On 1 July, the American military began operation Crossroads - the second series of atomic weapon tests which was designed to assess the effect of bombs on ships.

Two explosions with a capacity of 23 kilotons were planned. The bombs were copies of the “Fat man” nuclear bomb, which had been detonated over the Japanese city of Nagasaki. The first test, “Able”, took place on 1 July when a bomb, decorated with the image of film star Rita Hayworth, was detonated from a height of 158m.

Representatives of the press and observers from foreign countries had been invited to the Marshall Islands including, from the USSR, Mikhail Grigorievich Meshcheryakov - head of the cyclotron laboratory of the Radium Institute of the USSR Academy of Sciences - Professor S P Alexandrov, USSR expert from the United Nations Atomic Energy Control Commission and Alexey M Khokhlov, a captain of the 2nd rank and head of the Central Research Institute’s design department, although for the purposes of the visit he had been declared a correspondent of the newspaper “Krasnaya Zvezda” (Red Star).

The decision to destroy ships worth $450 million, namely, four battleships, two aircraft carriers, 11 destroyers, eight submarines, and numerous auxiliary ships aroused protests. However, US Admiral William Blandy replied that their only value was as scrap, i.e. $10 per ton.

In the first test, the expanding gas bubble captured 2 million tons of water and sand, and formed a column which was almost 2km high (1,829m), and more than half a kilometre in diameter (610m), forming a hemispherical “Wilson cloud”.

Five ships were sunk: two landing crafts went down immediately, two destroyers took an hour to sink and a Japanese cruiser took a day. The damage to the ships had been expected to be greater, but the bomb fell away from the target point because of the bomb’s curved stabiliser.

The second part of the tests was scheduled for 25 July.