World War II: Spies and Scientists

World War II Reference Library. Editor: Barbara C Bigelow, et al., Volume 2: Almanac, UXL, 2000.

Acountry at war wants to find out how strong the enemy is, what its weaknesses are, and what its plans are. And each country does everything possible to keep this information secret. Gathering information, in all its forms, is called intelligence; preventing the enemy from learning information is called counterintelligence. Countries at war also try to develop technology and weapons that are better than those of the enemy. Scientists play a major role in developing new technology or enhancing existing equipment that will help win the war, creating anything from drugs to heal wounded soldiers to stronger or more accurate bombs to drop on the enemy.

Sneak Attacks

One of the most important secrets in any war setting is where and when an attack is coming. Countries in World War II used every way they could to protect this information. When the Japanese fleet sailed to attack Pearl Harbor in December 1941, its orders were hand-delivered by courier. (The Japanese attack on Pearl Harbor is described in Chapter 4.) At sea, the ships did not use their radios to communicate with one another or with Japan. This radio silence prevented the Americans from knowing where the Japanese ships were—or even that they had sailed. The fleet also used natural conditions to conceal its movements. It sailed across the Pacific on the edge of an advancing weather front. Heavy clouds and constant rain made it much less likely that the fleet would be seen by American reconnaissance planes sent ahead to gather intelligence.

The Germans also kept careful radio silence and used fog and the heavily wooded terrain of the Ardennes Forest to keep Allied planes from seeing their preparations for the Battle of the Bulge. (See Chapter 12.) Despite German precautions, however, there were strong hints that there might be a major attack in the Ardennes. For example, the Allies knew that the Germans were moving some tough armored (tank) divisions into the area. Unfortunately, the top American generals were convinced that the German army was then too weak to launch a major offensive and that even if one came, it would not be in the Ardennes. So they explained away the information they had learned. They came to the conclusion that the Germans were sending new divisions to the area to let them rest in a quiet section of the battlefront.

Decoys and Deceptions

Even better than concealing the location and timing of an attack is making the enemy think it is coming somewhere else. One famous example of this occurred before the Allied invasion of Sicily in July 1943 (described in Chapter 10). The Allies had just finished clearing North Africa of German and Italian troops. Nearby Sicily was the obvious next target, or so it seemed.

“The Man Who Never Was”

British intelligence officers in England found a man who had died of pneumonia—which can look as if the cause of death were drowning. They dressed the body in a British officer’s uniform, took it by submarine to the coast of Spain, and released it where they knew it would float to shore. It looked like the body of a soldier who had drowned after his plane had crashed into the sea.

Spain was officially neutral in the war, but it was unofficially pro-German. The body of the British “officer” attracted the attention of German agents in Spain—just as the British wanted. The officer carried various papers in his wallet and in the briefcase chained to his waist. These documents identified him as a captain in the British marines, an expert on landing craft on his way to North Africa to join the staff of the British commanding general there. He also carried various personal items that confirmed his identity. All of these were fake, part of the British plan.

Most important, he carried a top-secret personal letter from one British general to another. This letter made it clear that the next Allied invasion would not be in Sicily but in Greece and the island of Sardinia. The letter also said that the British should continue to try to make the Germans think Sicily was the target.

The letter included some negative comments about other top generals as well. That explained why it was being hand delivered, instead of being sent through official (and coded) radio messages. The Germans were not sure whether all this information was authentic. Being handed a personal letter from a top British general explaining invasion plans seemed too good to be true. Even so, probably on German leader Adolf Hitler’s personal orders, the Germans sent reinforcements to Greece and Sardinia. Because of “the man who never was” (as both the book and movie about this deception are titled), one of Germany’s best armored divisions and a mechanized infantry division were not in Sicily when the Allies attacked it.

Operation Fortitude

A much more considerable deception occurred in connection with the D-Day invasion of Normandy in June 1944. Code-named Operation Fortitude, it was by far the most successful counterintelligence operation conducted by any country in the war.

The Germans knew the invasion of Europe was coming soon. The most likely place for it was the area of northeastern France called the Pas de Calais. It is the closest part of Europe to England, and the Germans had placed many of their best troops nearby, armored divisions ready to rush to the coast and drive an invasion back into the sea.

The Allies developed an elaborate plan to convince the Germans that the invasion force would land at the Pas de Calais. And they wanted to keep the German generals guessing as to whether the real invasion were at Pas de Calais even after troops were already landing in Normandy on D-Day. If the German leaders believed that Normandy might be a decoy and that the real invasion would soon take place at Pas de Calais— they would be afraid to send their tanks and best troops to Normandy. If they could be fooled, even for a few days, the German tanks and reinforcements might arrive in Normandy too late to defeat the Allies.

A real commander and a cardboard army The Allies created a make-believe army, the First United States Army Group, known as FUSAG. FUSAG was commanded by a real American general, George S. Patton, whom the Germans knew as one of the best American tank commanders. Just as the Allies wanted, the Germans believed that Patton was a logical choice to command the ground troops in the invasion.

Patton had a headquarters, as did the various army divisions and army corps that were supposedly part of FUSAG. There were constant radio messages sent between them and between FUSAG and other Allied military commands. The Germans could not understand the encoded radio messages, but they could tell that there were a great many of them. The number of messages made the Germans believe that FUSAG must be a very large force.

FUSAG headquarters was in southeastern England, across from the Pas de Calais, and German planes photographed it from high above. The photographs showed tanks, trucks, jeeps, and tents for soldiers. German spies in England confirmed the evidence from the planes. But it was all fake.

The tents were empty, and the tanks were made of cardboard. The Allies purposely allowed the Germans to hear the radio messages and let the German planes fly over and escape back to German-held France. (Any German plane that came near the real bases was shot down.)

Using double-crossers The German “spies” in England were actually working for the Allies. Every one of them had been arrested long before, and only those who had agreed to work for the Allies had been released. The British called this the Double-Cross System. For years, they carefully allowed the spies to report certain information back to the Germans, to make the Germans believe the spies were still loyal to them. But the information, although accurate, was always unimportant or arrived too late to do the Germans any good. Now the spies sent false information to Germany, helping to convince the German high command that FUSAG was real, that it was the invasion army, and that therefore the invasion would come at the Pas de Calais.

The deception continued right up to D-Day itself. Out of 92 German radar stations on the coast, the Allies successfully jammed almost all of them by electronic interference. However, they purposely allowed the 18 radar installations around the Pas de Calais to keep operating. As the great invasion fleet approached the Normandy beaches, a much smaller number of Allied ships sailed toward the Pas de Calais. Each boat towed balloons behind it. From each balloon, specially shaped strips of aluminum dangled. Just as intended, the German radar at the Pas de Calais “saw” a huge invasion fleet approaching.

Operation Fortitude helped keep the German tanks far from Normandy until it was too late. Even as hundreds of thousands of American and British troops were already in Normandy, Hitler refused to allow the armored divisions from the Pas de Calais to go there. Instead, they waited for the real invasion.

Spies

One of the ways to learn about an enemy’s plans is from spies. But there are many dangers in relying on spies. As the British Double-Cross System showed, spies can be “turned,” sending false information supplied by the enemy. The Germans, as well as the Allies, succeeded in turning spies several times. One major spy network in the Netherlands sent the British a great deal of information that was in fact created by the Gestapo, the German secret police.

Equally important, even an honest spy rarely has a complete picture of what is really going on. He or she is privy to usually only a small piece of information, which in itself may be misleading.

There are two ways to use spies in determining the accuracy of information. One way is to employ spies who do have access to important military or political leaders in the enemy country. This is the image of the secret agents whom people have learned about from spy novels and movies. But these spies were very rare in World War II. A second way is to employ a large number of spies, each sending back small bits of information. When all the pieces are put together and analyzed, an accurate picture unfolds.

A Powerful Double Agent: Admiral Wilhelm Canaris

There was one source of information that might have changed not just a battle but even the war itself. At various times during the war, Allied intelligence agencies had secret contacts with Admiral Wilhelm Canaris, the head of German military intelligence, called the Abwehr. By the nature of his job, he knew almost all German military plans and secrets. Canaris, whom Germany eventually executed for his part in the plot to kill Hitler (described in Chapter 12), apparently quietly opposed Hitler’s war plans right from the beginning. But he was also playing complicated political games inside the German military. In fact, historians are still not sure about Canaris’s goals, or even about what he actually did or didn’t do.

Canaris and other Abwehr agents seem to have given away some—but certainly not all—military secrets for years. In fact, there was a ring of anti-Hitler spies inside the Abwehr. Abwehr agents—possibly with Canaris’s knowledge—apparently warned the Dutch about Germany’s plan to invade their country in 1940. The Dutch ignored this information because they had no reason to trust its source.

It is also possible that the Abwehr was the original source of the Oslo Report, a document given to the British in Norway in 1940. It was a list of all the secret weapons being developed by Germany. (German secret weapons are described later in this chapter.) Once again, the British didn’t believe this document at first, thinking it might be a bluff intended to frighten them.

Spy for the Soviets: Richard Sorge

Canaris was in a position to make a real difference in the war, but as far as is known, he never did. The spy who probably had the greatest effect was Richard Sorge. Sorge was a German journalist in Tokyo—but he was also a spy for the Soviet Union. He became a trusted friend of German diplomats in Japan and of important Japanese officials. Unknown to any of them, and like most Soviet spies in World War II, Sorge was a communist who was secretly loyal to the Soviet Union because it was the first communist country. (Communism is a political and economic system based on government control of the production and distribution of goods and the abolition of private ownership of factories, banks, and most other businesses.)

Sorge and his small ring, which included Japanese communists, passed a great deal of information to the Soviet Union. But he is best remembered for two reports, one that was not believed, and one that was. In the spring of 1941, Sorge warned that Germany was preparing to invade the Soviet Union. He even gave the exact date, June 22, on which the Germans would attack. But this information made no difference, despite many other indications that it was true. Joseph Stalin, the Soviet dictator, simply did not want to believe that Germany was planning a war against him.

A few months later, Sorge told the Soviets that Japan would not invade the Soviet Union, as the Soviets feared. Instead, Japan would attack the United States and Britain. This information, confirmed by Soviet observations of Japanese troop movements, was believed. It allowed the Soviet army to transfer a large number of troops from the border between the Soviet Union and Japanese-occupied northern China, where they had been stationed. These troops, including some of the best in the Soviet army, went west to fight the German invasion. It was a crucial moment in the war because the German army had almost reached Moscow, the Soviet capital. The reinforcements helped stop the German advance and then played a major role in the Soviet counterattack. (These events are described in Chapter 3.) By the time of the Soviet victory near Moscow, however, the Japanese secret police had arrested Sorge. After nearly three years as a prisoner, he was executed in July 1944.

The Networks

Unlike Canaris or Sorge, most spies are not in a position to learn top-level secrets. But spies who gather small pieces of information about the enemy can be very important if there are enough of them. The Allies had an enormous advantage in this kind of intelligence gathering. Throughout Europe, thousands of people were willing to risk their lives to defeat the Germans who occupied their countries. (An occupation is when one country stations military forces in another to control it.) They joined together secretly in resistance movements, groups opposing the occupation.

Resistance Movements Spy for Allies

Resistance movements engaged in a wide variety of anti-German activities, from secretly publishing newspapers to blowing up railroad lines. (See Chapter 6 for more information on resistance movements.) They also spied on the Germans and sent their information to the Allies.

Much espionage work involves gathering information that might seem unimportant but when collected and analyzed reveals a great deal. For example, a member of a resistance organization might note the insignia worn by German soldiers coming to the town cafe. The insignia would show which units were stationed in the area. If one unit left or a new armored division arrived, it was almost always known to local resistance groups, who sent the information to England by radio. To radio was extremely dangerous because the Germans had detecting devices to find radio transmitters. Radio sets were carefully hidden, often in suitcases, and sometimes moved from one attic hideout to another. They were taken out only for short transmissions. Sometimes information and agents got to England aboard a plane that landed at night in a field, guided by resistance flashlights.

Sometimes the information was very valuable. Members of the Polish resistance recovered key parts of a secret German V-1 flying bomb that crashed during tests and got them to England. Information from resistance networks also helped ensure the success of the Normandy invasion. (See Chapter 11.) The Germans created a system of fortifications, obstacles, and mines along the coast of Europe to protect against Allied invasion. It was called the Atlantic Wall. French resistance groups learned every detail about the construction in each area and passed this knowledge to Britain. These details helped the Allies choose where to land. In addition, the resistance built scale models of the landing beaches, showing the location of the German fortifications. With the help of these models, Allied troops could practice attacking German positions, knowing where the enemy troops were located, how well they were protected, and what kind of equipment they had.

British Spy Network: The SOE

In addition to the resistance groups that engaged in espionage, the Allies set up their own intelligence networks. In July 1940, less than a month after France surrendered to the Germans, Britain began creating an organization called the Special Operations Executive, known as the SOE. It was in charge of both intelligence activities and sabotage (destruction of military or industrial facilities) for Europe and had sections responsible for each occupied country. The SOE recruited agents from among the thousands of foreign refugees who had fled their homes and made their way to Britain and still wanted to fight the Germans. It also recruited English people who spoke other European languages.

Invisible ink and hand-to-hand combat In the English countryside, the SOE created training centers, usually in a large country house. There, the newly recruited agents were taught to be spies. They learned how to encode their messages to make them secure. They learned Morse code to transmit messages, how to assemble and operate their secret radio transmitters, even how to use invisible ink. Training sergeants from the British army gave them lessons in hand-to-hand combat and how to kill an enemy silently. Then the SOE sent them into Europe, by parachute or sometimes by submarine.

American Spy Network: The OSS

The American Office of Strategic Services (OSS) had the same mission as the British SOE: intelligence and sabatoge. The OSS was run by Colonel William J. Donovan, a millionaire lawyer who had gotten the nickname “Wild Bill” during his service in World War I. Sometimes OSS operations lived up to this nickname. OSS agents such as Allen Dulles (later the longtime director of the Central Intelligence Agency), working in neutral Switzerland, had important secret contacts with men such as Admiral Canaris in Germany. Later, OSS agents helped armed resistance groups fighting the Germans. But most of the spying networks in western Europe were already in existence when the OSS was created. Especially in France, the largest and most important country in the area, the spying networks reported to the British SOE.

Marie-Madeleine Fourcade and the Alliance

One of the key groups working with the SOE was called the Alliance. The Gestapo called it Noah’s Ark because each agent’s code name was the name of an animal. Its leader was a young woman named Marie-Madeleine Fourcade, code-named Hedgehog. The Alliance received most of its funds and equipment from the SOE and reported its intelligence findings to it, but its members and leaders were all French.

The Alliance organized a network of spies in every part of France. Its agents included people from all sections of French society. There were French military officers who were supposedly working for the pro-German government, naval engineers, and salesmen. One of the most valuable agents was a young woman whose job as a seamstress in the French port of Brest included sewing damaged life vests for the crews of German submarines. By listening to the crews’ conversations, she learned which submarines were leaving port and on exactly what date—which meant that British warships would often be waiting for them. Information on German submarine bases and other naval facilities was one of the network’s specialties.

Although France was the SOE’s most important area of operation, there were also 35 networks in Belgium with a total of 10,000 people, including about 300 who had parachuted in. Networks in the Netherlands, Belgium, and France cooperated in setting up escape routes for Allied air crews who had been shot down.

The Red Orchestra

The largest spy network, and one of the most successful, was probably the Red Orchestra. Many of its most important members already had experience in secret activity because they were communists, and communist parties had often been illegal in pre-war Europe. The Red Orchestra did not report to the British SOE but instead sent its information to the Soviet Union.

The Red Orchestra had agents in France, Belgium, and the Netherlands. But what made it unique was that it also had a substantial network in Germany itself. In some ways, the Red Orchestra resembled other resistance networks. It distributed anti-Nazi pamphlets and posters, helped fugitives escape from the Gestapo (the German secret police), and even engaged in small-scale sabotage of war industry. Amazingly, however, it did these things in Germany.

Much of the Red Orchestra’s work, however, and what it is mostly remembered for today, was in intelligence activities. It concentrated mostly on giving the Soviet Union an accurate, day-to-day picture of the German forces. Between 1940 and 1943, the members of the Red Orchestra sent about 1,500 radio messages back to the Soviet Union. For a time, one of its sources was an intelligence officer in the German air force. In August 1942, the Gestapo arrested about 100 Red Orchestra members and tortured them to make them reveal information about the network. Germany then tried and executed many of them, a result that was guaranteed by the fact that Hitler took a personal interest in the procedures.

Eavesdropping on the Enemy

The most important and dependable source of intelligence in World War II was not spies but the interception of secret messages sent by the enemy. This was true both in Europe and the Pacific.

Japan’s Codes Broken

In 1940, even before the United States went to war, American experts broke the code, called the Purple Code, used by the Japanese government to communicate with its ambassadors and other diplomats around the world. Japan never discovered that the code had been broken and continued to use the same code, which the Americans continued to intercept, until 1945. These diplomatic messages gave a good picture of Japanese intentions in general, though not of Japanese military or naval plans. However, the Allies learned German military secrets from these messages because Japanese diplomats in Germany used the Purple Code to send reports to the Japanese government, including information about new German weapons and how effective the Allied bombing of Germany was.

By the spring of 1942, the United States could also read many of the most important Japanese navy codes. Beginning a year later, the Americans also began to break the codes used by the Japanese army. The United States called the system of breaking and reading Japanese military and naval codes Magic.

Magic influenced the outcome of the war in the Pacific in both large and small ways. The Japanese probably lost hundreds of ships because Magic intercepts (intercepted and decoded messages) were used to send American submarines to sink them.

The most significant use was at the Battle of Midway in June 1942, considered the turning point of the Pacific war. (Midway is described in Chapter 4.) Partly because Magic revealed the Japanese attack plan, the outnumbered American aircraft carriers won a decisive victory.

In April 1943, Admiral Isoroku Yamamoto, Japan’s most prominent naval commander, who had planned the attack on Pearl Harbor, was flying to the island of Bougainville in the South Pacific. The Japanese transmitted, in code, the exact route and time of his flight. A squadron of American fighter planes, specially outfitted with extra gas tanks for this mission, waited for Yamamoto’s plane and shot it down, killing him.

Ultra: Breaking the German Code

The vast ocean distances of the Pacific meant that both the Americans and Japanese relied on radio messages, which can be intercepted by the enemy’s radios. In Europe, the Germans could communicate by telephone and telegraph (land lines), which at the time were more difficult to intercept than radio messages. The Germans could also use messengers traveling by train or car. Even in Europe, however, orders to ships or submarines had to be by radio. As the war continued, sabotage of land lines and the bombing of railroads increased German reliance on radio messages.

Unknown to the Germans, using land lines or messengers was the only sure way of keeping their communications secret. Germany developed its code long before the war and military intelligence agents from Poland, France, and Britain had been working to break the code since before the war. An anti-Nazi German helped the allies break the code by turning over key information to the French.

The organization that decoded, evaluated, and distributed German messages was called Ultra. Its headquarters at Bletchley Park in the English countryside was called the Government Code and Cipher School. The staff at Bletchley Park included mathematicians from nearby Oxford and Cambridge Universities. One of them, Max Norman, designed the world’s first electronic computer, which was built at Bletchley specifically to help break the German codes.

The Germans used an encoding machine called Enigma that looked like a typewriter. Using information from the intelligence agents, the code breakers at Bletchley reconstructed a version of an Enigma machine, but this alone did not break the German codes. Special gears inside the Enigma allowed trillions of possible code combinations, and the codebreakers at Bletchley had to figure out which combination was being used for each message. And they had to do it quickly enough for it to be useful. The person sending the message from the Enigma machine had to let the person receiving it know how to decode it, so at the start of each message was a key. The keys established a pattern that the mathematicians at Bletchly could use to break the coded messages.

For most of the war, the Allies could decode many German radio transmissions. Eventually, they could be decoded so rapidly that Allied generals knew their contents as quickly as the German generals to whom they were addressed. The Americans and British often knew exactly what the Germans would do. Probably the most important example was during the last stages of the Battle of Normandy, in August 1944. Hitler ordered a surprise counteroffensive centered on the town of Mortain and committed all available armored divisions to this attack. But the Allies knew about this plan and positioned their own armored divisions to stop it. The German defeat at Mortain opened the way for the Allied break-out from Normandy and across France to the German border.

The Germans did not know that any Enigma messages could be read, and the Allies took extraordinary precautions to prevent them from finding out. Sometimes the Allies did not act on secret information because that would have alerted the Germans that their code had been broken. When the British warned the Soviet Union that Germany was about to invade, they did not tell the Soviets that this information had come from reading top-secret German messages. Like Richard Sorge’s similar warning (described earlier in this chapter), it was not believed.

Science and Secret Weapons

Bletchley’s computer was only one example of the greatly increased role of science in World War II. Perhaps the most important scientific development was radar, originated by the British. Secret work on radar was conducted beginning in 1935, and the first radar station on the coast was ready two years later. By the time of the Battle of Britain in 1940, there was a chain of 50 radar stations operating on the coasts of England. These stations gave the British a vital early warning of the number, direction, speed, and altitude of the attacking German planes. This knowledge allowed the outnumbered British to send planes from other areas to defend that day’s targets.

But scientists everywhere were working on the same idea, and the Germans soon had radar too. Radar technology kept improving throughout the war. At first, radar required large sensing devices (dishes) mounted on towers. Eventually, instruments were made small enough to fit into planes, allowing bombers to hit targets they could not see and letting fighter planes find and attack bombers at night. Special British planes had radar that spotted submarines 30 miles away. Another development based on the same principle as radar was the proximity fuse for artillery shells. The fuse caused antiaircraft shells to explode when they came near their target, destroying planes even if they weren’t hit. The British were using these to shoot down V-1s in August 1944, but the Germans never developed this technology.

Hitler’s Secret Weapons: The V-1 and V-2

The V-1 was a pilotless jet plane that could travel a maximum of about 250 miles, reaching speeds of 375 miles an hour, about the same as the fastest regular fighter planes of that time. It made a buzzing sound, and Londoners named them buzz bombs. When the buzzing stopped, it meant the V-1 had run out of fuel—making it fall to earth and detonate the nearly one ton of explosives that it carried. The V-1 caused greater damage than regular bombs because the angle at which it fell caused more of the force of the explosion to remain near the surface instead of underground.

The first V-1s Germany launched against England on June 12, 1944, a few days after the Normandy invasion, catapulted from portable ramps on the coast of France. The V-1s were not accurate enough to be aimed against specific targets. Instead, their target was anywhere in the city of London.

A total of 35,000 V-1s were produced, and more than 9,000 were fired at London. About a third of these were defective and never reached their targets or were shot down by British fighter planes and antiaircraft guns. Because they still exploded when they hit the ground, it was paramount that they be destroyed over the countryside before they reached the city. Before long, the Allied armies in northern France pushed the Germans away from the coast and the V-1s could no longer reach London. About 10,000 were fired at the Belgian port of Antwerp after the Allies captured it in September 1944. Altogether about 2,500 V-1s exploded in London, the same number as in Antwerp.

The V-2 was another type of German bomb. It was a 50-foot-long rocket powered by liquid fuel that was launched straight up and then flew at more than 2,000 miles per hour. This is faster than the speed of sound, so people on the ground could not hear the missile coming before it landed. The lack of any warning made it especially frightening. The V-2 also caused many people to be blinded because shattered window glass flew into their eyes before they could raise their arms to protect their faces.

The Germans fired the first V-2s at England in early September 1944. Because their development had been so rushed, many were defective, with up to 25 percent crashing immediately after launch. More than half of the rest disintegrated as they came to earth, but the explosives they carried would still explode. Although some radio-controlled correction of its course was possible, the V-2 was hardly more accurate than the V-1.

About 3,200 V-2s were launched during the war, more than half at Antwerp. They killed a total of about 15,000 people, about 2,500 of them in London, and injured perhaps 50,000. The Allies finally captured the German’s last launching sites in March 1945.

Both the V-1 and V-2 caused extensive damage to homes and other buildings. But because of their lack of accuracy, they had very limited military value. As used in World War II, they were weapons meant to terrorize civilians.

Jet Planes

Jet engines allow planes to fly much faster and higher than propeller planes. The pilotless V-1 used a jet engine, and the German air force also developed jet-powered planes for combat. The first German jet had its test flight just before the war began, in 1939. But the project was not considered high priority, probably because Hitler and most German generals were convinced the war would be a short one and long-term projects would not be ready in time. Later, it seemed more important to devote Germany’s limited resources to producing more tanks and submarines.

In the summer of 1944, however, jet-powered German fighters began to appear in the air battles over France. By this time, the Allies had complete control of the skies, and each jet was vastly outnumbered by Allied planes. The Allies also attacked the jets on the ground. Jets require much longer run-ways, and so it was easy to find their bases. Germany also had a severe shortage of aviation fuel. In fact, half the 2,000 jets Germany built by the end of the war never flew because there was not enough fuel. The fuel shortage also made it impossible to properly train pilots to fly them. In any case, British and American jets were also beginning to fly and would soon have become available if needed to challenge the Germans.

The Atomic Bomb

The largest scientific project of World War II—and the most secret—was the building of the atomic bomb. It is also the military development that has had the greatest impact on the world since then. But the bomb played a small role in the war itself because it was completed only at the very end. By that time, Germany had surrendered, and the Allies dropped the bomb on an almost-defeated Japan. (The use of the atomic bomb against Japan is described in Chapter 15.) It is ironic that the bomb was used against Japan, since the main reason the Allies built the bomb was that they were afraid Germany would produce one first. Many of the scientists who built the bomb were refugees from Hitler’s Germany who hated and feared the Nazis. (See box on p. 366.) They also believed that Germany, with its outstanding scientists, would have a head start.

The German Bomb Project

By the beginning of World War II, every top physicist in the world knew the theory of atomic weapons. But no one was sure that a bomb could actually be built. And even if it were possible, the process might be so expensive and time-consuming that it was not worth trying. The German scientists who explored the possibility of building an atomic bomb— including Werner Heisenberg, one of the greatest physicists of the century—made some vital errors in their theoretical calculations. These errors made them think that building a bomb would be more difficult and expensive than it really was. Because of this, the Germans never considered the project a top priority. There was no single agency in charge to ensure that it got the people, equipment, and money it needed. When Germany surrendered in May 1945, its atomic weapons program was at about the same stage that the Allies had reached in 1940—before the American program had even started.

The Science Behind the Bomb

When a certain kind of uranium is bombarded with neutrons (one of the particles that make up the atom), its nucleus (center) splits in two, releasing energy. It also frees other neutrons, which in turn collide with nearby uranium atoms, causing them to split. If there is enough of this uranium “fuel,” the process continues until all the uranium atoms have been split, something that takes only a fraction of a second. The result is a nuclear chain reaction that releases previously unimaginable amounts of energy—energy that can take the form of an explosive blast.

The particular type of uranium needed, U-235, exists only in tiny quantities in uranium ore dug from the earth. Separating the U-235 from the rest of the uranium is a very complicated and expensive process. In fact, in 1940 no one was sure how to do it in large quantities. The German scientists miscalculated how much U-235 would be needed. They thought a chain reaction, and therefore a bomb, would require about two tons of U-235. This meant that building an atomic bomb, if it were possible at all, would take many years and be incredibly expensive. Since Germany’s political and military leaders all expected the war to be short, they concluded that even an all-out effort to build an atomic weapon would not succeed in time to make a difference.

The error the German team made was not a small one. At the beginning of the war, in April 1940, two refugees from Nazi Germany working at the University of Birmingham in England, Otto Frisch and Rudolf Peierls, were studying the same problem. They calculated that a much smaller amount of U-235 was needed for a chain reaction: not two tons, but less than one pound. Frisch and Peierls then sent a letter explaining that “a radioactive superbomb” could be produced to the British government’s leading scientific adviser. Although, like the Germans, the British first thought such a project would probably take too many resources, they appointed a committee of scientists to recommend action. The group studied the problem for more than a year and came to the conclusion that a bomb could be built in two years and that work should begin immediately. Late in 1941, Britain launched the Directorate of Tube Alloys, giving the project charged with building an atomic bomb a name that purposely made it sound as if it were studying new and better metals to make pipes.

The Manhattan Project

At first the British made greater progress than the United States on building an atom bomb and—although no one knew it—much greater progress than the Germans. But in June 1942, six months after the United States entered the war, President Franklin D. Roosevelt gave the go-ahead for a full-scale American atomic project. The Americans soon caught up with and then passed the British.

The organization that controlled all aspects of research, construction, and testing had the deceptive name of the Manhattan District of the Army Corps of Engineers, and became known as the Manhattan Project. The project cost $2.5 billion, an enormous amount at that time.

Eventually, 120,000 people were involved with the Manhattan Project. The Americans built secret factories in Oak Ridge, Tennessee, to work on separating U-235 from uranium. Since no one was sure which of three possible methods was the best way to do this, the project tried all three, despite the expense. In addition, another huge facility was built in Hanford, Washington, to produce plutonium, another element that scientists correctly thought could be used as fuel for an atomic bomb. In both places, workers and their families lived in newly built housing, surrounded by fences and armed guards to keep the work secret.

The heart of the Manhattan Project, however, was at Los Alamos, New Mexico. There were gathered 4,000 physicists, mathematicians, chemists, engineers, skilled metalworkers—experts in every aspect of the complex process of designing and building the new weapon. The head of the project was J. Robert Oppenheimer, himself a brilliant young physicist, who somehow managed to keep all the different personalities working together.

On July 16, 1945, in the desert near Alamogordo, New Mexico, the first atomic explosion in history sent a blinding light through the predawn darkness. As Oppenheimer watched the test, he thought of words from the Bhagavad-Gita, a Hindu holy book: “I am become Death, the destroyer of worlds.” Within a month, America dropped two atomic bombs on Japan, killing 120,000 people and obliterating the cities of Hiroshima and Nagasaki.