by Sam Kean
After scouting Vemork, the Grouse team tried establishing radio contact with London, a job that, given the weather, proved virtually impossible. Their batteries had frozen solid, and their antenna kept snapping in the wind; they had to jerry-rig something from ski poles and abandoned fishing rods. When they did finally reach London, they had nothing but bad news to report. Since taking over Vemork, the Germans had planted land mines, ringed the place with barbed wire, and emplaced several machine guns. Casualties seemed likely.
Nevertheless, plans went forward. On the afternoon of November 19, the Grouse radio operator sent a brief weather report indicating clear skies. London responded with the seeming non sequitur “Girl.” The operator’s heart no doubt began racing; Operation Freshman would begin that night.
Rather than parachute thirty troops onto boulder-strewn terrain and risk broken ankles, the British opted to deploy them with gliders, an idea they stole from the Nazis. Because gliders lacked engines, they couldn’t take off or fly on their own. A prop plane would tow them to the drop site instead using a 350-foot rope that was severed in midair. At this point the sixty-five-foot gliders would coast to the ground in silence, which masked their approach. But if you’re picturing a calm, controlled descent, think again. The gliders were made of plywood and weren’t exactly renowned for aerodynamic stability: to prevent people from slipping, the fuselage had a corrugated-iron floor specially designed to drain off vomit. And while German gliders had deployed troops with great success on the soft plains of Belgium, the hard danger of the Hardanger plateau offered far more opportunities for things to go awry.
Throughout November 19, the Grouse team sent periodic reports to London on the local wind speed and visibility, but by the time the British decoded these messages, fickle clouds and cold fronts had remixed the weather there. Feeling antsy, the British gave the go-ahead anyway, and the first plane-and-glider combo lifted off from northwest Scotland at 6:45 p.m., with the second following fifteen minutes later. Almost immediately winds began to buffet them, and by the time they reached the coast of Norway a storm was threatening to erupt. One observer later described the weather as “sticky with cloud.”
Down on the ground, the Grouse team prepared the landing site, arranging several red-beamed flashlights in an L shape and firing up a radio beacon (called Eureka) for the planes to home in on. Not long afterward they heard the drone of motors through the clouds. After a cruel month alone on the plateau, their spirits leapt—“Here they come!” one cried. “Up with the lights!” They began blinking the red beams on and off, their eyes straining for a glimpse of the plane above.
Then the drone faded—the plane was sailing past them. The men frowned, but weren’t overly worried. Perhaps the pilot just wanted to take a different approach; a second plane should be coming along anyway. Sure enough, the drone returned a few minutes later, and they resumed blinking the flashlights—only to hear the noise melt away again. When this happened a third time, the Grouse boys swallowed hard.
Finally, after more near misses, the noise faded one last time and never returned. At midnight the Grouse team trudged back to their flimsy cabin and radioed London, desperate to know what had happened. They soon regretted asking.
Up in the air, the pilots were lost. The receivers for the Eureka beacon had failed in both planes, and even when the sheets of clouds broke up a bit, giving them a chance to scan for the red L, they saw nothing but tiger stripes below. Twenty minutes passed, then an hour, then two, as the planes and gliders circled and recircled the plateau.
Eventually the pilots risked running out of fuel and had to turn back—at which point everything went to hell. Ice had been accumulating all night on the towlines holding each glider, and the ropes began to strain under the excess weight. One finally snapped as they neared the Norwegian coast, and the towing crew could only whip their heads around in horror as the glider began plummeting. It torqued into a spin at 200 miles an hour and disappeared into the clouds. The plane circled and searched to no avail, and when it finally returned in England at 3 a.m., the crew reported the glider lost at sea.
The towline of the second plane snapped as well, this time over land. Hoping to fix the glider’s position, this crew began circling the area, straining for a glimpse. Unfortunately, the pilot pushed things too hard in the heavy cloud cover and clipped the side of a mountain. The plane went tumbling down the slope and exploded after a few rolls, killing everyone aboard.
Its glider, meanwhile, crash-landed. Of the seventeen people aboard, three died instantly and six sustained critical injuries. After clearing everyone out of the wreckage, the commanding officer sent two men who could still walk to a local farmhouse to determine their whereabouts; perhaps they could still make a break for Sweden. Alas, the farmer told the soldiers they were four hundred miles from the border. He then added that he would have to alert the local Nazi command to their presence: the Germans were bound to hear about the crash, and he’d be shot as a traitor if he stayed silent. The soldiers returned to the crash site and informed their officer. He thought his men could probably fight off the first Nazi patrol, but more Germans would inevitably follow, and several troops needed medical care anyway. So when the Nazis arrived, the survivors surrendered. While they were being driven away in trucks, one captive playfully flashed a V-sign to the Norwegians who had gathered to watch.
What happened next came out only years later, during a trial for wartime atrocities, and because of contradictory testimony the truth remains somewhat obscure. Apparently the Nazi military commander of Norway had his men question the British about their mission, but they refused to say anything more than their name, rank, and serial number. The commander now faced a dilemma. In October 1942, Hitler had issued a secret Führerbefehl (Führer command) to shoot all foreign saboteurs on sight; the Germans privately called them “pirates.” And given the explosives discovered in the glider, these men were clearly saboteurs. But they were also wearing army uniforms. This technically made them prisoners of war, and the commander later claimed that every fiber of his being resisted the idea of executing them.
After wrestling with his conscience, the commander called up the field marshal of the Nazi armed forces, Wilhelm Keitel. (In a bizarre coincidence, Keitel was the uncle of Robert Oppenheimer’s wife Kitty, making him related to Oppenheimer by marriage.) Must we shoot them? the commander asked. Keitel gave a vague answer but didn’t contradict the Führer’s orders. Still unable to decide, the commander played Pontius Pilate, washing his hands of the matter and turning the commandos over to the Gestapo, who had fewer scruples about men in uniform.
After briefly imprisoning the fourteen men, the Gestapo rounded them up and herded them into a mountain valley. There, guards grabbed one man and frog-marched him toward a concrete ammunition shed. As soon as he was out of sight, the valley exploded with gunfire. The remaining thirteen men, still assuming that their uniforms would protect them, looked around in bewilderment. What are they shooting at? The guards returned for another man, and a minute later gunshots rocked the valley again. All fourteen were eventually marched off to the shed, where a firing squad awaited. Upon arrival, each commando was ordered to remove his army jacket, to preserve the fiction that the Germans weren’t shooting prisoners of war. Some refused and were shot anyway. One held up pictures of his wife and children, begging for his life; the reply was a barrage of bullets. One man was too injured to stand, so they propped him against a rock before taking aim. After each man fell, the commanding officer walked up and shot him in the head. All fourteen bodies were then tossed into a ditch.
When word of the atrocity reached Berlin, officials were furious. Not because it violated every international standard of humane warfare dating back several centuries. No, they bemoaned the lost intelligence. (Interrogate first, then shoot, you imbeciles.) Now the Gestapo would never know the saboteurs’ target.
Luckily for the Gestapo, it soon got a second chance.
Despite what the crew returning t
o England had said, the other glider hadn’t crashed into the sea. It landed short, splitting in half and killing six men on impact. Four others were critically injured, with fractured skulls and shattered limbs; two of them ended up frozen to the ground by their own blood. Here too the commanding officer judged the situation hopeless and surrendered to local Nazi patrols.
At least the men executed by firing squad had died quickly. Not so with this group. The German officer in charge—known as the Red Devil—hustled away the four critically injured soldiers and ordered a doctor to snuff them out with morphine injections. One died straightaway, but when the other three realized what was happening—the doctor had lied and told them they were receiving booster shots for typhus—they tried to resist. Big mistake. This enraged the Red Devil, who strangled one soldier with a belt. The doctor, wanting to be merciful, tried injecting air into the veins of a second, to kill him with an embolism. It didn’t work, so the Red Devil smashed the man’s Adam’s apple with his boot. The last British soldier was pushed down a flight of stairs and shot in the back. The Germans then dumped all four bodies into the sea.
The five uninjured soldiers ended up in Oslo for interrogation. These men also refused to say much, so the Nazis bound their hands in barbed wire, blindfolded them, and ordered them into a truck, supposedly for transport to a POW camp. After driving several hours, the truck stopped and the blindfolded soldiers stumbled out, their wrists no doubt shredded. Suddenly someone yelled “Achtung!” A blast of rifle fire, and all five men slumped to the ground. They were discovered after the war in a pit, still wearing their uniforms.
The only consolation the British could take from Operation Freshman was that none of the commandos had revealed the mission’s goal. But in the end, all their bravery in staying silent went for naught. In digging through the wreckage of one glider, the Nazis discovered a map on a silk handkerchief. The commandos had intended it as a red herring, to fool the Nazis into thinking they’d flee west instead of east. But the Germans ignored the supposed escape route and zeroed in on the site circled in blue—the Vemork heavy-water plant. They now knew the saboteurs’ target.
Freshman was a disaster on every level. Thirty top British commandos died. The map betrayed their target to the Germans, who then reinforced the defenses at Vemork (more barbed wire, more land mines, more guns). Worst of all, the Allies had tipped their hand about their interest in nuclear fission. They might as well have sent Hitler a postcard about Los Alamos.
Still, if Freshman left most people in despair, it steeled others. The Norwegian expats who’d been advising British intelligence had always hated Freshman: it was unwieldy, and involved troops unfamiliar with the terrain. (Who the hell ever dreamed that folding bicycles would work there?) Within a day of hearing about the disaster, two Norwegian officers began sketching out an even more audacious plan, called Operation Gunnerside. They were confident that they knew better than the British how to cripple Vemork.
CHAPTER 24
The Italian Navigator
After the lovelorn Walther Bothe bungled his graphite experiments, the Nazi atomic bomb project focused on using heavy water to study nuclear reactions. The American project, meanwhile, had always considered graphite the superior option, and their confidence in this carbon compound paid off handsomely in December 1942.
The Americans called their first nuclear reactor a “pile,” and for once this wasn’t an empty code name. It really was just a huge pile of graphite, 771,000 pounds of slippery black bricks stacked on the floor of an unused squash court at the University of Chicago. It took technicians seventeen days of around-the-clock labor to arrange them all, and the end result was an egg-shaped mound twenty-five feet wide and two stories tall. Although the court was unheated, the men building the structure worked up a good sweat, and many stripped off their shirts to stay cool—to their immediate regret. With all the graphite dust in the air, “We found out how coal miners feel,” remembered one. “We looked as if we were made up for a minstrel show. One shower would remove only the surface graphite dust. About a half hour after the first shower the dust in the pores in your skin would start oozing.”
The outermost bricks in the pile were solid hunks of graphite, but most bricks toward the center had holes drilled into them, which were filled with five-pound slugs of uranium. Each of the 18,000 slugs was capable of firing off neutrons in any direction. These neutrons slowed down when they entered the surrounding graphite, and the reduced speed allowed fission to take place when another slug of uranium absorbed them a fraction of a second later. You can think about the slugs as nuclear raisins suspended in a loaf of graphite, with each little bit of fruit contributing to the overall chain reaction.
Once the graphite and uranium were stacked in place, the pile would have gone critical by itself if not for a third component, cadmium. Cadmium is a particle sponge, gobbling up neutrons by the billions. So during the pile’s construction, workers occasionally left horizontal shafts between the graphite bricks, into which they slid thin wooden beams with cadmium slabs affixed to them. These were padlocked into place to prevent the pile from going critical prematurely.
Everything finally came together on December 2, 1942, one of those Chicago days when it’s so cold it hurts to breathe. The United States had been at war for a year at that point, largely in North Africa and on islands like Guadalcanal in the South Pacific. That very morning, the State Department announced that two million Jews had already died in Europe.
Forty-two people packed into the squash court that afternoon wearing hats, scarves, and gloves; most stood on a balcony overlooking the pile, but several technicians puttered about on the floor below. One of the men down there held an axe. They called him the SCRAM (safety control-rod axe man), and his job was to prevent this first nuclear chain reaction in history from deteriorating into the first nuclear meltdown in history. If the atomic pile got out of hand, he’d swing the axe down executioner-style and chop a nearby rope. This would release a Damoclean rod of cadmium hanging from the ceiling, which would plunge down a hole into the heart of the pile and kill the nuclear reaction. Should the SCRAM fail, another trio of scientists—jokingly called the “suicide squad”—stood ready on the balcony with buckets of cadmium-laced water, which they planned to hurl like slop onto the pile as a last resort. Both safety measures were crude, but then again, so was everything about the pile.
The critical experiments started around 2 p.m. Enrico Fermi, the Italian physicist who’d once sprinted through the halls of his institute in Rome, was in charge. He ordered the padlocked cadmium rods removed one by one while a radiation detector clicked away nearby. At each step Fermi made a few calculations with his slide rule and checked the readings on some instruments. (He’d been reading Winnie-the-Pooh to boost his language skills, and named each instrument after a different character: Pooh, Roo, Tigger.) Ultimately, he was trying to determine what’s called the “k factor.” The k factor governs whether a chain reaction fizzles or goes critical. Each time a uranium atom fissions, it releases neutrons. Sometimes those neutrons fly off and cause more fissions, sometimes not. The k factor measures how often on average they succeed. So if it takes four uranium fissions to produce one additional split, then k = ¼, or 0.25. If it takes just two fissions to produce an additional split, then k = ½, or 0.5. The key threshold is k = 1. After this point each split produces more than one new fission, and the reaction becomes self-sustaining.
With all but one cadmium rod removed, k had inched to within striking distance of 1. But rather than yank the last rod out and vault to criticality, Fermi milked things a bit. He ordered it withdrawn six inches. Then he checked Roo and Tigger, did a little calculation, and nodded. Getting warm. The rod was withdrawn six more inches, and Fermi did another calculation. Really close now—try six more. All the while, the axe man and the suicide squad stood at their posts, their fingers itchy. The radioactivity detector was meanwhile click-click-clicking more frantically with each step, eventually buzzing so
fast that, by some accounts, it sounded like “a burring drill.” Fermi continued to calculate. Six more inches, please.
Finally, at 3:53 p.m., Fermi looked up and grinned. K has reached 1.0006, he announced. It must have been an odd moment. The pile didn’t shudder or change visibly; it certainly didn’t start glowing or anything. Yet the graphite in Fermi’s pencil had just proved that the graphite in Fermi’s pile had crossed a new threshold in history—they were standing next to the world’s first nuclear reactor. A bomb was still a long way off: among other things, bombs require either enriched uranium-235 or plutonium. But Fermi had just narrowed the gap considerably.
There was no point in going further that day, so his assistants slotted the cadmium rods back in and let everything cool down. To celebrate, the assembled scientists broke out some Chianti and sipped from paper cups. The bottle had the traditional straw jacket on it, so they passed it around and everyone signed it.
Soon afterward the top Manhattan Project official in Chicago phoned another top official in Washington. “Jim, you’ll be interested to know,” he said, “that the Italian navigator has just landed in the New World.”
The other official perked up when he heard the code. “Is that so? Were the natives friendly?”
“Everyone landed safe and happy.”
The success of Fermi’s pile kicked the Manhattan Project into high gear. Now that self-sustaining chain reactions were possible, General Leslie Groves could start building industrial plants to enrich uranium in earnest. With a working pile, scientists could start breeding plutonium as well. Both developments gave Manhattan Project officials confidence.
On the other hand, Fermi’s success also revved up the fear of a Nazi nuclear bomb. Because if a motley crew of Americans could build a reactor, surely geniuses like Heisenberg and Hahn already had. In fact, within days of December 2, one Manhattan Project physicist—a future Nobel Prize winner, no dummy—grabbed some chalk in his office and “proved” on a blackboard that, given the rate of American progress, the Nazis would have the Bomb no later than December 1944, probably sooner. No one had any reason to doubt him.