1962 Operation Dominic.

Operation Dominic was a series of 31 nuclear test explosions with a 38.1 Mt (159 PJ) total yield conducted in 1962 by the United States in the Pacific. This test series was scheduled quickly, in order to respond in kind to the Soviet resumption of testing after the tacit 1958–1961 test moratorium. Most of these shots were conducted with free-fall bombs dropped from B-52 bomber aircraft. Twenty of these shots were to test new weapons designs; six to test weapons effects; and several shots to confirm the reliability of existing weapons. The Thor missile was also used to lift warheads into near-space to conduct high-altitude nuclear explosion tests; these shots were collectively called Operation Fishbowl.

https://en.wikipedia.org/wiki/Operation_Dominic