to distort the results. The bomb, which had been named "Helen of Bikini" by the soldiers involved in the test, was to be detonated in a watertight container under the landing ship USS LSM-60 . LSM-60 had been converted for this purpose prior to testing at Terminal Island Navy Yard in California . An opening was cut into the bottom of the hull on the loading deck, and a winch frame was placed above it , with which the bomb could be lowered to its intended depth. In addition, the ship was equipped with a radio mast in order to be able to receive the radio signals for detonating the bomb. Since the functionality of the landing craft and its technical facilities were very important for carrying out the test, spare parts for all the equipment were carried on board. In the immediate vicinity of the LSM-60 , which formed the center of the target fleet, were the Saratoga and the battleship Arkansas , which was anchored only 200 meters from the planned zero point, about 400 meters away .

A test run was carried out on July 19 to rule out errors in the test. In the early morning of July 25, all ships in the escort fleet left the lagoon to position themselves about 15 nautical miles away.

Test Baker

4 milliseconds after ignition: the gas bubble created by the fireball breaks through the surface of the water and throws a column of water into the air

The detonation of the atomic bomb, which was 27 meters below the surface of the water and thus halfway down to the bottom of the lagoon, took place on the morning of July 25 at 8:34:59 a.m. local time by a radio signal from the USS Cumberland Sound . As in the first test, the bomb developed an explosive force of 23,000 tons of TNT equivalent.

The Baker test generated so many previously unknown phenomena that a conference was held two months later to name it. The fireball and gas bubble created by evaporating water reached the surface of the lagoon within milliseconds, while the shock wave of the explosion spread at a speed of 5600 kilometers per hour, clearly visible in the water as a dark, spreading ring that resembled an oil spill . This ring was followed by a white, steadily growing disc that was created by the churning up of the surface of the water. The hydraulic shock wave caused the greatest damage on board the target ships, reaching pressures of over 680 bar . LSM-60 , which was directly above the bomb, was completely destroyed by the blast from the explosion.

Aerial view: The Wilson cloud obscures large parts of the water column; the disk caused by the pressure wave can be seen on the surface of the water

When the gas bubble of the fireball broke through the surface of the water, a clearly recognizable water dome was formed, which burst like a geyser after a few milliseconds. A massive column of water, radioactive material and debris from the lagoon floor shot up. The water column of 2 million tons of water, which was almost 600 meters in diameter and had about 100 meters "thick" walls, was almost empty inside. After a few seconds, a cauliflower-shaped head formed, which continued to enlarge. Most of the "cauliflower" was made of material from the bottom of the lagoon, where the explosion left a crater 610 meters wide and 9 meters deep. The column and the target fleet were temporarily covered by a hemispherical " Wilson cloud ", which was caused by the pressure wave propagating in the air.

The fully formed cauliflower shaped explosion cloud (the central water column begins to fall back into the lagoon)

After about ten seconds the water column began to collapse. A huge, radioactively contaminated spray cloud (“ base surge ”) enveloped the entire target fleet when the water plunged back into the lagoon from a height of almost 2000 meters. This spray cloud, at the beginning just 100 meters high, reached a maximum height of about 600 meters and spread at about 40 kilometers per hour. The radioactive mist of the spray cloud settled on every surface of the target ships and, even after drying, left strong radioactive contamination that made it impossible to enter the ships in some cases.

When the water flowed back into the cavity created by the gas bubble, several tsunami- like waves were created that were around 25 to 30 meters high near the center of the explosion. The waves hit the islands as a group of around 15 waves with breakers up to five meters high, where they caused floods. The returning water carried around 50,000 tons of sand from the islands' beaches.

Effects of Baker

Map of the target fleet of the "Baker" test with the explosion center. Half of the target fleet was outside of this map section. The ten red Xs mark the positions of the ten ships that have sunk as a result of the test (see table). The black circle with a radius of 914 meters shows the area of ​​the most severe damage. The blue circle, radius 300 meters, shows the dimensions of the underwater crater as well as the water column that has completely enclosed Arkansas . The submarines were submerged, Pilotfish (# 8) to a depth of 17 meters above Kiel, Apogon (# 2) to a depth of 30 meters above Kiel. Other ships in the immediate vicinity of the bomb: # 31 USS New York , # 32 USS Fallon , # 38 USS Salt Lake City
Sunk ships
# Surname Type distance
50 LSM-60 Landing ship 0 m
3 Arkansas Battleship 155 m
8th Pilotfish Submarine 331 m
10 Saratoga Aircraft carrier 411 m
12th YO-160 Oil lighter 475 m
7th Nagato Battleship 704 m
41 Skipjack Submarine 731 m
2 Apogon Submarine 777 m
11 ARDC-13 Floating dock 1051 m
The USS Saratoga sinks due to severe damage from the Baker Test.

The hull of the battleship Arkansas , which was located in the immediate vicinity of the explosion zero point, was torn open over a large area by the underwater pressure wave, parts of the steering gear and drive shafts were torn off. It sank within a few seconds and has since been upside down on the sea floor at a depth of around 54 meters. The aircraft carrier Saratoga was badly damaged by the shock wave and sank, tail first, seven and a half hours after the test. Attempts were made to rescue them, but the heavy contamination of the ship and the lagoon water near the explosion center thwarted these attempts because the crews of the rescue ships should have been exposed to too great a danger. The Saratoga lies upright on the seabed, with its mast tip just 12 meters below the surface. The Japanese battleship Nagato capsized four and a half days after the test, on the night of July 30, unnoticed by all observers. The three sunken submarines Pilotfish , Skipjack and Apogon only left air bubbles and oil stains on the surface of the water. YO-160 , a concrete oil lighter , sank immediately after the explosion. The cruiser Prinz Eugen was badly damaged by the test, but was initially towed and brought to Kwajalein. There he capsized on the morning of December 22, 1946 because the heavy contamination made it impossible to repair the damage suffered. The armored landing craft LCT-1114 capsized in the explosion and was later sunk. Other target ships were badly damaged by the explosion, including the battleships New York and Nevada , the cruiser Pensacola , the destroyers Hughes and Mayrant , the troop carriers Fallon and Gasconade, and the armored landing ship LST-133 . The sinking of the Hughes and the Fallon was prevented by towing the ships ashore and beaching them.

Radiation exposure

After the Trinity test, the Baker test was the second nuclear explosion that occurred close enough to the earth's surface to keep the fission products in the local environment. In contrast to Able and the atomic bombs on Hiroshima and Nagasaki, it was not "self-cleaning". The resulting contamination was far more severe than any scientist predicted.

The Baker test produced around one kilogram of highly radioactive fission products, which corresponds to the radioactivity of several hundred kilograms of radium . These fission products were mixed with the 2 million tons of water and the material of the seabed and were now in the water and on the bottom of the lagoon. The vessels were the surge base heavily contaminated, near the center of explosion that was ion dose immediately after the explosion to the deck of the target vessels about 8000 X (80 Gray ) per day, which corresponds to the 80.000fachen the permissible radiation dose and 20 times the lethal dose.

Seafarers try to remove the radioactivity on board the Prinz Eugen with soapy water.

The first ships to sail the lagoon were remote-controlled drones, which enabled remote-controlled radiation and radioactivity measurements. They made it possible to localize the "hot spots" of the greatest radioactivity, which the other ships could then avoid. Due to the permissible radiation exposure of 0.01 X-rays per day, only the five ships furthest away from the center of the explosion could be safely entered. Some of the other ships could only be re-entered ten days after the test. Despite the high radiation levels, the Navy sent 4,900 men on board the ships in the first six days after the test, where they tried to wash off the radioactivity with brooms, soap and lye or to remove it with the help of sandblasting. The decontamination was made more difficult by the lack of education of the teams, a lack of protective equipment and repeatedly failing measuring devices for radiation monitoring. In addition, the "safe time" on board the target ships was temporarily only a few minutes, so the decontamination personnel had to be constantly changed. In addition, the radiological monitoring group complained of a chronic shortage of staff.

Another problem was that the neutron radiation produced large amounts of the radioactive sodium isotope 24 Na, which decayed with a half-life of almost 15 hours, but still contaminated the hulls and salt water systems of the ships in the accompanying fleet. In addition, there were just under five kilograms of plutonium from the bomb, which were not split and also lay on the ships with the local fallout and mixed with the water of the lagoon.

A 1996 study commissioned by the US government by the Institute of Medicine at the National Academy of Sciences showed that ex-participants in Operation Crossroads had a 4.6 percent increase in mortality. Specifically, at the end of the study period on December 31, 1992, 31.3 percent (12,520) of the military personnel involved in Operation Crossroads had died, while in the control group of the same age and size, 30.8 percent (12,320) had died. For the expected main causes of death for Crossroads veterans, i.e. diseases from leukemia and other cancers , the number of cases was not significantly higher than in the control group. This is contradicted by numerous cases of cancer in veterans of the test, which can almost certainly be attributed to increased radiation exposure during the first few days after the explosions.

Only a few pigs and rats were on board the target ships during the test. Since some of the ships could only be re-boarded after ten days, all pigs and almost all rats had died from the accumulated radiation dose by then.

Test Charlie

After the successful Baker test, Joint Task Force One went on to plan the third test, which was to take place at a depth of up to 1,600 meters below the surface of the sea and, according to Admiral Blandy's will, between March 1 and April 1, 1947 . Navy pioneers began preparing the anchorages for the target ships, while resistance to the test formed in Washington. General Groves in particular, who was critical of Operation Crossroads, began a personal campaign to stop Test Charlie. He publicly questioned the military and scientific necessity of the test. He also feared that another test of the Nagasaki-type implosion bomb would hinder the technical development of nuclear weapons in Los Alamos. After further discussions, also within the Evaluation Commission and the Joint Chiefs of Staff, Test Charlie was postponed indefinitely in a cabinet meeting on September 6, 1946. Massive budget cuts in the budget of the Army and Navy also favored the postponement. The $ 35 million Test Charlie was to cost was a substantial portion of the $ 1.6 billion the Army and Navy had to save. The indefinite postponement of the Charlie Test meant the end of Operation Crossroads, Joint Task Force One was officially disbanded on November 1, 1946.

After Operation Crossroads

A Navy fireboat tries to wash away contamination from battleship New York ; but since the lagoon water, which was also contaminated, was used, this was unsuccessful.

After attempts were initially made to decontaminate the target fleet in the Bikini Atoll lagoon, with some of the crew members being exposed to radiation well above the permissible limits, the decision was made on August 10 to relocate the entire fleet to Kwajalein , where a further contamination of the fleet by the radioactively contaminated lagoon water was excluded. The relocation was completed on September 26th when the last target ship left Bikini. The main task in Kwajalein was the unloading and cleaning of the ships; this lasted partially until 1947. Eight ships and two submarines of the target fleet were also brought to the US west coast and Hawaii, where further radiological examinations took place. Twelve target ships were only very slightly contaminated and could be put back into service and manned after decontamination and drove back to the United States under their own power. The remaining target ships were sunk as target ships off Bikini, Kwajalein or Hawaii between 1946 and 1948.

Most of the decontamination of the escort fleet took place in shipyards on the west coast, mainly in San Francisco. On some ships it was necessary to replace large parts of the pipe system of the salt water systems and to wash them out with acid. In addition, the entire underwater hull of many ships had to be sandblasted and repainted. As the last ship in the support fleet, the destroyer USS Laffey has existed as a museum ship to the present day.

A doctor fish caught alive after the nuclear test emits enough ionizing radiation to expose a film. The light area is algae that the fish ingested shortly before it was caught, but the rest of the body has also absorbed radioactive material.

The first scientific follow-up examination of the test took place in the summer of 1947. Under the command of Captain Christian L. Engleman, scientists from the Army, Navy, the Smithsonian Institution, the US Fish and Wildlife Service and several other scientific institutes examined the effects of the Baker test on marine life in Bikini Atoll and made a more detailed evaluation of the Damage to the sunken ships. The scientists arrived in the atoll on July 15, 1947 on board the USS Chilton , which was accompanied by the submarine rescue ship USS Coucal and the landing ships LSM-382 and LCI (L) -615 . September stayed. The effects of the underwater explosion were examined in over 600 dives to the wrecks of the Saratoga , Apogon and Pilotfish . The Nagato was also briefly examined. The dives were made more difficult by the poor visibility caused by the large amounts of fine mud at the bottom of the lagoon. This mud, which consisted for the most part of sand and corals destroyed by the pressure wave, was also partially highly radioactive, which is why the divers were extensively monitored radiologically.

In parallel to the dives, biologists examined the effects of the nuclear weapon explosions on marine life. Samples of the lagoon water and the coral reefs were taken to determine the level of radioactive contamination, and various creatures were captured so that they could later be examined for the effects of radioactivity. Geologists took drill samples from the lagoon floor to examine them. The results of the investigations were published in December 1947 as "Technical Report, Bikini Scientific Survey" by the Armed Forces Special Weapons Project.

In 1988 a second investigation of the wreck was suggested. On behalf of the United States Department of Energy, the National Park Service and the US Navy sent a team of researchers to carry out extensive investigations on the wrecks of the target fleet in Bikini Lagoon and on Kwajalein in July / August 1989 and April / May 1990 performed. Nine of the 23 ships sunk or sunk there were photographed, mapped and measured in detail, and measurements of the remaining radioactivity were carried out.

In 2008 an international expedition carried out a re-examination of the remaining radioactivity on Bikini. During the investigations, values in the interior of the islands were sometimes found to be three times higher than the permissible local dose rates , while the contamination on the beach and at the bottom of the lagoon is far below the limit values. However, the coconuts growing on the islands contain harmful concentrations of 137 cesium , some of which exceeded the permissible limit values ​​by 1.6 times.

Military consequences

One of the consequences of Operation Crossroads: ships of the US Navy were equipped with a countermeasure wash down system, which is supposed to wash away the fallout; here on board the USS Shoup .

The Evaluation Committee of the Joint Chiefs of Staff made a total of 18 conclusions on the military effectiveness of nuclear weapons in its final report on June 30, 1947. These included initial considerations on nuclear deterrence to ensure world peace and the effectiveness of the atomic bomb against cities, military facilities, and troop and ship concentrations. The committee finally formulated a total of twelve recommendations on what the future nuclear strategy of the United States should look like.

These included, in addition to the two-pronged strategy, on the one hand, to transfer nuclear weapons to non-governmental overriding control (which was never implemented in the USA, since both the United States Department of Energy and the United States Strategic Command are responsible for this) and, on the other hand, to a worldwide abolition of Nuclear weapons are also working towards recommendations to upgrade the US nuclear arsenal as quickly and as strongly as possible in order to be able to overwhelm potential opponents within the shortest possible time.

In addition, technical and medical procedures should be developed to ensure the survival of crew and ships after a nuclear attack. One of the technical measures included the development and introduction of the Countermeasure Wash Down System on board ships of the US Navy, which sprays both seawater and extinguishing foam from the fire extinguishing system onto the outer skin and deck of the ships via pipes and nozzles To either completely prevent deposits of radioactive precipitates on the ship's surface or at least to reduce them to such an extent that subsequent thorough decontamination can be carried out much more quickly and easily.

After protective measures against damage caused by the pressure wave were not appropriate because a sufficiently thick armor on the ships would limit their operational capability too much, the US Navy changed its basic doctrine and did not focus on strengthening the defense, but on the offensive use of nuclear weapons at sea . This included the development of sea-based ICBMs such as the UGM-96 Trident I , which can be fired from submarines and ships, as well as the development of anti -submarine weapons with nuclear warheads such as the Torpedo Mark 45 ASTOR .

Cultural and media reception

"As soon as the war ended, we located the one spot on earth that hadn't been touched by the war and blew it to hell."

"As soon as the war was over, we looked for the only point on earth that had remained untouched by the war and chased it to hell."

The Able test was observed by a total of 114 observers from the press, radio and video services. Most of them described the test as a failure because it did not meet expectations of the spectacular destruction of the entire target fleet. “ There were more explosions in that first [Red Sox] game at Fenway ” (German: “There were more explosions in the first Red Sox game in Fenway ”) complained a radio reporter from Boston , the New York Times headlined “ Blast Force Seems Less Than Expected ”(German:“ Explosive force seems less than expected ”). Also because of this disappointment, only 75 press representatives were present at the Baker test, but they were then presented with a "breathtaking sight", as Samuel Shaffer wrote for Newsweek . “ It left me staring open-mouthed. I was so moved I could hardly write intelligible notes ”(German:" It made me stare with my mouth open. I was so moved, I could hardly make intelligible notes ") wrote Philip Porter of the Plain Dealer , Cleveland's largest newspaper .

Admiral Blandy and his wife cut a cake in the shape of a mushroom cloud on November 7th.

If the press response after the Baker test was still positive, the image of Admiral Blandy and his wife cutting a cake shaped like a mushroom cloud caused harsh criticism, especially from the peace movement and the church. The picture, taken at a reception on November 7, 1946, to celebrate the end of Operation Crossroads, shows Admiral Blandy and his wife cutting an ornate sponge cake topped with a mushroom cloud modeled on the Baker test. Arthur Powell Davies , pastor of the Unitarian All Souls Church in Washington, DC , referred in his Sunday sermon on November 10th to the impression this image could make in the Soviet Union and on the survivors of the atomic bombings on Hiroshima and Nagasaki. He condemned the "obscenity" of the picture in the most violent way, and several newspaper columnists, including Walter Lippmann , joined him. The picture, which was featured in hundreds of newspapers and magazines, made Blandy "look like an idiot" and was a heavy blow to public relations work following the nuclear test.

One day after the Baker Test, the Soviet Union rejected the Baruch Plan , which provided for all nuclear weapons to be placed under international control. Andrei Andrejewitsch Gromyko informed the United Nations Atomic Energy Commission that "the proposal of the United States in its current form could in no way be accepted by the Soviet Union, either in whole or in part". The Soviet press accused the US of planning a war and Operation Crossroads was the "dress rehearsal". L'Unità , the mouthpiece of the Italian Communist Party , described Operation Crossroads as an "extremely alarming, monstrous and at the same time tragically grotesque experiment". The Avanti! put the nuclear armament of the United States on a par with the crimes of National Socialism .

The public received the first information about the extent of radioactive contamination of Bikini Atoll with the publication of a summary of the follow-up investigation in the summer of 1947. On August 11, 1947, Life magazine published a 14-page article about the effects of the tests on the lagoon and the experimental animals, dramatically highlighted with images of the effects on the internal organs. He concluded with a statement from the Head of Radiological Surveillance, Dr. Stafford L. Warren, who described the massive and unstoppable spread of fallout. But it wasn't until David Bradley's book "No Place to Hide", which appeared in 1948 and was recommended by The Atlantic Monthly , Reader's Digest, and Book of the Month Club , that the full extent was brought to light. Bradley, a member of the radiological oversight during the tests, stated that the true level of contamination of the ships and people involved in the tests was hidden behind a wall of military secrecy and "fancy numbers" were used to the public. His description of the tests made the public aware of the dangers and extent of nuclear fallout.

The best-known reception of the events during Operation Crossroads is the naming of the bikini swimsuit. Just two weeks after the Able test, on July 18, the fashion designer Louis Réard presented his two-piece swimsuit. The skimpy swimwear shocked the world as much as the nuclear test, which is why Réard decided on this name.

Two films dealt with Operation Crossroads: "Crossroads", a short film by Bruce Conner , which consisted of extremely slow-playing, high-speed recordings of the Baker Test, accompanied by a soundtrack by Terry Riley , and the documentary " Radio Bikini ", which was made in 1988 for the Oscar was nominated. Radio Bikini's main focus is on the fate of the indigenous population and their odyssey after resettlement.

The footage of the Baker Test is one of the best known recordings of a nuclear explosion and has been used in countless other media, such as in the closing sequence of Stanley Kubrick's film Dr. Strange or: How I Learned to Love the Bomb in the music video for Michael Jackson's Man in the Mirror , an episode of the sitcom Everyone Under One Roof , the thriller Deterrence, and the SpongeBob SquarePants episode Dying for Pie .

Fate of the bikinians

Official flag of the Bikini Atoll

The bikinians were resettled again in March 1948, homesickness for their homeland and the impending famine prompted the US authorities to first bring the natives from Rongerik to Kwajalein. As a new home, they then chose the previously uninhabited Kili Island , which was, however, too small to allow a self-sufficient way of life, so that the population was dependent on external supplies. In 1956, the US government paid initial compensation, with $ 25,000 being paid out to the bikinians, and a $ 3 million trust fund set up. In 1967 a study by the Atomic Energy Commission declared Bikini to be safe, so in August 1968 the first residents returned. In 1978, however, they had to leave the atoll again, as studies showed increased radiation concentrations in the coconuts, the main source of food. To this day, they have not been able to return to the island, as the pollution of coconuts and drinking water in particular do not allow a self-sufficient diet.

In 1975 the first trials began before the United States Supreme Court , where the bikinians are still fighting for adequate compensation and a complete decontamination of the atoll. The Bikini Atoll flag is a reminder of the bomb tests .

literature

  • David Bradley: No Place to Hide. University Press of New England, Boston MA 1946, new edition 1984. ISBN 978-0-87451-274-8
    German: David Bradley, Magda Larsen (ex.): Atomic bomb tests in the Pacific. Diana-Verlag, Baden-Baden and Stuttgart, 1951
  • William A. Shurcliff: Bombs at Bikini. The Official Report of Operation Crossroads. William H. Wise and Co Inc, New York NY 1947.
  • William A. Shurcliff: Operation Crossroads: The Official Pictorial Record . William H. Wise and Co Inc, New York NY 1947.
  • Jonathan Weisgall: Operation Crossroads. The Atomic Tests at Bikini Atoll. Naval Institute Press, Annapolis MD 1994, ISBN 1-55750-919-0 .
  • Stefan Terzibaschitsch : "Operation Crossroads". The US Navy nuclear weapons tests at Bikini Atoll in 1946. Podzun-Pallas, Friedberg / H. 1992, ISBN 3-7909-0462-7 ( Marine-Arsenal 20).

Web links

Commons : Operation Crossroads  - album with pictures, videos and audio files

Individual evidence

  1. a b c d Operation Crossroads: Fact Sheet . Naval Historical Center; As of December 3, 2015.
  2. ^ Stefan Terzibaschitsch: Operation Crossroads. The nuclear weapons tests of the US Navy at Bikini Atoll 1946 , in: Marine-Arsenal , Volume 20, Podzun-Pallas-Verlag, 1992. p. 5.
  3. a b c Operation Crossroads: Composition of Joint Task Force One . Naval Historical Center; As of December 3, 2015.
  4. WA Shurcliff: Bombs at Bikini. The Official Report of Operation Crossroads. Wm. H. Wise & Co., Inc, New York 1947. p. 36.
  5. Operation Crossroads: Target Ships Sunk During Test Able, July 1, 1946 . Naval Historical Center; As of December 3, 2015.
  6. Operation Crossroads: Target Ships Sunk During Test Baker, July 25, 1946 . Naval Historical Center; As of December 3, 2015.
  7. WA Shurcliff: Bombs at Bikini. The Official Report of Operation Crossroads. Wm. H. Wise & Co., Inc, New York 1947. p. 168.
  8. ^ A Short History of the People of Bikini Atoll ; As of March 28, 2010.
  9. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll. S. IX.
  10. WA Shurcliff: Bombs at Bikini. The Official Report of Operation Crossroads. P. 9.
  11. WA Shurcliff: Bombs at Bikini. The Official Report of Operation Crossroads. P. 10.
  12. Lewis Strauss: Men and Decisions . Garden City, New York: Doubleday 1962. pp. 208-209.
  13. a b c James P. Delgado: The Archeology of the Atomic Bomb: A Submerged cultural Resources Assessment of the sunken Fleet of Operation Crossroads at Bikini and Kwajalein Atoll Lagoons . National Park Service, Santa Fe, New Mexico 1991. p. 14.
  14. WA Shurcliff: Bombs at Bikini. The Official Report of Operation Crossroads. P. 11.
  15. WA Shurcliff: Bombs at Bikini. The Official Report of Operation Crossroads. Pp. 11-12.
  16. WA Shurcliff: Bombs at Bikini. The Official Report of Operation Crossroads. Pp. 12-13.
  17. Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 30.
  18. Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 126.
  19. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 67.
  20. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . Pp. 68-69.
  21. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 129 ff.
  22. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 127.
  23. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 216.
  24. James P. Delgado: The Archeology of the Atomic Bomb: A Submerged Cultural Resources Assessment of the sunken Fleet of Operation Crossroads at Bikini and Kwajalein Atoll Lagoons . Pp. 21-22.
  25. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . Pp. 157-158.
  26. ^ Leo Szilard, Spencer R. Weart, Gertrude Weiss Szilard: Leo Szilard: his version of the facts: selected recollections and correspondence . MIT Press Cambridge, Massachusetts 1978. ISBN 978-0-262-69070-6 . P. 184.
  27. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 90.
  28. James P. Delgado: The Archeology of the Atomic Bomb: A Submerged Cultural Resources Assessment of the sunken Fleet of Operation Crossroads at Bikini and Kwajalein Atoll Lagoons . Pp. 20-21.
  29. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 64.
  30. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . Pp. 91-92.
  31. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 252.
  32. a b Terzibaschitsch: Operation Crossroads. The US Navy nuclear weapons tests at Bikini Atoll in 1946 . P. 4.
  33. WA Shurcliff: Bombs at Bikini. The Official Report of Operation Crossroads. P. 125.
  34. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 122.
  35. Shurcliff: Operation Crossroads: The Official Pictorial Record . Pp. 65-68.
  36. Bauernfeind, Ingo: Radioactive to all eternity - The fate of the Prinz Eugen . ES Mittler & Sohn, Hamburg / Berlin / Bonn 2011, ISBN 978-3-8132-0928-0 , p. 70 .
  37. WA Shurcliff: Bombs at Bikini. The Official Report of Operation Crossroads. Pp. 51-52.
  38. WA Shurcliff: Bombs at Bikini. The Official Report of Operation Crossroads. P. 52 ff.
  39. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . Pp. 122-123.
  40. WA Shurcliff: Bombs at Bikini. The Official Report of Operation Crossroads. Pp. 16-17.
  41. WA Shurcliff: Bombs at Bikini. The Official Report of Operation Crossroads. Pp. 93-94.
  42. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 119.
  43. WA Shurcliff: Bombs at Bikini. The Official Report of Operation Crossroads. Pp. 94-95.
  44. WA Shurcliff: Bombs at Bikini. The Official Report of Operation Crossroads. Pp. 95-96.
  45. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 107.
  46. WA Shurcliff: Bombs at Bikini. The Official Report of Operation Crossroads. P. 93.
  47. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . Pp. 112-113.
  48. Shurcliff: Operation Crossroads: The Official Pictorial Record . P. 21.
  49. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . Pp. 18-19.
  50. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . Pp. 60-84.
  51. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . P. 67.
  52. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . P. 66.
  53. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . Pp. 67-69.
  54. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . P. 70.
  55. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . Plate 12.
  56. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . Pp. 76-77.
  57. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . Pp. 78-79.
  58. a b c Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 121.
  59. Michael Light: 100 Suns , 2003.
  60. Shurcliff: Operation Crossroads: The Official Pictorial Record . Pp. 72-73.
  61. Shurcliff: Operation Crossroads: The Official Pictorial Record . P. 75.
  62. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . Pp. 82-84.
  63. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . Pp. 98-99.
  64. a b c Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 120.
  65. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 175.
  66. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 176.
  67. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . Pp. 104-105.
  68. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . P. 105.
  69. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 185.
  70. Deutschlandfunk.de , calendar sheet , June 30, 2016, Dagmar Röhrlich : American atomic bomb tests began seventy years ago (July 2, 2016)
  71. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . Pp. 109-110.
  72. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . P. 117.
  73. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . Pp. 125-135.
  74. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . Pp. 189-190.
  75. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 189.
  76. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . Pp. 120-125.
  77. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . Pp. 140-141.
  78. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 204.
  79. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . Pp. 201-205.
  80. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 221.
  81. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 220.
  82. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . Pp. 220-221.
  83. a b Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . P. 151.
  84. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . Pp. 153-154.
  85. a b Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . Pp. 154-156.
  86. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . Pp. 160-162.
  87. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . Pp. 164-166.
  88. James P. Delgado: The Archeology of the Atomic Bomb: A Submerged Cultural Resources Assessment of the sunken Fleet of Operation Crossroads at Bikini and Kwajalein Atoll Lagoons . Pp. 60-64.
  89. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . P. 166.
  90. a b Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 227.
  91. James P. Delgado: The Archeology of the Atomic Bomb: A Submerged Cultural Resources Assessment of the sunken Fleet of Operation Crossroads at Bikini and Kwajalein Atoll Lagoons . P. 85.
  92. Shurcliff: Operation Crossroads: The Official Report of Operation Crossroads . P. 168.
  93. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . P. 230.
  94. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . Pp. 232-233.
  95. Jonathan Weisgall: Operation Crossroads: The Atomic Tests at Bikini Atoll . Pp. 233-234.
  96. James P. Delgado: The Archeology of the Atomic Bomb: A Submerged Cultural Resources Assessment of the sunken Fleet of Operation Crossroads at Bikini and Kwajalein Atoll Lagoons . P. 86.
  97. ^ A b Institute of Medicine: Mortality of Veteran Participants in the CROSSROADS Nuclear Test ; As of April 3, 2010.
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  113. ZDF Terra X: Radiant Atoll? Radioactive measurements 62 years after the atomic bomb tests ; As of April 4, 2010.
  114. Bikini Atoll - A radiant paradise? Researcher from Leibniz University Hanover documents radiation exposure on Bikini Atoll , press release from Leibniz University Hanover from November 16, 2009 at Informationsdienst Wissenschaft , status: December 3, 2015
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  133. bikiniatoll.com: US Reparations for Damages ; As of April 4, 2010.
  134. Bikini Atoll Flags of the World on the Bikini Atoll flag

Coordinates: 11 ° 36 ′ 0 ″  N , 165 ° 30 ′ 0 ″  E