On August 10, 1945, a handwritten note on a major wartime document placed an additional restriction on the atomic age, which was: “It is not to be released over Japan without express authority from the President.” The line, drawn on directions regarding the next weapon, lies like a brake-mark on a road made to be run up that even, though production was increasing, control of the bomb was being hauled upwards and drew in.
That momentum became achievable thanks to the industrial geography of the Manhattan project. At Hanford, plutonium was bred in reactors, at Oak Ridge uranium enrichment was increased, at Los Alamos engineers and physicists were transforming rare materials into working weapons. Those productions had yielded “Little Boy” to Hiroshima and “Fat Man” to Nagasaki, when the system was not intended to cease at two. Another of the series of implosions, another kind of “Fat Man,” was already in progress, and Los Alamos technicians had around-the-clock work to cast and complete plutonium nucleus.
That central part became later notoriously known as the demon core, but in mid-August 1945 was merely the following constituent in a row. An intelligence report indicated the existence of a weapon that could be delivered by mid-month, and a letter between General Leslie Groves indicated “the next bomb … should be ready for delivery on the first suitable weather after 17 or 18 August.” The demeanor of the administration was disguising an important change: the initial applications of the atomic bomb had been authorized in an “as made ready” logic, but the margin note that accompanied the next step stated that automatic release was no longer available.
The name of one city, which is hardly generated in the retelling of the popular accounts, assists us to understand how conditional was the planning. The port city of Niigata on the northwestern coast of Honshu was listed as a “B Target” with a lower priority given in committee note as a site with machine tools, oil refineries and storage. But Niigata too revealed a practical limitation which interested aircrews more than historians: distance. Relative to the more compact Kokura, Nagasaki and Hiroshima, Niigata was far off, a fact that influenced the fuel calculations when B-29s would be launching missions with extremely high loads. That is, the presence of the third weapon did not necessarily become, as a matter of fact, a clean, pre-printed destination; the weather, the range, and the control of forces were all packed into the decision space.
It was another talk which ran behind those who attacked debates, what kind of demonstration, no matter how many, could bring to a close a war without the burning of a city. A noncombat display awaited a single hearing in late spring 1945 by an Interim Committee which, due to practical considerations, fear of a dud, fear of being intercepted, fear of the shock weakening, rejected the proposals. This reasoning on the committee led to a preference of a resounding goal, an industrial plant enclosed by houses, the goal being as much a psychological effect as an industrial destruction one. The so-called engineering promise of the weapon, compactness, unprecedented release of energy, could not be discussed outside of the context of the strategy of surprise.
In cases where the third strike was not made the plutonium core story fled inside, to the laboratory. Experiments on the same material destined to be a bomb were also stored, nicknamed “Rufus,” and subsequently “the demon core” following two fatal criticality incidents at Los Alamos. Physicist Harry Daghlian in one instance was given a fatal dose when a tungsten-carbide brick fell onto the core; and physicist Louis Slotin was killed when two hemispherical reflectors closed too far around it when a screwdriver slipped. Thereafter the practices of criticality testing were altered and the core itself, which is too radioactive to be used in planned application, was melted down and later used to become part of subsequent warhead material.
We have lost the third strike, and not as a footnote to the two detonations, but as a kind of revelation: the industrial capacity had outrun the policy, the lists of targets on which he had geography and bureaucracy printed in them, the object in the middle, one shaped piece of plutonium, which not even out of the lab was safe.
