Command and Control

During his visit to New Mexico, Lilienthal also discovered a shortage of scientists trained to make atomic bombs. The physicists, chemists, and engineers who’d put together the bombs at the end of the Second World War were now scattered throughout the United States. The Mark 3 implosion bomb was, in Oppenheimer’s words, a “haywire contraption,” difficult and dangerous to assemble. But at least some of the scientists in Los Alamos still knew how to make one. Nobody had bothered to save all the technical drawings necessary for building another Little Boy, the uranium-based, gun-type bomb dropped on Hiroshima. The exact configuration of the various parts had never been recorded on paper — an oversight that, amid the current shortage of plutonium, created some unease. As files and storerooms at Los Alamos were searched for information about Little Boy’s design, a machinist offered to demonstrate how one of the bomb’s aluminum tubes had been forged. He’d wrapped the metal around a Coke bottle.

After the war, the Z Division at Los Alamos, which had designed the firing and fuzing mechanisms of both atomic bombs, was moved an hour and a half south to an old Army air base near Albuquerque. The Z Division’s headquarters was soon renamed the Sandia Laboratory, and a new military outfit called the Armed Forces Special Weapons Project (AFSWP) was located at the base, too. When the production of Mark 3 bombs resumed, the work was now divided among three organizations: Los Alamos fabricated the cores and the explosive lenses; Sandia was responsible for the rest of the weapon; and the AFSWP trained military personnel how to complete the assembly in the field. Norris Bradbury, the director of Los Alamos, pushed for improved designs that would make atomic bombs simpler, smaller, lighter, and safer to handle. It would take years for such improvements to be made. Until then, the safety of America’s nuclear weapons depended on checklists, standard operating procedures, and a laboratory culture with a low tolerance for mistakes.

Bradbury worried about what would happen if a B-29 bomber crashed in the United States while carrying a fully assembled Mark 3 bomb. The B-29 had a high accident rate — two had crashed and burned on the runways at Tinian while trying to take off the night before the bombing of Nagasaki. In 1947 the Armed Forces Special Weapons Project decided that the final assembly of Mark 3 bombs must always occur outside the United States. The reliability of the weapon’s electronic, mechanical, and explosive components was unknown, and Bradbury thought that a crash during takeoff would pose “a very serious potential hazard to a large area in the vicinity.”

The Mark 3 was considered too dangerous to be flown, fully assembled, over American soil. But no safety restrictions were imposed on flights of the bomb over Great Britain. Atomic bomb — making facilities were secretly constructed at two Royal Air Force bases, in Sculthorpe and Lakenheath. Before attacking the Soviets, American B-29s would leave the United States with partially assembled Mark 3s and land at the British bases. Plutonium cores would be inserted into the weapons there, and then the B-29s would head for their Soviet targets. If one of the B-29s crashed during takeoff, the RAF base, as well as neighboring towns, might be obliterated. Anticipating that possibility, the U.S. Air Force explored sites in the countryside of Norfolk and Suffolk where atomic bombs could be hidden, so that “if one blew, the others would survive.”

During the AFSWP’s first attempt to assemble an atomic bomb, it took a team of thirty-six men two weeks to finish the job. That did not bode well for a quick retaliation against a Soviet attack. Through constant practice, the assembly time was reduced to about a day. But the Mark 3 bomb had a number of inherent shortcomings. It was a handmade, complicated, delicate thing with a brief shelf life. The electrical system was powered by a car battery, which had to be charged for three days before being put into the bomb. The battery could be recharged twice inside the Mark 3, but had to be replaced within a week — and to change the battery, you had to take apart the whole weapon. The plutonium cores radiated so much heat that they’d melt the explosive lenses if left in a bomb for too long. And the polonium initiators inside the cores had to be replaced every few months. By the end of 1948, the United States had the necessary parts and cores to assemble fifty-six atomic bombs, enough for an atomic blitz. But the Armed Forces Special Weapons Project could deploy only one bomb assembly team overseas. It would take months for that team to put together so many atomic bombs — and a stray wire, some static electricity, or a little mistake could end the entire operation in a flash.

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