Thread by @AtomicAnalyst

Seventy-five years ago today (9:00am local time), the United States conducted its first post-war atomic test—Shot Able of Operation Crossroads. A B-29 bomber dropped a Fat Man-type 23-kiloton bomb over an array of 95 ships moored in Bikini Atoll lagoon. 

To prepare for Operation Crossroads (originally planned as three tests), in March 1946, the US forced 167 native islanders living on Bikini Atoll to relocate to Rongerik Atoll 128 miles to the east. To make room for the ships, it used 90 tons of dynamite to destroy coral heads.

Due to a bombsight miscalibration, the bomber missed its intended aim point—the brightly-painted battleship USS Nevada (number 32 on the map)—by 2,130 feet, and the bomb instead exploded close to the attack transport USS Gilliam (number 5 on the map).

Here’s silent footage of some of the more than 40,000 sailors who participated in Operation Crossroads practicing for the moment of the explosion and then observing the resulting mushroom cloud at a distance: 

The bomb was adorned with a photograph of actress Rita Hayworth and a stencil of the title of her then-hit movie, “Gilda.” Hayworth’s husband, Orson Welles, said he hoped his daughter could tell her daughter “that grandmother’s picture was on the last atom bomb ever to explode.”

For the complete story on that fascinating aspect of the test, see conelrad.blogspot.com/2013/08/atomic….