109 East Palace (46 page)

A meteorologist named Jack Hubbard had joined the staff and was heading a team that was closely monitoring the weather conditions for the days surrounding the test. Clear weather was vital to the experiment and to their ability to get accurate measurements from their instruments. Rain, either before or during the test, could damage the electrical circuits and operating equipment, interfering with the firing of the bomb and wrecking havoc on their instruments. There was also the potential problem of fallout. One of the main reasons they had decided to explode the bomb from the top of a one-hundred-foot tower was that a ground detonation, in addition to not really revealing what it could do as a weapon, would create a tremendous amount of fallout at a low elevation. There was a possibility that strong winds in the wrong direction could carry the poisonous radioactive cloud over inhabited areas, most notable Amarillo, which was about three hundred miles away. Very little was known about fallout, but they could not ignore the potential danger, and evacuation teams were being organized. Drawing on information from myriad sources, including the Army Air Forces weather stations at Alamogordo and Albuquerque, Hubbard finally pinpointed the middle of July as the best time to test the gadget.

On the last day of June, all the division leaders reported to Oppenheimer, and it was decided that July 16 was the earliest possible date they could be ready Groves, however, was determined that Truman would be armed with knowledge of the test’s outcome when he met with Stalin and Churchill at the Potsdam conference, which Stimson, dragging his feet all the way, had managed to delay until July 15. The first week in July, with the Potsdam deadline looming, Groves fixed the final test date for July 16. He was pushing up hard against Hubbard’s long-range prediction for that weekend, which did not look promising, but that was a chance they would have to take. Oppenheimer instructed the Trinity team that orders from Washington were that as soon as the plutonium for the bomb was ready, the test would go forward. There must be no delays. As Bainbridge noted, “A successful test was a card which Truman had to have in his hand.” Because of all the uncertainty, Groves took off for the Hanford site, taking Bush with him. They would meet up with Conant on the Pacific Coast. “This would enable us,” Groves wrote, “to get to Alamogordo promptly if the date of the test was advanced.”

In the days immediately preceding the test, dozens of high-ranking project consultants and Nobel laureates returned to Los Alamos: Richard Tolman, Ernest Lawrence, Isidor Rabi, Sir James Chadwick, and, making another appearance the day before the test, Bill Laurence, the sole member of the press assigned to document the event. Groves, warned not to invite too many observers, well exceeded his ration, and at the last minute Dorothy had to scramble to find sleeping quarters for an extra general. He had requested a room at La Fonda, but the hotel was overbooked. “Not only did he have to settle for a second choice billet at the De Vargas hotel,” she recalled, “he had to share a double room with a sergeant.” She told him what she told everybody, “You know, there’s a war on!” Memos came down from the Hill daily with eight or nine new names to expect, and calls came from Washington saying, “We have the following coming in….” There were so many people coming and going that a number of G-2 agents worked in the office helping her check papers and issue security passes.

One afternoon, Dana Mitchell, who had worked at 109 with Dorothy in the early days of the project, stopped by to make an important call. Dorothy politely stepped into the other room to give him some privacy, but he did not seem to notice. She overheard him tell someone in a voice that was louder and more strident than usual that they had “ambulances ready in Albuquerque” in case they were needed. Dorothy knew then that things were moving very fast. “Time, time, time. Speed, rush. Care, care, and worry,” she wrote. “Anxiety and work. All hours of the day and night, not sleeping, not eating regularly, losing weight. Always tension, excitement, pride, rising in the great crescendo of the test at Trinity.”

SEVENTEEN

Everything Was Different

I
N
J
ULY, THE RAINS CAME.
At midday, bright blue skies would suddenly darken as black clouds amassed overhead, lightning streaked across the sky, and thunder cracked with frightening violence. Brief, soaking downpours followed. Everyone on the Hill had become obsessed with the unpredictable midsummer weather patterns. Physicists with no particular expertise in meteorology would scan the cloudless horizon with furrowed brows as if they could divine signs of trouble. Even men who were usually careful not to talk about their work told their wives to pray for a good forecast.

Doubt and pessimism blew into town with the thunderheads. There was a prevailing skepticism in the air, as if the scientists could not believe the witching hour had arrived and that the bomb’s fearful power would prove all their experiments and calculations correct and finally put an end to their long endeavor. Instead, they distrusted their own handiwork and took refuge in the idea that the Trinity test’s many uncertainties would probably result in a fizzle. Their lack of faith was never clearer than when some of the physicists organized an informal betting pool to see who could most accurately predict the explosive yield of the bomb. Their own blackboard estimate put the gadget’s potential at roughly 20,000 tons, or 20 kilotons, of TNT, but the pool ran from zero to 45,000 tons. Rabi bet 18,000 tons. Bethe guessed 8,000 tons. Kistiakowsky thought the figure would be closer to 1,400. Oppenheimer conservatively settled on 300. But his was not the lowest bet: Johnny Williams figured on 200 pounds, and more than a few pessimists thought it would be zero. It was Teller, who had done the least direct work on the bomb and had the least at stake, who unhesitatingly went for the biggest bang—45,000 tons.

They were all so consumed with their own worries that the news that Feynman’s young wife, Arline, had passed away put them all to shame. Richard had borrowed Fuchs’ car and managed to get to Albuquerque in time to be at her side and say good-bye. Dorothy heard that he was in such a rush to get to the hospital that he got not one but two flat tires and ended up hitchhiking the last thirty miles. Distraught as he was, Feynman returned to his Tech Area office the next day and told people he intended to bury his sorrow in work.

“That last week in many ways dragged,” recalled Elsie McMillan, and “in many ways it flew on wings. It was hard to behave normally; it was hard not to think; it was hard not to let off steam. We also found it hard not to overindulge in all natural activities of life.” She had long ago guessed that the Trinity test was for an atomic bomb and now asked her husband, “in all innocence,” what would happen. She needed to know. Not knowing was worse, and she was afraid she was transferring her mounting fears to her newborn son, as she rocked him to sleep in her arms.

Slowly, and with some difficulty, Ed McMillan told her what he thought she could expect. “There will be about fifty of us present, the key workers,” he explained.

We ourselves are not absolutely certain what will happen. In spite of calculations we are going into the unknown. We know that there are three possibilities: One, that we will be blown to bits if it is more powerful than we expect. If this happens you and the world will be immediately told. Two, it may be a complete dud. If this happens, when I return home I will tell you. Third, it may as we hope, be a success, we pray without loss of any lives. In this case, there will be a broadcast to the world with a plausible explanation for the noise and the tremendous flash of light which will appear in the sky. Next week we will quietly and separately leave the mesa starting around 3:00
A.M.
, the cars to reconvene at the test site. In all probability the zero hour will be about 5:00
A.M.
on the morning of the next day. If all goes well, I will be home sometime in the early evening of that day.

At the end of the day on Wednesday, July 11, Oppenheimer gave some final instructions to his secretary, Anne Wilson, tucked an extra carton of cigarettes under his arm, and took off for Trinity. “I thought I was queen for a day because he left me in charge of the whole place,” she said. “I thought he was mad because I was all of 21. Everyone who was anyone was going to the test. They piled into buses and left in droves, and I would go out into the street in front of the Tech Area and wave goodbye to them.”

On Thursday, July 12, the explosive casing for the test bomb was finished. For safety reasons, the nuclear and non-nuclear parts of the bomb would be moved separately and then assembled at the Trinity site. Just “to be whimsical,” Kistiakowsky decided to transport the finished bomb assembly from Los Alamos to Trinity on Friday the thirteenth, hoping such bravado would reverse the date’s traditional bad luck. They took off at ten minutes past midnight, a whole convoy of trucks, including the one carrying the gadget, a big spherical aluminum ball, carefully tethered in place and covered by a concealing tarp. Because of the number of scientists and soldiers in their party who were somewhat anxious all the shaking might cause the gadget to explode en route, Kistiakowsky jumped into the cab of the truck alone and took it for a quick spin over the rough roads. For security reasons, the bomb was escorted by an entire entourage of guards, with military police cars in front and back. Every time they came to a town, they blared their sirens and flashed their lights, reportedly in an effort to fend off any drunk drivers, but this defeated the whole point of their secret nighttime expedition by virtually announcing their presence to the sleepy inhabitants as they barreled through.

By contrast, Bob Bacher had arranged for the plutonium core of the bomb to have an extremely quiet trip to Trinity. His contingent left Los Alamos at 3
P.M.
that Thursday, winding their way down the mountain and through Española and Santa Fe and then on to Albuquerque unnoticed in an ordinary government sedan, a carload of MPs leading the way. Phil Morrison, who accompanied him, was also bringing the initiator. He recalled that they drove no more than thirty miles an hour and for the whole trip down were “apprehensive about an automobile crash or some catastrophe of the sort that might make it very difficult to run the test.” They knew that only when the two hemispheres of plutonium were united could they achieve critical mass. Still, they took every conceivable precaution, packing the two halves of the nuclear core in specially designed cases, protecting them from the shock of impact, corrosion, over-heating, overcooling—anything they could think of that might affect their precious cargo as it made its way across the desert and, when the time came, across the ocean to the Pacific.

Early on Friday, the two parts of the bomb were delivered to the temporary “clean room” set up in the abandoned McDonald ranch house, which had been vacuumed and whose windows had been sealed with black electrical tape against the pervasive dust. That morning, the final assembly phase began, with eight scientists outfitted in white surgical coats bending over a makeshift laboratory table where the plutonium pieces had been arranged on sanitized brown paper. The initiator, Hans Bethe’s creation, was a spherical shell of beryllium containing polonium, which on implosion would mix and produce the triggering neutrons. Warm to the touch, it was very carefully placed inside the two halves of the plutonium core, the mating pieces of the globe fitting together like a particularly lethal puzzle. Oppenheimer hovered in the background next to Thomas Farrell, the boyish young brigadier general whom Groves had chosen to represent him at the assembly site because of his rule that both project leaders not be present in situations where there was “an element of danger.” Waiting on the dirt road outside stood four jeeps, their motors idling, just in case the core accidentally went critical.

By afternoon, the core was mounted in a cylindrical plug of uranium and ready to go. The scientists gingerly placed it on a small litter and carried it out to the backseat of the same sedan they had driven to the desert. They eased the car into gear and rolled toward the one-hundred-foot tower. At ground zero, at the base of the tower, was a tentlike enclosure covering Kistiakowsky’s partially assembled implosion device, a five-foot sphere complete save for the cylindrical plug containing the plutonium and the initiator. The plug was attached to a manually operated hoist and, while everyone held his breadth, gently lowered into the bowel of the high-explosive shell. The first attempt to insert the plug failed, inducing a horrifying moment of panic. A few people stepped out of the tent to steady their nerves, while Oppenheimer, Kistiakowsky, and Bacher tried to calmly assess what had gone wrong. Bacher quickly surmised that the sweltering heat inside the farmhouse, combined with the car ride, had raised the temperature of the plutonium core and caused it to expand, whereas deep down in the shell it was still very cold. With prolonged contact, however, the temperatures would equalize, and the minutely calibrated plug would probably fit. A few minutes later, the plug finally slid into place. With that crisis averted, the explosive blocks were packed in without further complication, and the test device was buttoned up for the night.

Early Saturday morning at Trinity brought a singularly peculiar sight. The tent was removed, and the physicists prepared to raise the bomb assembly to the top of the tower using a huge winch, which Groves had procured for the astronomical price of $20,000. But the scientists, novices when it came to large-scale construction, had been so worried by the possibility that the cable would snap and the five-ton device would fall that they arranged to take some highly unusual precautions. Standing by all around the base of the tower were large army trucks containing hundreds of mattresses, the great mountains of striped cotton ticking visible above the metal siding. After they had hesitantly wound the device about fifteen feet in the air, a contingent of GIs rushed in and stacked nearly twelve feet of bedding on the ground directly underneath it. Just in case Fat Man fell, it would have something soft to land on. The gadget was then safely hoisted onto the tower, brought to the corrugated-steel shack on the top of the platform, where the detonators were inserted, and hooked up to the firing console.