by Sam Kean
CHAPTER 22
Letters
After a year of chaperoning frat boys at Harvard, Samuel Goudsmit was finally doing something useful. In November 1941 a colleague down the road at the Massachusetts Institute of Technology had recruited him to work on radar there. As someone whose interests ranged far beyond physics, Goudsmit enjoyed the eclectic mix of people in his new lab. There were lawyers and soldiers and intelligence analysts running about, even a husband-and-wife team on loan from Disney to illustrate a book about radar—not for children, but for slow-witted generals. Best of all, Goudsmit felt he was really contributing to the war at last. He was feeling so confident, in fact, that he took a foolish gamble and nearly got himself arrested.
As so many scientific troubles did during the war, it all started with Werner Heisenberg. In October 1942, an exiled Austrian physicist in New York, Victor Weisskopf, received a letter from a colleague in Switzerland that mentioned two things. First, that Heisenberg would be giving a lecture in Zurich soon. Second, that Heisenberg had accepted a new job at the Kaiser Wilhelm Institute in Berlin. This was mostly just chitchat, but as the politically savvy Weisskopf read and reread the letter, his face creased with worry. KWI was a state-run (i.e., Nazi-run) entity with a strong nuclear physics program. Rumors had already been swirling about Heisenberg’s “atomic explosion” in Leipzig, as well as the German interest in heavy water. Heisenberg’s move to KWI, then, could mean only one thing: Germany was ratcheting up its nuclear bomb program.
Just before Halloween, Weisskopf showed the letter to another émigré who worked at MIT. He agreed that it sounded dire. Unsure what to do, they grabbed a bottle of liquor and decided to drink things through. As the fog of booze saturated their brains, a plan took shape. The letter had mentioned Heisenberg giving a lecture in Zurich in early December. Switzerland was a neutral country, offering free passage to both Axis and Allied citizens. Perhaps they could send a scientist there to question Heisenberg—feel him out about German progress. Why not?
As they poured another round the idea got a little bolder. Instead of just sounding Heisenberg out, what if they could disrupt the German project somehow? Maybe by delaying Heisenberg’s return to Germany. Or heck, maybe they could delay him permanently—detain him and prevent him from returning at all. It was a stupid idea, of course—far too risky. But after another sip or two, it didn’t seem so ridiculous anymore. Why couldn’t they detain him? This was war, after all. Anything goes. If they planned properly, Heisenberg wouldn’t be in any real danger, and getting him away from Germany would derail the entire Nazi bomb project. The more sloshed the two got, the more clever the idea seemed, and the very next day Weisskopf shook off whatever hangover he had and wrote a letter to Robert Oppenheimer.
The letter relayed the gossip about Heisenberg’s new job and what that portended, then mentioned his upcoming lecture in Zurich. With startling bluntness, Weisskopf added, “By far the best thing to do… would be to organize a kidnapping.” The Germans wouldn’t hesitate to kidnap you, he pointed out to Oppenheimer. And while the plan certainly carried risks—they would be violating the neutrality of Switzerland, and whoever approached Heisenberg might be seized as a spy if things went south—those dangers seemed negligible weighed against the possibility of a Nazi atomic bomb. Despite the risk of capture and torture, Weisskopf volunteered to go to Zurich himself. “It is evident,” he concluded, as if this were a simple mathematical proof, “that the kidnapping is by far the most effective and safest[!] thing to do.”
By this time Oppenheimer was running the Los Alamos weapons lab and had no time for harebrained nonsense. He’d in fact already heard the news about Heisenberg through other channels, and his response to Weisskopf was filled with bland bureaucratic assurances about how the “proper authorities” would be notified. In what seemed like a polite brush-off, he added, “I doubt whether you will hear further of the matter.”
In private, though, Oppenheimer thought the kidnapping idea wasn’t half bad, and he forwarded it to the head of wartime scientific research, Vannevar Bush. In passing the proposal along, Oppenheimer noted that he wasn’t necessarily endorsing it, and he pointed out that Weisskopf would obviously be in over his head; they’d need a professional spook. Still, the visit to Zurich “would seem to afford us an unusual opportunity,” he wrote.
Bush in turn put Oppenheimer off with more blandishments. But he secretly liked the idea, too, as did the military honchos he mentioned it to. Ultimately, those officials vetoed the plan—not because it was dangerous and illegal, but because of game theory considerations. If we contact Heisenberg, they reasoned, the Nazis will know that we know about their atomic bomb program. This would in turn imply that we have a similar program, which would put us at risk. What’s more, the Nazis would redouble their efforts, and since we’re already lagging behind, that doesn’t seem wise. Incredibly, though, no one dismissed the idea outright, and the plan to shanghai a Nobel Prize–winning physicist continued to percolate in their minds.
Not that Victor Weisskopf knew any of this. For security reasons the people making such decisions never deigned to explain their reasoning to a peon like him. Beyond Oppenheimer’s letter he heard nothing back about his proposal, and after a week passed, he grew fretful. The lecture in Zurich was coming up soon—days were ticking off the calendar—and bureaucratic inaction seemed likely to ruin this opportunity.
Unable to sit still, Weisskopf and his drinking buddy decided that the British, who had the most to lose from an atomic Hitler, might be more open to their scheme. So they turned to their fellow émigré Samuel Goudsmit, who knew a few Brits working on radar at MIT. Goudsmit thought that kidnapping his old friend Werner was a smashing idea. His British contacts gave him a name to write to and encouraged him to slip the phrase “tube alloys” into the letter, that being the British code word for atomic bombs. Goudsmit did so and rushed to the mailbox on November 7, convinced that the letter would spur people into action.
It did—but mostly on this side of the Atlantic. Seeing the phrase “tube alloys” panicked British officials. How had this random physicist learned their most secret code word? They alerted Vannevar Bush, who opened an investigation into the breach. Humorless intelligence agents swarmed Goudsmit and demanded to know where he’d heard the term. Even more suspicious, Goudsmit had mentioned in the letter that he occasionally came across other tidbits of intel. Would the British like to hear those as well? You can imagine what the American agents thought of that. Goudsmit sputtered out an explanation and apologized for his clumsiness. More hard questions followed, and only begrudgingly did the agents clear him. He walked away from the incident chagrined, and with a clear understanding of his place within the wartime scientific hierarchy—at the bottom.
And yet, similar to Boris Pash, this brush with the clandestine side of science intrigued Goudsmit. He’d always adored detective novels and fancied himself an amateur sleuth. (When thieves had stolen equipment from his lab in Ann Arbor, he’d pulled out a fingerprinting kit and dusted for clues himself.) The idea of plotting war stratagems excited him even more. So despite his dressing-down, Goudsmit wrote another letter to intelligence officials offering his services. He pointed out that he spoke several languages, a useful asset abroad, and that he knew scientists in Italy, Holland, Belgium, and France. “I think there are even some German physicists who still believe I am their friend,” he added. The tone of the letter, frankly, was a tad pathetic. Please keep me in mind—I’ll do anything! And perhaps not surprisingly, no one bothered answering him. After his bungling attempt to arrange the kidnapping, it seemed that the intelligence community wanted nothing to do with Samuel Goudsmit.
Another letter soon banished his fantasies about espionage anyway. In the summer of 1942 the Reich had started deporting Jews from the Netherlands, and all communication between Goudsmit and his parents ceased. For months he’d been writing to friends in Holland, begging for help in tracking them down. This included Dirk Coster, the physicis
t who’d helped Lise Meitner escape Berlin.
Coster then turned around and, in late 1942 or early 1943 (the dates are uncertain), asked the most powerful German citizen he knew for help on Goudsmit’s behalf—Werner Heisenberg. After all, Coster reasoned, weren’t Goudsmit and Heisenberg friends? Hadn’t Heisenberg dined at the Goudsmits’ home? Ironically, then, the man Goudsmit had been plotting to kidnap was now, unbeknownst to him, the best hope to save his parents.
Meanwhile, in March 1943, Isaac and Marianne finally got a letter through to their son. Seeing their names on the envelope must have brought a surge of hope to Goudsmit—followed by despair, when he noticed the postmark. He had no idea how long the letter had been delayed in transit, nor how exactly it had reached him—a merciful German soldier? The Dutch underground? It had been routed through Portugal, he saw, but the original postmark was from a city called Theresienstadt in the former Czechoslovakia. It stood right next to a massive concentration camp.
CHAPTER 23
Operation Freshman
Winston Churchill once called heavy water a “sinister term, eerie, unnatural, which began to creep into our secret papers” in 1940 and 1941. Perhaps in deference to this squeamishness, British officials began referring to D2O as “Juice” instead. And as spies confirmed that the Germans were buying up every ounce of Juice they could find, intelligence agents began arguing over what to do about it.
Some advocated doing nothing, citing the same game-theory considerations that had recommended against kidnapping Werner Heisenberg. Yes, the Allies could no doubt disrupt German access to heavy water, perhaps by damaging the Vemork plant in Norway. But that would tip the Nazis off to Allied interest in this eerie, unnatural liquid. The Nazis would then conclude that the Allies were also working on a bomb, which would spur them to work even harder on theirs.
A dissenting group argued that action was imperative, especially given the Nazis’ head start. They wanted to bomb Vemork immediately. Norwegian agents, however, recommended against this approach. The mountainous terrain and unpredictable weather near Vemork would make bombing runs tricky. The cells that produced heavy water were located in the basement of the plant anyway, which made them difficult to destroy with bombs. And Vemork did more than produce heavy water: it supplied power and fertilizer for the region, and both of those operations would suffer far more damage in any raid.
In the end, the British settled on a third, riskier option: sending a team of commandos into Norway to infiltrate Vemork and sabotage the heavy-water cells. Responsibility for this mission fell to an agency called the Special Operations Executive, known informally as the Ministry of Ungentlemanly Warfare. Their job, as one historian put it, was to “singe Hitler’s mustache” by carrying out sabotage throughout Europe, and nothing would burn the Führer more than taking out Vemork—“the first attempt in history to strike a blow against atomic weapons.”
To disable Vemork, the Ungentlemen first had to understand how heavy-water production worked there. It started on the fifth floor of the hydrolysis building, where local river water was pumped in through pipes and collected in vats. An electric current then zapped the H2O and split off the hydrogen for use in fertilizer. Heavy water was a side effect of this process. Molecules of heavy water break down less easily than molecules of regular water, so if you zap a tank of water long enough, the leftover liquid contains a higher percentage of heavy water than before. You can now run this slightly enriched water through another zapping tank and enrich it further. After six such stages, running from the fifth floor to the first, Vemork could increase the concentration of D2O from 0.000002 percent to 13.5 percent.
To raise the percentage higher still, Vemork employed three more stages of filtration cells. These cells were engineering marvels, a warren of pipes, condensers, seals, valves, and asbestos diaphragms, with all sorts of feedback loops to goose production even more. They were complicated as heck and incredibly wasteful: for every 100,000 gallons of river water that Vemork consumed, just one gallon of heavy water dribbled out at the far end. But that gallon was 99.5% pure reactor Juice.
The question for the Ungentlemen was how to sabotage this process. It turned out that the head engineer at Vemork—who knew what the Nazis used heavy water for—had already been sabotaging things himself, by pouring castor oil into the production lines. This caused the water to foam up and disrupted its flow through the filtration cells, leading to backups and delays. The engineer had helped build the plant years earlier, and it broke his heart to foul up his own machinery, but he felt he had no choice. The British cheered the engineer’s cleverness—imagine stopping an atomic bomb with veg oil!—but he couldn’t disrupt things often or he risked being caught and shot. Such measures were only temporary anyway: after a little cleaning, production started up again. The British needed something more permanent, and violent. The last stage of processing involved filtering the Juice through eighteen ultraprecision cells in the basement of the plant. The British therefore decided to send commandos in to blow those cells to smithereens. They called the mission Operation Freshman.
With that plan in mind the British began selecting saboteurs. A few Norwegian expats advising the British government suggested sending in a crew of eight soldiers who’d grown up near Vemork; they were expert skiers and knew the terrain well. The British overruled them. Norwegian troops had no experience with sabotage or clandestine warfare, and on a precision mission like this, familiarity with explosives trumped familiarity with terrain. Rather than skiing in, the commandos could approach on foot instead, or on special folding bicycles. Eight soldiers seemed too few anyway, leaving no margin for error. The British thought thirty sounded more like the thing, and they drew them exclusively from the ranks of their own Ungentlemanly troops.
The thirty commandos trained on an estate outside of Cambridge. To mimic the approach to the plant, they practiced walking over tall grass in snowshoes, that being the closest approximation to snow they could find. (To conceal the reason for all this tramping about, their supervisors spread a story about training for an endurance competition against the Yanks, to win the coveted, and fictitious, Washington Cup.) To practice the attack itself, carpenters constructed an inch-by-inch replica of the plant’s basement using microfilmed blueprints smuggled out of Vemork in toothpaste tubes. The model was accurate down to the lock on each door, which the commandos learned to pick with the help of a master thief furloughed from a local prison. The soldiers drilled endlessly on navigating the mockup’s passages and laying the explosives just so, until they could complete the task in pitch blackness. Someone then came up with a felicitous final touch. After the commandos had destroyed the cells and escaped Vemork, the Nazis would of course pursue them. So at an easily discoverable spot the raiders would drop a map (drawn on a silk pocket handkerchief) with Vemork circled in blue and a false escape route plotted to western Norway. Meanwhile, the troops would be hightailing it a hundred miles east, to neutral Sweden.
As a concession to the Norwegians, the British recruited four Norse soldiers as an advanced reconnaissance team. These four, all drawn from central Norway, would parachute in a month ahead of time to prepare a landing strip, scout Vemork’s defenses, and escort the British commandos there for the attack. This prep work was essential because the area around Vemork was rugged beyond belief, a 3,500-square-mile plateau populated mostly by reindeer and swept by gusts of wind strong enough to knock grown men on their keisters. One historian described it as “one of the most godforsaken places on earth—the largest, loneliest mountain range in northern Europe.” Locals said the cold descended so quickly at night sometimes that flames froze in place. Even the plateau’s name, Hardanger, looked scary to English speakers, a seeming portmanteau of hard and danger.
For maximum secrecy, parachute drops took place only at night, and for maximum visibility, night drops took place only around full moons. By the mid-October moon, the advance team of four Norwegians—code-named Grouse—was ready to deploy. In cooperatio
n with British intelligence, the BBC altered its usual broadcast on October 18. Instead of saying, “This is the news from London,” the announcer began, “This is the latest news from London.” This one word alerted undercover agents near Vemork that the commandos would make the drop that night.
The Grouse team had to parachute down onto a scary, unforgiving landscape studded with boulders and crisscrossed by gorges you could disappear into and never be heard from again. The terrain compounded the danger, since British pilots were used to navigating by rivers and roads, whereas Hardanger offered only a confusing mess of black-and-white “tiger stripes” of rock and snow, all of which looked identical. Sure enough, although all four Grouse men landed safely, they were dumped thirty miles from their rendezvous point, with their equipment strewn all over kingdom come. They wasted two days tracking it all down, and as soon as they had, the Hardanger plateau clobbered them with a blizzard.
After that cleared, they began dragging their hundreds of pounds of food and equipment toward Vemork, a job made slightly easier when one of them discovered an old sled half buried in the snow. (Miraculously, he recognized it as his old childhood sled; two years earlier he’d loaned it to Norwegian resistance fighters, who’d apparently abandoned it.) But even the sled didn’t help much: the landscape was uneven, with snow reaching past the soldiers’ knees, and the wind and elevation made breathing difficult. After fifteen days of toil they finally arrived in the vicinity of Vemork, and broke into a log cabin to rest. Many such cabins dotted the plateau, but they were mainly for summer use, with thin walls and cracks that the snow whistled right through.