5km across, the fireball erupted from the island of Elugelab and engulfed the sky. The shock wave vaporised everything within 5km, and scraped the neighbouring islands clean, no buildings or plants remained. 2 hours later some helicopters flew over what used to be Elugelab. The island was gone. In its place was a dark blue welt in the ocean, 2km across, and deep enough to hold a 17 story building. The island had been vaporised. It was 1952, and the largest bomb in the world had just been detonated.
The United States made the bomb because it was afraid. In late 1949 the Soviet Union had created and detonated ‘First Lightning’ – a nuclear bomb just like those dropped at the end of World War II. The United States was no longer the only nuclear superpower. Tensions escalated, and they needed something new. They were going to need a bigger bomb.
In January 1950, President Truman announced that the United States would develop a new bomb, superior to the A-bomb. A hydrogen bomb that would push the United States into the Thermonuclear era. Unfortunately nobody knew how to make the H-bomb.
H-bombs are thermonuclear, meaning nuclear fusion. They make heat in the same way the sun, and billions of others stars make their energy. Two small atoms like hydrogen hit each other and combine to make a larger atom, at the same time they release large amounts of energy. The problem is that fusion needs immense heat and pressure. That difficulty is why it was happening easily in the sun, but not so much on Earth.
In 1951 Stanislaw Ulam and Edward Teller overcame that barrier. With their combined ideas, thermonuclear bombs were possible – in theory. To test the theory, they needed an experiment. Project Ivy was started, and it was the perfect opportunity to test.
The Building Bomb
Project Ivy was aimed at improving U.S. nuclear weapons in two ways. The first was the H-bomb, the other was making a larger, A-bomb. The H-bomb was Ivy Mike, at its construction it was the largest, heaviest and most powerful bomb in existence. I say bomb, it was closer to a factory-sized nuclear fridge.
Mike was not a bomb ready to be dropped from a plane, it was designed purely as an experiment, so it looked like an aircraft hangar or factory. It was assembled in the Pacific proving grounds, on Elugelab, a small island on Enewetak atoll. The main bomb assembly was over 6 metres tall and 2 metres wide. Covered in metal case 30cm thick, it was very large, shiny and cold. They nicknamed it “Sausage.” Sausage weighed a dainty 56 metric tonnes.