What the mushroom cloud from 1952 hydrogen bomb test revealed

Sixty-nine years ago, a new type of cloud was the focus of scientific research: the mushroom cloud produced by cold war atomic tests.

Ivy Mike, which took place on 1 November 1952, was the first full-scale test of a hydrogen bomb. Equivalent to more than 10m tons of TNT, it obliterated the small island of Elugelab.

The rising fireball was accompanied by a spectacular display of lightning. This unusual “nuclear lightning” was a side-effect of the transient electromagnetic pulse from the nuclear blast.

Shortly afterwards, three USAF F-84 Thunderjets with sampling equipment flew into the stem of the boiling mushroom cloud. The first made it through without difficulty, the other two hit severe turbulence caused by the tremendous updraught, and lost control.

After recovering their planes, pilots Bob Hagan and Jimmy Robinson found their navigation instruments and radios had been disrupted by the electromagnetic pulse. They could not find their refuelling aircraft.

The two pilots ran out of fuel heading back Enewetak airbase. Hagan glided to a safe landing, but Robinson ditched in the sea and apparently drowned in the lead-lined vest supposed to protect him from radiation.

The US, UK and Soviet Union signed the partial test ban treaty in 1963, ending their above-ground tests and this type of hazardous meteorology.