ONE

THE BOMB SAT in its cradle in the assembly hut, six inches off the concrete floor at its lowest point, sixty-six inches at its highest. Ensign Don Mastick walked into the hut and saw Arthur Machen straddling the rear end of the 10,300-pound plutonium weapon, working feverishly to file down a hole in the bomb’s tail assembly, which was suspended in front of him from a block and tackle.

“Hey, cowboy, what the hell are you doing?” Mastick hollered to the bomb assembly technician.

Sweat poured down Machen’s forehead, even though he was in the only air-conditioned building in the Pacific. He was racing against time, and filing through the .2-inch-thick aluminum plate was proving to be excruciatingly difficult. The Bock’s Car, the B-29 that would carry this weapon to the target in its bomb bay, was scheduled to take off in a few hours.

The tension and exertion were taking their toll on the young scientists and technicians of Project Alberta who anxiously watched Machen’s progress. They were the representatives on Tinian Island from the Manhattan Project who were responsible for the assembly, arming, and loading of the weapon on board the Bock’s Car. Any delay might cause the mission to be scrubbed, a prospect they did not want to entertain. Too many lives hung in the balance.

“Son of a bitch,” whispered Machen as he wiped away the sweat, trying to keep his eyes clear. He didn’t hear Mastick.

Earlier in the day, the delicate internal mechanism of the Fat Man had been carefully set into the bomb casing and the two spherical halves had been bolted together. Work had progressed slowly and methodically on this complicated nuclear weapon, which contained fifty-three hundred pounds of Composition B and Baratol, high-grade explosives, laid out in a precise configuration around an eleven-pound sphere of plutonium. This quantity of high explosives made Fat Man the most powerful bomb in the Pacific theater, even without the plutonium. A single spark could detonate the explosives, and in a flash, destroy the entire compound in which the assembly building sat.

The tail assembly—“the California parachute”—which would allow the bomb to drop on a predictable and stable trajectory, was about to be attached to the bomb’s skin as the final step before transport of the bomb to the loading pit on the flight line. But as Machen had moved the tail section to jigger it into place, he was stunned to see that the upper hole on the tail didn’t match its counterpart on the casing. They weren’t aligned! Although the holes were off by only a fraction, maybe a hundredth of an inch, it was enough to keep the bolt from going through.

Maybe it was a mechanic’s error. Or maybe the heat and humidity on Tinian had caused the metal to warp. But whatever the reason, after two billion dollars’ worth of research by the best minds in the world, years of top secret military planning, and the combined efforts of hundreds of thousands of people, at the eleventh hour a technician was relying on a $1.98 rat-tail file and brute force to finish assembling the first plutonium bomb that would be dropped from an airplane.

This was to be the first of many surprises and near misses that would plague my mission to Nagasaki and test the dedication and skills of my flight crew and me.

I hadn’t gotten much sleep since our return from Hiroshima on August 6. Colonel Paul Tibbets had told me on that evening that I would command the second atomic mission, on August 9, if a second drop was necessary. With barely enough time to recover from and reflect upon the Hiroshima mission, my crew would be flying another atomic strike in less than three days. It would be my first combat mission command.

I sat alone on a hilltop overlooking the massive runways on the northern tip of Tinian. The sky overhead was ink-black. Not a star was in sight. In a few hours we would be taking off from these runways. The men from Project Alberta were completing the final assembly of the Fat Man. This would be no concrete-filled “pumpkin” of the sort we had practice-dropped from our B-29s over the salt flats of Utah for the past several months. Our cargo would be live, with an expected explosive yield calculated to be equivalent to at least 46 million pounds of TNT.

This bomb would be the first weapons system ever used by the United States that had not been extensively field tested. Only one other plutonium bomb had ever been detonated, and that had been a static test in the middle of the desert in the Southwest with the bomb sitting secure on a tower, connected by wires to a command center several miles away near Alamogordo. In a few hours, we were going to drop a similar weapon from an airplane, where it would free-fall from 30,000 feet—with no wires attached. Although the scientists had ingeniously designed the physics package to fit within the confines of a bomb ten feet long and five feet across, none of them was sure exactly what the bomb would do. They expected it would be more powerful than the uranium bomb, the Little Boy, dropped over Hiroshima. But that was about it. How much more powerful? They weren’t sure. Some thought it was possible our airplane would be blown out of the sky. Others speculated that a chain reaction that could destroy the world might be triggered. A few weren’t even certain it would work.

I began going over in my mind every step of Colonel Tibbets’s mission to Hiroshima. It had gone like clockwork. Perfect weather—not a cloud in the sky. Perfect execution—no fighter intercepts or antiaircraft fire at the target. Bomb away within seventeen seconds of the scheduled release—and a bull’s-eye on the target. Then a flawless return to Tinian. It was up to me to live up to his expectations for this crucial second mission. He had chosen me to carry it out. I had to succeed.

“We must make the Japanese believe we can keep them coming every few days until they surrender,” the colonel had told me. In truth, there was no third bomb behind us ready to go.

There had been no word of surrender from the Japanese after the bombing of Hiroshima, so I knew that our hope of quickly ending the war depended on this mission. After witnessing the blast at Hiroshima, I believed Japan would finally surrender. But her military seemed prepared to continue in a glorious and suicidal defense of the mainland. We were getting closer to the invasion of Japan, which was scheduled to begin on November 1, and the prospect of hundreds of thousands more American casualties in an invasion was not just some abstract concept to me—it was a sobering reality.

I focused on the steady flow of B-29s taking off from the runways below into the darkness for their firebombing missions over Japan. The burned-out hulks of the planes that never made it off the ground on earlier missions lay in the shadows of the runways. A lot of good men had died in them.

My mind drifted back to my last trip home in late 1944. By sheer coincidence, my friend Colonel Jim McDonald, with whom I had gone through flight school before the war, was home, too. Jim had just completed twenty-five B-17 missions over Europe with the Eighth Air Force. There were very few B-17 crews who survived the twenty-five-mission rotation. I knew that I would soon be going overseas, and since I had no combat experience, I was anxious to learn what advice my old pal might give me.

We met for dinner at the Parker House, on the corner of Tremont and School streets, on a snowy evening in downtown Boston. Jim was six years older than I. He had been just below the maximum age and I just over the minimum age when we entered flight school in the spring of 1941. Jim had advanced to become a lead pilot in Europe, which meant that he led the formations of bombers into the target. It was a job that required skill, courage, and maturity.

We were seated in the ornate, mahogany-paneled main dining room. Waiters in crisply starched aprons moved about on the thick carpets without a sound. Jim and I reminisced over drinks and sirloin steaks. At one point, I told him I would be going into combat with a bomb group. Secrecy precluded my mentioning anything other than conventional aerial warfare. I asked him what advice he could offer me. Anything special I should know? Any mistakes I should avoid?

He thought for a moment and then answered with a smile, “Promote your men as fast as you can.”

We both laughed. Then he turned serious, leaned in toward me, and in a precise, slow cadence said, “Never go over a target a second time. Never! If they didn’t get you the first time, they’ll get you the second time around with antiaircraft fire or fighters.”

The activity on the runway below pulled me back. I caught sight of a B-29 lumbering down, laden with a full load of high-test aviation fuel and incendiary bombs. It appeared to be struggling to make it into the air. It was overloaded. It did get up for a moment, then hung in the air before plunging into the ocean. A burst of flames erupted in the darkness. The sounds of explosions punctuated the night.

Rescue boats stationed offshore sped instantaneously to the scene. Standby emergency vehicles moved in. There would be little they could do to stop the napalm spilling from the exploding ordnance from fueling the fire.

It was not the first or the last B-29 I would see crash on takeoff at Tinian. These ten Americans would be added to the statistics of the war—a war we had not started and did not want.

“No second runs,” I murmured aloud, as if reciting instructions. But first things first. I’d have to get the plane into the air. In a few hours my crew and I would be rolling down one of these runways with a bomb and extra fuel that would put our airplane thousands of pounds over the manufacturer’s specifications for maximum takeoff weight. With all that weight, we’d barely have enough runway to reach the proper air speed for liftoff.

Further complicating matters, our bomb, because of its complex detonation system, would be armed when it was loaded into our bomb bay, unlike the Little Boy, which had been unarmed on takeoff. The Enola Gay could have hit a brick wall and the bomb probably would not have detonated. For us, a crash on takeoff could vaporize my crew, Tinian, and me. But as I looked down on the runway, I had total confidence that I would get the airplane into the air and on to Kokura, Japan, our primary target.

I stood up to leave. At that moment I had no idea that my crew and I were about to confront a series of problems that would start at the moment of takeoff and continue until our forced emergency landing at an unplanned location ten hours later—any one of which could have doomed us and our mission and hundreds of thousands more in a prolonged war.

It was time to go.