RDS-1 / “JOE-1” Test

In April 1946, the USSR began its nuclear program at the Kurchatov Institute while the production of plutonium for the test was carried out at the Chelyabinsk-40 industrial complex. Aside from the own investigations, it is known that the Soviets received abundant information about the American “Trinity Project” from the German scientist Klaus Fuchs, who had fled from Nazi Germany and sympathized with the communist ideology. The program was baptized as RDS-1, Izdeliye 501 or “First Lightning” although the United States designated it as “Joe-1” in relation to Josef Stalin. The RDS-1 was an implosion device with a plutonium core, similar to that used by Americans in the Trinity device and the “Fat Man” nuclear bomb of proven reliability. On the test site several buildings were built, trucks, planes and various vehicles were  left in the area. Even 1,000 animals were released in the area to analyze the effects of the explosion on their bodies. The test was carried out on August 29, 1949 at 7:00 a.m. at Semipalatinsk test site, Kazakhstan, and it was a complete success. It was estimated that the 22kt power explosion was a 50% more powerful than expected. In total, five RDS-1 tests were carried out until March 1950, and the production of bombs with this warhead began in December 1951.

RDS-1 / JOE-1 test gallery and more info


Información adicional

Ficha Completa
Country of origin

Soviet Union


Atmospheric test


August 29, 1949 at 07:00 GMT

Warhead, (explosive charge)

Fissile material: Plutonium core – Type: fission implosion device

Yield, (maximum)

22 Kilotons