Gerboise Bleue - The Most Powerful First Test A-bomb

The Most Powerful First Test A-bomb

With Gerboise Bleue, France became the fourth nuclear power, after the United States, the USSR, and the United Kingdom. Gerboise Bleue was by far the largest first test bomb up to that date, larger than the American "Trinity" (20 kt), the Soviet "RDS-1" (22 kt), or the British "Hurricane" (25 kt). The yield was 70 kilotons, bigger than these three bombs put together. General De Gaulle stated:

In comparison, Fat Man, the Nagasaki bomb, was 22 kilotons, one-third as powerful.

Only two other A-bombs tested in the Sahara facilities were more powerful: "Rubis" (<100 kt, 20 October 1963), and "Saphir" (<150 kt, 25 February 1965). Both were exploded underground at the Tan Afella facility.

All other French atomic-bomb tests, including Canopus, were done in French Polynesia from 1966 to 1996. The last bomb, Xouthos (<120 kt), was exploded on 27 January 1996.

As the atomic yield of a new bomb design cannot be precisely predicted, the French army planned an explosion between 60 and 70 kt. Gerboise Bleue was a total success, yielding the full designed power.