Ivy Mike was the codename given to the first full-scale[note 1] test of a thermonuclear device, in which a significant fraction of the explosive yield comes from nuclear fusion.

[4] Due to its physical size and fusion fuel type (cryogenic liquid deuterium), the "Mike" device was not suitable for use as a deliverable weapon.

[5] Beginning with the Teller–Ulam breakthrough in March 1951, there was steady progress made on the issues involved in a thermonuclear explosion and there were additional resources devoted to staging, and political pressure towards seeing, an actual test of a hydrogen bomb.

[8]: 482  On June 30, 1952, United States Atomic Energy Commission chair Gordon Dean showed President Harry S. Truman a model of what the Ivy Mike device would look like; the test was set for November 1, 1952.

[6]: 145–148 There was a separate desire voiced for a very short delay in the test, for more political reasons: it was scheduled to take place just a few days before the 1952 presidential election.

[8]: 497  Truman wanted to keep the thermonuclear test away from partisan politics but had no desire to order a postponement of it himself; however he did make it known that he would be fine if it was delayed past the election due to "technical reasons" being found.

Garwin was instructed to use very conservative estimates when designing the test, and told that it need not be small and light enough to be deployed by air.

[11]: 327 Liquid deuterium was chosen as the fuel for the fusion reaction because its use simplified the experiment from a physicist's point of view, and made the results easier to analyze.

From an engineering point of view, its use necessitated the development of previously unknown technologies to handle the difficult material, which had to be stored at extremely low temperatures, near absolute zero.

Elugelab was connected to the islands of Dridrilbwij (Teiteir), Bokaidrikdrik (Bogairikk), and Boken (Bogon) by a 9,000 ft (2.7 km) artificial causeway.

Radioactive coral debris fell upon ships positioned 56 km (35 mi) away, and the immediate area around the atoll was heavily contaminated.

[32] He was able to receive first notice that the test was successful by observing a seismometer, which picked up the shock wave that traveled through the earth from the Pacific Proving Grounds.

[33][8]: 777–778  In his memoirs, Teller wrote that he immediately sent an unclassified telegram to Dr. Elizabeth "Diz" Graves, the head of the rump project remaining at Los Alamos during the shot.

In rain and poor visibility, without working instruments, Hagan and Robinson were unable to find the KB-29 tanker aircraft to refuel.

[5] Al Ghiorso at the University of California, Berkeley speculated that the filters might also contain atoms that had transformed, through radioactive decay, into the predicted but undiscovered elements 99 and 100.

Ghiorso, Stanley Gerald Thompson and Glenn Seaborg obtained half a filter paper from the Ivy Mike test.