Science and technology in the United States

Science and technology in the United States
African-American contributions
Discoveries
NASA spin-off technologies
Native American contributions
Puerto Rican scientists and inventors
Technological and industrial history
Inventions by date
(before 1890)
(1890–1945)
(1946–1991)
(after 1991)

The United States came into being around the Age of Enlightenment (circa 1680 to 1800), a period in which writers and thinkers rejected the superstitions of the past. Instead, they emphasized the powers of reason and unbiased inquiry, especially inquiry into the workings of the natural world. Enlightenment philosophers envisioned a "republic of science," where ideas would be exchanged freely and useful knowledge would improve the lot of all citizens.
From its emergence as an independent nation, the United States has encouraged science and invention. It has done this by promoting a free flow of ideas, by encouraging the growth of "useful knowledge," and by welcoming creative people from all over the world.^{[citation needed]} The bulk of research and development funding (64%) comes from the private sector, rather than from taxes.^[1]
The United States Constitution itself reflects the desire to encourage scientific creativity. It gives the United States Congress the power "to promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries." This clause formed the basis for the U.S. patent and copyright systems, whereby creators of original art and technology would get a government granted monopoly, which after a limited period would become free to all citizens, thereby enriching the public domain.

Contents 1 Early North American science 2 Science immigration 3 American applied science 4 The Atomic Age and "Big Science" 5 Telecom and technology 6 The "Space Age" 7 Medicine and health care 8 See also 9 References

Early North American science

Franklin, one of the first early American scientists.

In the early decades of its history, the United States was relatively isolated from Europe and also rather poor. At this stage America's scientific infrastructure was still quite primitive compared to the long-established societies, institutes, and universities in Europe.
Two of America's founding fathers were scientists of some repute. Benjamin Franklin conducted a series of experiments that deepened human understanding of electricity. Among other things, he proved what had been suspected but never before shown: that lightning is a form of electricity. Franklin also invented such conveniences as bifocal eyeglasses. He did not invent the Franklin stove, however, it was named after him but is a much simpler version of his original "Pennsylvania Fireplace."
Thomas Jefferson was a student of agriculture who introduced various types of rice, olive trees, and grasses into the New World. He stressed the scientific aspect of the Lewis and Clark expedition (1804–06), which explored the Pacific Northwest, and detailed, systematic information on the region's plants and animals was one of that expedition's legacies.
Like Franklin and Jefferson, most American scientists of the late 18th century were involved in the struggle to win American independence and forge a new nation. These scientists included the astronomer David Rittenhouse, the medical scientist Benjamin Rush, and the natural historian Charles Willson Peale.
During the American Revolution, Rittenhouse helped design the defenses of Philadelphia and built telescopes and navigation instruments for the United States' military services. After the war, Rittenhouse designed road and canal systems for the state of Pennsylvania. He later returned to studying the stars and planets and gained a worldwide reputation in that field.
As United States Surgeon General, Benjamin Rush saved countless lives of soldiers during the Revolutionary War by promoting hygiene and public health practices. By introducing new medical treatments, he made the Pennsylvania Hospital in Philadelphia an example of medical enlightenment, and after his military service, Rush established the first free clinic in the United States.
Charles Willson Peale is best remembered as an artist, but he also was a natural historian, inventor, educator, and politician. He created the first major museum in the United States, the Peale Museum in Philadelphia, which housed the young nation's only collection of North American natural history specimens. Peale excavated the bones of an ancient mastodon near West Point, New York; he spent three months assembling the skeleton, and then displayed it in his museum. The Peale Museum started an American tradition of making the knowledge of science interesting and available to the general public.

Science immigration

American political leaders' enthusiasm for knowledge also helped ensure a warm welcome for scientists from other countries. A notable early immigrant was the British chemist Joseph Priestley, who was driven from his homeland because of his dissenting politics. Priestley, who went to the United States in 1794, was the first of thousands of talented scientists who emigrated in search of a free, creative environment.
Other scientists had come to the United States to take part in the nation's rapid growth. Alexander Graham Bell, who arrived from Scotland by way of Canada in 1872, developed and patented the telephone and related inventions. Charles Steinmetz, who came from Germany in 1889, developed new alternating-current electrical systems at General Electric Company, and Vladimir Zworykin, who left Russia in 1919 and later invented a television camera. The Serb Nikola Tesla went to the United States in 1884, where he invented the brushless electrical motor based on rotating magnetic fields.
Into the early 1900s Europe remained the center of science research, notably in England and Germany. However with the rise of the Nazi party in Germany, a huge number of scientists left the country and travelled to the US. One of the first to do so was Albert Einstein in 1933. At his urging, and often with his support, a good percentage of Germany's theoretical physics community, previously the best in the world, left for the US. Enrico Fermi, came from Italy in 1938 and led the work that produced the world's first self-sustaining nuclear chain reaction.
In the post-war era the US was left in a position of unchallenged scientific leadership, being one of the few industrial countries not ravaged by war. Additionally, science and technology were seen to have greatly added to the Allied war victory, and were seen as absolutely crucial in the Cold War era. As a result, the US government became, for the first time, the largest single supporter of basic and applied scientific research. By the mid-1950s the research facilities in the US were second to none, and scientists were drawn to the US for this reason alone. The changing pattern can be seen in the winners of the Nobel Prizes in physics and chemistry. During the first half-century of Nobel Prizes – from 1901 to 1950 – American winners were in a distinct minority in the science categories. Since 1950, Americans have won approximately half of the Nobel Prizes awarded in the sciences. Compare the Evolution of Nobel Prizes by country.

Further information: Brain drain

American applied science

During the 19th century, Britain, France, and Germany were at the forefront of new ideas in science and mathematics. But if the United States lagged behind in the formulation of theory, it excelled in using theory to solve problems: applied science. This tradition had been born of necessity. Because Americans lived so far from the well-springs of Western science and manufacturing, they often had to figure out their own ways of doing things. When Americans combined theoretical knowledge with "Yankee ingenuity", the result was a flow of important inventions. The great American inventors include Robert Fulton (the steamboat); Samuel Morse (the telegraph); Eli Whitney (the cotton gin); Cyrus McCormick (the reaper); and Thomas Alva Edison, the most fertile of them all, with more than a thousand inventions credited to his name.
Edison was not always the first to devise a scientific application, but he was frequently the one to bring an idea to a practical finish. For example, the British engineer Joseph Swan built an incandescent electric lamp in 1860, almost 20 years before Edison. But Edison's light bulbs lasted much longer than Swan's, and they could be turned on and off individually, while Swan's bulbs could be used only in a system where several lights were turned on or off at the same time. Edison followed up his improvement of the light bulb with the development of electrical generating systems. Within 30 years, his inventions had introduced electric lighting into millions of homes.
Another landmark application of scientific ideas to practical uses was the innovation of the brothers Wilbur and Orville Wright. In the 1890s they became fascinated with accounts of German glider experiments and began their own investigation into the principles of flight. Combining scientific knowledge and mechanical skills, the Wright brothers built and flew several gliders. Then, on December 17, 1903, they successfully flew the first heavier-than-air, mechanically propelled airplane.
An American invention that was barely noticed in 1947 went on to usher in the Information Age. In that year John Bardeen, William Shockley, and Walter Brattain of Bell Laboratories drew upon highly sophisticated principles of quantum physics to invent the transistor, a small substitute for the bulky vacuum tube. This, and a device invented 10 years later, the integrated circuit, made it possible to package enormous amounts of electronics into tiny containers. As a result, book-sized computers of today can outperform room-sized computers of the 1960s, and there has been a revolution in the way people live – in how they work, study, conduct business, and engage in research.

The Atomic Age and "Big Science"

The mushroom cloud from the Mike shot, developed by United States Atomic Energy Commission

One of the most spectacular – and controversial – accomplishments of US technology has been the harnessing of nuclear energy. The concepts that led to the splitting of the atom were developed by the scientists of many countries, but the conversion of these ideas into the reality of nuclear fission was accomplished in the United States in early 1940s, both by many Americans but also aided tremendously by the influx of European intellectuals fleeing the growing conflagration sparked by Adolf Hitler and Benito Mussolini in Europe.
During these crucial years, a number of the most prominent European scientists, especially physicists, immigrated to the United States, where they would do much of their most important work; these included Hans Bethe, Albert Einstein, Enrico Fermi, Leó Szilárd, Edward Teller, Felix Bloch, Emilio Segrè, and Eugene Wigner, among many, many others. American academics worked hard to find positions at laboratories and universities for their European colleagues.
After German physicists split a uranium nucleus in 1938, a number of scientists concluded that a nuclear chain reaction was feasible and possible. The Einstein–Szilárd letter to President Franklin Roosevelt warned that this breakthrough would permit the construction of "extremely powerful bombs." This warning inspired an executive order towards the investigation of using uranium as a weapon, which later was superseded during World War II by the Manhattan Project the full Allied effort to be the first to build an atomic bomb. The project bore fruit when the first such bomb was exploded in New Mexico on July 16, 1945.
The development of the bomb and its use against Japan in August 1945 initiated the Atomic Age, a time of anxiety over weapons of mass destruction that has lasted through the Cold War and down to the anti-proliferation efforts of today. Even so, the Atomic Age has also been characterized by peaceful uses of nuclear power, as in the advances in nuclear power and nuclear medicine.
Along with the production of the atomic bomb, World War II also saw the entrance of an era known as "Big Science" with increased government patronage of scientific research. The advantage of a scientifically and technologically sophisticated country became all too apparent during wartime, and in the ideological Cold War to follow the importance of scientific strength in even peacetime applications became too much for the government to any more leave to philanthropy and private industry alone. This increased expenditure on scientific research and education propelled the United States to the forefront of the international scientific community—an amazing feat for a country which only a few decades before still had to send its most promising students to Europe for extensive scientific education.
The first US commercial nuclear power plant started operation in Illinois in 1956. At the time, the future for nuclear energy in the United States looked bright. But opponents criticized the safety of power plants and questioned whether safe disposal of nuclear waste could be assured. A 1979 accident at Three Mile Island in Pennsylvania turned many Americans against nuclear power. The cost of building a nuclear power plant escalated, and other, more economical sources of power began to look more appealing. During the 1970s and 1980s, plans for several nuclear plants were cancelled, and the future of nuclear power remains in a state of uncertainty in the United States.
Meanwhile, American scientists have been experimenting with other renewable energy, including solar power. Although solar power generation is still not economical in much of the United States, recent developments might make it more affordable.

Telecom and technology

For the past 80 years, the United States has been integral in fundamental advances in telecommunications and technology. For example, AT&T's Bell Laboratories spearheaded the American technological revolution with a series of inventions including the light emitted diode (LED), the transistor, the C programming language, and the UNIX computer operating system. SRI International and Xerox PARC in Silicon Valley helped give birth to the personal computer industry, while ARPA and NASA funded the development of the ARPANET and the Internet.

The "Space Age"

The Space Shuttle takes off on a manned mission to space.

Running almost in tandem with the Atomic Age has been the Space Age. American Robert Goddard was one of the first scientists to experiment with rocket propulsion systems. In his small laboratory in Worcester, Massachusetts, Goddard worked with liquid oxygen and gasoline to propel rockets into the atmosphere, and in 1926 successfully fired the world's first liquid-fuel rocket which reached a height of 12.5 meters. Over the next 10 years, Goddard's rockets achieved modest altitudes of nearly two kilometers, and interest in rocketry increased in the United States, Britain, Germany, and the Soviet Union.
As Allied forces advanced during World War II, both the American and Russian forces searched for top German scientists who could be claimed as "spoils" for their country. The American effort to bring home German rocket technology in Operation Paperclip, and the bringing of German rocket scientist Wernher von Braun (who would later sit at the head of a NASA center) stand out in particular.
Expendable rockets provided the means for launching artificial satellites, as well as manned spacecraft. In 1957 the Soviet Union launched the first satellite, Sputnik I, and the United States followed with Explorer I in 1958. The first manned space flights were made in early 1961, first by Soviet cosmonaut Yuri Gagarin and then by American astronaut Alan Shepard.
From those first tentative steps, to The 1969 Apollo program landing on the Moon and the partially reusable Space Shuttle, the American space program brought forth a breathtaking display of applied science. Communications satellites transmit computer data, telephone calls, and radio and television broadcasts. Weather satellites furnish the data necessary to provide early warnings of severe storms. Global positioning satellites were first developed in the US starting around 1972, and became fully operational by 1994. Interplanetary probes and space telescopes began a golden age of planetary science and advanced a wide variety of astronomical work.

Medicine and health care

As in physics and chemistry, Americans have dominated the Nobel Prize for physiology or medicine since World War II. The private sector has been the focal point for biomedical research in the United States, and has played a key role in this achievement. As of 2000, for-profit industry funded 57%, non-profit private organizations such as the Howard Hughes Medical Institute funded 7%, and the tax-funded National Institutes of Health funded 36% of medical research in the U.S.^[2] However, by 2003, the NIH funded only 28% of medical research funding; funding by private industry increased 102% from 1994 to 2003.^[3]
The National Institutes of Health consists of 24 separate institutes in Bethesda, Maryland. The goal of NIH research is knowledge that helps prevent, detect, diagnose, and treat disease and disability. At any given time, grants from the NIH support the research of about 35,000 principal investigators. Five Nobel Prize-winners have made their prize-winning discoveries in NIH laboratories.
NIH research has helped make possible numerous medical achievements. For example, mortality from heart disease, the number-one killer in the United States, dropped 41 percent between 1971 and 1991. The death rate for strokes decreased by 59 percent during the same period. Between 1991 and 1995, the cancer death rate fell by nearly 3 percent, the first sustained decline since national record-keeping began in the 1930s. And today more than 70 percent of children who get cancer are cured.
With the help of the NIH, molecular genetics and genomics research have revolutionized biomedical science. In the 1980s and 1990s, researchers performed the first trial of gene therapy in humans and are now able to locate, identify, and describe the function of many genes in the human genome.
Research conducted by universities, hospitals, and corporations also contributes to improvement in diagnosis and treatment of disease. NIH funded the basic research on Acquired Immune Deficiency Syndrome (AIDS), for example, but many of the drugs used to treat the disease have emerged from the laboratories of the American pharmaceutical industry; those drugs are being tested in research centers across the country.

The Hunt for Nazi Scientists The Terrifying Weapons

The Hunt for Nazi Scientists

The Terrifying Weapons

When the Germans formally surrendered to the Allies on May 8, 1945, their reign of terror ended, but the terrifying weapons created by Nazi scientists lived on and would eventually shape both the Cold War and the space age.
The V-2
On April 11, 1945, American agents discovered the secret underground factory in Germany where thousands of V-2 missiles had been built. Because the region was in part of Germany that was to become Russian territory after the war, American forces removed what they could: hundreds of trainloads of V-2s and their parts, which were then shipped off to the United States along with Germany’s chief rocket scientist, Wernher von Braun, and more than one hundred of his engineers. The V-2s were used in rocket tests in the States; meanwhile, von Braun and his colleagues set about to design a new breed of missile. Over the next few decades, their efforts, building on the design of the V-2, produced the Redstone, Jupiter, Jupiter-C, Pershing, and Saturn rockets (which launched the Apollo spacecraft and Skylab into orbit)
The Russians, however, also got their hands on both V-2 technology and members of von Braun’s German rocket design team. It almost cost the United States the space race. The V-2 design was copied for Russia’s first missile, the R-1. On October 4, 1957, a later version of the rocket, the R-7, launched Sputnik — the world’s first artificial satellite — into orbit.
Rocket Planes and Jet Fighters
The British intelligence unit, 30 AU, captured radical aircraft designer Helmut Walter a few days before the end of the war. Walter soon gave up the location of the German airfields that housed the Messerschmitt 163 — the Nazi’s “flying bomb.” The revolutionary tailless aircraft, powered by an explosive combination of rocket fuels, was acquired by the Americans, British, and Russians. Each country planned to use the technology in the development of their own new aircraft. It was another of Walter’s designs, the Messerschmitt 262, which shaped the course of future Cold War conflicts.
The sleek Me-262, a successor to the Me-163, was the world’s first operational jet-powered fighter plane. First flown in July 1942, the Me-262 could accelerate to 540 miles an hour — more than 100 miles an hour faster than the best Allied craft — and could sustain 60 to 90 minutes of flight (the Me-163, in contrast, sputtered out after just 8 minutes). The impressive machine became the model for the American F-86 Sabre jet fighter and the Russian MiG-15.
The Bomb
Beginning in 1938, when German scientists first discovered fission — the basic process that makes nuclear weapons possible — the Allies worried that Germany would soon develop an atomic bomb. Those fears were dispelled just weeks before the end of the war, when the crack agents of the American Alsos team discovered a Nazi nuclear reactor under construction in a cave beneath a castle in Haigerloch, Germany. (The German nuclear scientists, American bomb designers soon realized, were no farther along in producing the bomb than the Americans had been back in 1942.) Days later, buried in a nearby field, the agents uncovered more than two tons of radioactive uranium. That uranium, along with thousands of pounds of uranium from other sites in Germany, was shipped to Manhattan Project scientists for use in the American bomb effort.

German nuclear energy project

Germany nuclear energy project
The German experimental nuclear pile at Haigerloch.
Active	1939–1945 (the program was cancelled due to the Fall of Berlin)
Country	Germany
Allegiance	Germany
Branch	Army Ordnance Office Reich Research Council
Type	Nuclear Weapon Research
Role	development of atomic and radiological weapon
Part of	Wehrmacht
Headquarters	Berlin
Nickname	Uranverein Uranprojekt
Patron	Adolf Hitler
Motto	Deutsche Physik (German Physics)
Engagements	World war II Fall of Berlin Operation Paperclip Operation Alsos Operation Epsilon Russian Alsos
Disbanded	1945 (end of World war II)
Commanders
Program Plenipotentiary	Marshal Hermann Göring
Minister for Armaments and Ammunition	Albert Speer
Uranverein' Reichofficer	Walther Gerlach
Reichsdirector of the Reichsforschungsrat	Rudolf Mentzel Kurt Diebner

The German nuclear energy project (German: Uranprojekt; informally known as the Uranverein; English: Uranium Club), was an attempted clandestine scientific effort led by Germany to develop and produce atomic weapons during the events of World War II. This program started in April 1939, just months after the discovery of nuclear fission in January 1939, but ended only months later, due to German invasion of Poland, where many notable physicists were drafted into the Wehrmacht. However, the second effort began under the administrative auspices of the Wehrmacht's Heereswaffenamt on the day World War II began (1 September 1939). The program eventually expanded into three main efforts: the Uranmaschine (nuclear reactor), uranium and heavy water production, and uranium isotope separation. Eventually it was assessed that nuclear fission would not contribute significantly to ending the war, and in January 1942, the Heereswaffenamt turned the program over to the Reich Research Council while continuing to fund the program. At this time, the program split up between nine major institutes where the directors dominated the research and set their own objectives. At that time, the number of scientists working on applied nuclear fission began to diminish, with many applying their talents to more pressing war-time demands.
The most influential people in the Uranverein were Kurt Diebner, Abraham Esau, Walther Gerlach, and Erich Schumann; Schumann was one of the most powerful and influential physicists in Germany. Diebner, throughout the life of the nuclear energy project, had more control over nuclear fission research than did Walther Bothe, Klaus Clusius, Otto Hahn, Paul Harteck, or Werner Heisenberg. Abraham Esau was appointed as Hermann Göring's plenipotentiary for nuclear physics research in December 1942; Walther Gerlach succeeded him in December 1943.
Politicization of the German academia under the National Socialist regime had driven many physicists, engineers, and mathematicians out of Germany as early as 1933. Those of Jewish heritage who did not leave were quickly purged from German institutions, further thinning the ranks of academia. The politicization of the universities, along with the demands for manpower by the German armed forces (many scientists and technical personnel were conscripted, despite possessing useful skills), would eventually all but eliminate a generation of physicists.^[1]
At the end of the war, the Allied powers competed to obtain surviving components of the nuclear industry (personnel, facilities, and materiel), as they did with the V-2 program.

Contents 1 Discovery of nuclear fission 2 First Uranverein 2.1 Another notification 3 Second Uranverein 4 Isotope separation 5 Internal reports 6 Politicisation 6.1 Emigrations 6.2 Heisenberg affair 6.3 Missing generation of physicists 6.4 Autonomy and accommodation 7 Exploitation and denial 7.1 American and British 7.2 French 7.3 Soviet 8 Comparison of the Manhattan Project and the Uranverein 9 Recent developments 10 See also 11 Bibliography 12 Further reading 13 Notes 14 External links

Discovery of nuclear fission

Main articles: History of physics, History of nuclear weapons, and World War II

In December 1938, the German chemists Otto Hahn and Fritz Strassmann sent a manuscript to the science journal Naturwissenschaften ("Natural Science") reporting they had detected the element barium after bombarding uranium with neutrons;^[2] simultaneously, they communicated these results to Lise Meitner, who had in July of that year fled to the Netherlands and then went to Sweden.^[3] Meitner, and her nephew Otto Robert Frisch, correctly interpreted these results as being nuclear fission.^[4] Frisch confirmed this experimentally on 13 January 1939.^[5][6]

First Uranverein

Paul Harteck was director of the physical chemistry department at the University of Hamburg and an advisor to the Heereswaffenamt (HWA, Army Ordnance Office). On 24 April 1939, along with his teaching assistant Wilhelm Groth, Harteck made contact with the Reichskriegsministerium (RKM, Reich Ministry of War) to alert them to the potential of military applications of nuclear chain reactions. Two days earlier, on 22 April 1939, after hearing a colloquium paper by Wilhelm Hanle on the use of uranium fission in a Uranmaschine (uranium machine, i.e., nuclear reactor), Georg Joos, along with Hanle, notified Wilhelm Dames, at the Reichserziehungsministerium (REM, Reich Ministry of Education), of potential military applications of nuclear energy. The communication was given to Abraham Esau, head of the physics section of the Reichsforschungsrat (RFR, Reich Research Council) at the REM's undersecretary Rudolf Mentzel. On 29 April, a group, organized by Esau, met with Rudolf Mentzel at the REM to discuss the potential of a sustained nuclear chain reaction. The group included the physicists Walther Bothe, Robert Döpel, Hans Geiger, Wolfgang Gentner (probably sent by Walther Bothe), Wilhelm Hanle, Gerhard Hoffmann, and Georg Joos; Peter Debye was invited, but he did not attend. After this, informal work began at the Georg-August University of Göttingen by Joos, Hanle, and their colleague Reinhold Mannkopff; the group of physicists was known informally as the first Uranverein (Uranium Club) and formally as Arbeitsgemeinschaft für Kernphysik. The group's work was discontinued in August 1939, when the three were called to military training.^{[7][8][9][10]}

Another notification

The industrial firm Auergesellschaft had a substantial amount of "waste" uranium from which it had extracted radium. After reading a June 1939 paper by Siegfried Flügge, on the technical use of nuclear energy from uranium,^[11][12] Riehl recognized a business opportunity for the company, and in July he went to the HWA (Heereswaffenamt, Army Ordnance Office) to discuss the production of uranium. The HWA was interested and Riehl committed corporate resources to the task. The HWA eventually provided an order for the production of uranium oxide, which took place in the Auergesellschaft plant in Oranienburg, north of Berlin.^[13][14]

Second Uranverein

The second Uranverein began after the Heereswaffenamt (HWA, Army Ordinance Office) squeezed out the Reichsforschungsrat (RFR, Reich Research Council) of the Reichserziehungsministerium (REM, Reich Ministry of Education) and started the formal German nuclear energy project under military auspices. The second Uranverein was formed on 1 September 1939, the day World War II began, and it had its first meeting on 16 September 1939. The meeting was organized by Kurt Diebner, advisor to the HWA, and held in Berlin. The invitees included Walther Bothe, Siegfried Flügge, Hans Geiger, Otto Hahn, Paul Harteck, Gerhard Hoffmann, Josef Mattauch, and Georg Stetter. A second meeting was held soon thereafter and included Klaus Clusius, Robert Döpel, Werner Heisenberg, and Carl Friedrich von Weizsäcker. Also at this time, the Kaiser-Wilhelm Institut für Physik (KWIP, Kaiser Wilhelm Institute for Physics, after World War II the Max Planck Institute for Physics), in Berlin-Dahlem, was placed under HWA authority, with Diebner as the administrative director, and the military control of the nuclear research commenced.^[9][10][15]
When it was apparent that the nuclear energy project would not make a decisive contribution to ending the war in the near term, control of the KWIP was returned in January 1942 to its umbrella organization, the Kaiser-Wilhelm Gesellschaft (KWG, Kaiser Wilhelm Society, after World War II the Max-Planck Gesellschaft), and HWA control of the project was relinquished to the RFR in July 1942. The nuclear energy project thereafter maintained its kriegswichtig (important for the war) designation and funding continued from the military. However, the German nuclear power project was then broken down into the following main areas: uranium and heavy water production, uranium isotope separation, and the Uranmaschine (uranium machine, i.e., nuclear reactor). Also, the project was then essentially split up between a number of institutes, where the directors dominated the research and set their own research agendas.^[9][16][17] The dominant personnel, facilities, and areas of research were:^[18][19][20]

• Walther Bothe — Director of the Institut für Physik (Institute for Physics) at the Kaiser-Wilhelm Institut für medizinische Forschung (KWImF, Kaiser Wilhelm Institute for Medical Research, after 1948 the Max-Planck-Institut für medizinische Forschung), in Heidelberg.
  • Measurement of nuclear constants. (6 physicists)
• Klaus Clusius — Director of the Institute for Physical Chemistry at the Ludwig Maximilian University of Munich
  • Isotope separation and heavy water production. (ca. 4 physical chemists and physicists)
• Kurt Diebner — Director of the HWA Versuchsstelle (testing station) in Gottow; Diebner, was also director the RFR experimental station in Stadtilm, Thuringia. He was also an advisor to the HWA on nuclear physics.
  • Measurement of nuclear constants. (ca. 6 physicists)
• Otto Hahn — Director of the Kaiser-Wilhelm-Institut für Chemie (KWIC, Kaiser Wilhelm Institute for Chemistry, after World War II the Max Planck Institut für Chemie — Otto Hahn Institut), in Berlin-Dahlem.
  • Transuranic elements, fission products, isotope separation, and measurement of nuclear constants. (ca. 6 chemists and physicists)
• Paul Harteck — Director of the Physical Chemistry Department of the University of Hamburg.
  • Heavy water production and isotope production. (5 physical chemists, physicists, and chemists)
• Werner Heisenberg — Director of the Department of Theoretical Physics at the University of Leipzig until summer 1942. Thereafter acting director of the Kaiser-Wilhelm-Institut für Physik (Kaiser Wilhelm Institute for Physics), in Berlin-Dahlem.
  • Uranmaschine, isotope separation, and measurement of nuclear constants. (ca. 7 physicists and physical chemists).
• Hans Kopfermann — Director of the Second Experimental Physics Institute at the Georg-August University of Göttingen.
  • Isotope separation. (2 physicists)
• Nikolaus Riehl — Scientific Director of the Auergesellschaft.
  • Uranium production. (ca. 3 physicists and physical chemists)
• Georg Stetter — Director of the II. Physikalisches Institut (Second Physics Institute) at the University of Vienna.
  • Transuranic elements and measurement of nuclear constants. (ca. 6 physicists and physical chemists)

The point in 1942, when the army relinquished its control of the German nuclear energy project, was the zenith of the project relative to the number of personnel devoted to the effort. There were only about seventy scientists working on the project, with about forty devoting more than half their time to nuclear fission research. After this, the number of scientists working on applied nuclear fission diminished dramatically. Many of the scientists not working with the main institutes stopped working on nuclear fission and devoted their efforts to more pressing war related work.^[21]
On 4 June 1942, a conference initiated by the "Reich Minister for Armament and Ammunition" Albert Speer regarding the nuclear energy project, had decided its continuation merely for the aim of energy production.^[22] On 9 June 1942, Adolf Hitler issued a decree for the reorganization of the RFR as a separate legal entity under the Reichsministerium für Bewaffnung und Munition (RMBM, Reich Ministry for Armament and Ammunition, after autumn 1943 the Reich Ministry for Armament and War Production); the decree appointed Reich Marshal Hermann Göring as the president.^[23] The reorganization was done under the initiative of Minister Albert Speer of the RMBM; it was necessary as the RFR under Minister Bernhard Rust was ineffective and not achieving its purpose.^[24] It was the hope that Göring would manage the RFR with the same discipline and efficiency as he had in the aviation sector. A meeting was held on 6 July 1942 to discuss the function of the RFR and set its agenda. The meeting was a turning point in National Socialism's attitude towards science, as well as recognition that its policies which drove Jewish scientists out of Germany were a mistake, as the Reich needed their expertise. Abraham Esau was appointed on 8 December 1942 as Hermann Göring's Bevollmächtigter (plenipotentiary) for nuclear physics research under the RFR; in December 1943, Esau was replaced by Walther Gerlach. In the final analysis, placing the RFR under Göring's administrative control had little effect on the German nuclear energy project.^{[25][26][27][28]}
Over time, the HWA and then the RFR controlled the German nuclear energy project. The most influential people were Kurt Diebner, Abraham Esau, Walther Gerlach, and Erich Schumann. Schumann was one of the most powerful and influential physicists in Germany. Schumann was director of the Physics Department II at the Frederick William University (later, University of Berlin), which was commissioned and funded by the Oberkommando des Heeres (OKH, Army High Command) to conduct physics research projects. He was also head of the research department of the HWA, assistant secretary of the Science Department of the OKW, and Bevollmächtigter (plenipotentiary) for high explosives. Diebner, throughout the life of the nuclear energy project, had more control over nuclear fission research than did Walther Bothe, Klaus Clusius, Otto Hahn, Paul Harteck, or Werner Heisenberg.^[29][30]

Isotope separation

Heinz Ewald, a member of the Uranverein, had proposed an electromagnetic isotope separator, which was thought applicable to U²³⁵ production and enrichment. This was picked up by Manfred von Ardenne, who ran a private research establishment.
In 1928, von Ardenne had come into his inheritance with full control as to how it could be spent, and he established his private research laboratory the Forschungslaboratoriums für Elektronenphysik,^[31] in Berlin-Lichterfelde, to conduct his own research on radio and television technology and electron microscopy. He financed the laboratory with income he received from his inventions and from contracts with other concerns. For example, his research on nuclear physics and high-frequency technology was financed by the Reichspostministerium (RPM, Reich Postal Ministry), headed by Wilhelm Ohnesorge. Von Ardenne attracted top-notch personnel to work in his facility, such as the nuclear physicist Fritz Houtermans, in 1940.
Von Ardenne had also conducted research on isotope separation.^[32][33] Taking Ewald's suggestion he began building a prototype for the RPM. The work was hampered by war shortages and ultimately ended by the war.^[34]

Internal reports

Reports from the research conducted were published in Kernphysikalische Forschungsberichte (Research Reports in Nuclear Physics), an internal publication of the Uranverein. The reports were classified Top Secret, they had very limited distribution, and the authors were not allowed to keep copies. The reports were confiscated under the Allied Operation Alsos and sent to the United States Atomic Energy Commission for evaluation. In 1971, the reports were declassified and returned to Germany. The reports are available at the Karlsruhe Nuclear Research Center and the American Institute of Physics.^[35][36]
Individual reports are cited on the pages for some of the research participants in the Uranverein; see for example Friedrich Bopp, Kurt Diebner, Klara Döpel, Robert Döpel, Siegfried Flügge, Paul Harteck, Walter Herrmann, Karl-Heinz Höcker, Fritz Houtermans, Horst Korsching, Georg Joos, Heinz Pose, Carl Ramsauer, Fritz Strassmann, Karl Wirtz, and Karl Zimmer.

Politicisation

Two factors which had deleterious effects on the nuclear energy project were the politicisation of the education system under National Socialism and the rise of the Deutsche Physik movement, which was anti-Semitic and had a bias against theoretical physics, especially including quantum mechanics.^[37]

Emigrations

Adolf Hitler took power on 30 January 1933. On 7 April, the Law for the Restoration of the Professional Civil Service was enacted; this law, and its subsequent related ordinances, politicized the education system in Germany. This had immediate deleterious effects on the physics capabilities of Germany. Furthermore, combined with the deutsche Physik movement, the deleterious effects were intensified and prolonged. The consequences to physics in Germany and its subfield of nuclear physics were multifaceted.
An immediate consequence upon passage of the law was that it produced both quantitative and qualitative losses to the physics community. Numerically, it has been estimated that a total of 1,145 university teachers, in all fields, were driven from their posts, which represented about 14% of the higher learning institutional staff members in 1932–1933.^[38] Out of 26 German nuclear physicists cited in the literature before 1933, 50% emigrated.^[39] Qualitatively, 10 physicists and four chemists who had won or would win the Nobel Prize emigrated from Germany shortly after Hitler came to power, most of them in 1933.^[40] These 14 scientists were: Hans Bethe, Felix Bloch, Max Born, Albert Einstein, James Franck, Peter Debye, Dennis Gabor, Fritz Haber, Gerhard Herzberg, Victor Hess, George de Hevesy, Erwin Schrödinger, Otto Stern, and Eugene Wigner. Britain and the USA were often the recipients of the talent which left Germany.^[41] The University of Göttingen had 45 dismissals from the staff of 1932–1933, for a loss of 19%.^[38] Eight students, assistants, and colleagues of the Göttingen theoretical physicist Max Born left Europe after Hitler came to power and eventually found work on the Manhattan Project, thus helping the United States, Britain and Canada to develop the atomic bomb; they were Enrico Fermi,^[42] James Franck, Maria Goeppert-Mayer, Robert Oppenheimer, Edward Teller, Victor Weisskopf, Eugene Wigner, and John von Neumann.^[43] Otto Robert Frisch, who with Rudolf Peierls first calculated the critical mass of U-235 needed for an explosive, was also a Jewish refugee.
Max Planck, the father of quantum theory, had been right in assessing the consequences of National Socialist policies. In 1933, Planck, as president of the Kaiser Wilhelm Gesellschaft (Kaiser Wilhelm Society), met with Adolf Hitler. During the meeting, Planck told Hitler that forcing Jewish scientists to emigrate would mutilate Germany and the benefits of their work would go to foreign countries. Hitler responded with a rant against Jews and Planck could only remain silent and then take his leave. The National Socialist regime would only come around to the same conclusion as Planck in the 6 July 1942 meeting regarding the future agenda of the Reichsforschungsrat (RFR, Reich Research Council), but by then it was too late.^[25][44]

Heisenberg affair

The politicisation of the education system essentially replaced academic tradition and excellence with ideological adherence and trappings, such as membership in National Socialist organisations, such as the Nationalsozialistische Deutsche Arbeiterpartei (NSDAP, National Socialist German Workers Party), the Nationalsozialistischer Deutscher Dozentenbund (NSDDB, National Socialist German University Lecturers League), and the Nationalsozialistischer Deutscher Studentenbund (NSDStB, National Socialist German Student League). The politicization can be illustrated with the conflict which evolved when a replacement for Arnold Sommerfeld was sought in view of his emeritus status. The conflict involved one of the prominent Uranverein participants, Werner Heisenberg.
On 1 April 1935 Arnold Sommerfeld, Heisenberg's teacher and doctoral advisor at the University of Munich, achieved emeritus status. However, Sommerfeld stayed on as his own temporary replacement during the selection process for his successor, which took until 1 December 1939. The process was lengthy due to academic and political differences between the Munich Faculty's selection and that of both the Reichserziehungsministerium (REM, Reich Education Ministry) and the supporters of Deutsche Physik. In 1935, the Munich Faculty drew up a candidate list to replace Sommerfeld as ordinarius professor of theoretical physics and head of the Institute for Theoretical Physics at the University of Munich. There were three names on the list: Werner Heisenberg, who received the Nobel Prize in Physics in 1932, Peter Debye, who would receive the Nobel Prize in Chemistry in 1936, and Richard Becker — all former students of Sommerfeld. The Munich Faculty was firmly behind these candidates, with Heisenberg as their first choice. However, supporters of Deutsche Physik and elements in the REM had their own list of candidates and the battle commenced, dragging on for over four years. During this time, Heisenberg came under vicious attack by the supporters of deutsche Physik. One such attack was published in Das Schwarze Korps, the newspaper of the Schutzstaffel, or SS, headed by Heinrich Himmler. In the editorial, Heisenberg was called a "White Jew" who should be made to "disappear."^[45] These verbal attacks were taken seriously, as Jews were subject to physical violence and incarceration at the time. Heisenberg fought back with an editorial and a letter to Himmler, in an attempt to get a resolution to this matter and regain his honor. At one point, Heisenberg's mother visited Himmler's mother to help bring a resolution to the affair. The two women knew each other as a result of Heisenberg's maternal grandfather and Himmler's father being rectors and members of a Bavarian hiking club. Eventually, Himmler settled the Heisenberg affair by sending two letters, one to SS-Gruppenführer Reinhard Heydrich and one to Heisenberg, both on 21 July 1938. In the letter to Heydrich, Himmler said Germany could not afford to lose or silence Heisenberg as he would be useful for teaching a generation of scientists. To Heisenberg, Himmler said the letter came on recommendation of his family and he cautioned Heisenberg to make a distinction between professional physics research results and the personal and political attitudes of the involved scientists. The letter to Heisenberg was signed under the closing "Mit freundlichem Gruss und, Heil Hitler!" ("With friendly greetings, Heil Hitler!")^[46] Overall, the settlement of the Heisenberg affair was a victory for academic standards and professionalism. However, the replacement of Sommerfeld by Wilhelm Müller on 1 December 1939 was a victory of politics over academic standards. Müller was not a theoretical physicist, had not published in a physics journal, and was not a member of the Deutsche Physikalische Gesellschaft (DPG, German Physical Society); his appointment as a replacement for Sommerfeld was considered a travesty and detrimental to educating a new generation of theoretical physicists.^{[46][47][48][49][50]}

Missing generation of physicists

Politicization of the academic community, combined with the impact of the deutsche Physik movement and other policies, such as drafting physicists to fight in the war (e.g., Paul O. Müller, a member of the Uranverein who was killed at the Russian front), had the net effect of bringing about a missing generation of physicists. At the close of the war, physicists born between 1915 and 1925 were almost nonexistent.^[51]

Autonomy and accommodation

Members of the Uranverein, Wolfgang Finkelnburg, Werner Heisenberg, Carl Ramsauer, and Carl Friedrich von Weizsäcker were effective in countering the politicisation of academia and effectively putting an end to the influence of the deutsche Physik movement. However, in order to do this they were, as were many scientists, caught between autonomy and accommodation.^[52] Essentially, they would have to legitimize the National Socialist system by compromise and collaboration.^[53]
During the period in which Deutsche Physik was gaining prominence, a foremost concern of the great majority of scientists was to maintain autonomy against political encroachment.^[54] Some of the more established scientists, such as Max von Laue, could demonstrate more autonomy than the younger and less established scientists.^[55] This was, in part, due to political organizations, such as the Nationalsozialistischer Deutscher Dozentenbund (National Socialist German University Lecturers League), whose district leaders had a decisive role in the acceptance of an Habilitationsschrift, which was a prerequisite to attaining the rank of Privatdozent necessary to becoming a university lecturer.^[56] While some with ability joined such organizations out of tactical career considerations, others with ability and adherence to historical academic standards joined these organizations to moderate their activities. This was the case of Finkelnburg.^[57][58] It was in the summer of 1940 that Finkelnburg became an acting director of the NSDDB at Technische Hochschule, Darmstadt.^[59] As such, he organized the Münchner Religionsgespräche, which took place on 15 November 1940 and was known as the Munich Synod . The Münchner Religionsgespräche was an offensive against deutsche Physik.^[60] While the technical outcome may have been thin, it was a political victory against deutsche Physik.^[57] Also, in part, it was Finkelnburg's role in organising this event that influenced Carl Ramsauer, as president of the Deutsche Physikalische Gesellschaft, to select Finkelnburg in 1941 as his deputy.^[61] Finkelnburg served in this capacity until the end of World War II.
Early in 1942, as president of the DPG, Ramsauer, on Felix Klein's initiative and with the support of Ludwig Prandtl, submitted a petition to Reich Minister Bernhard Rust, at the Reichserziehungsministerium (Reich Education Ministry). The petition, a letter and six attachments,^[62] addressed the atrocious state of physics instruction in Germany, which Ramsauer concluded was the result of politicization of education.^[63]

Exploitation and denial

Near the end of World War II, the principal Allied war powers made plans for exploitation of German science. In light of the implications of nuclear weapons, German nuclear fission and related technologies were singled out for special attention. In addition to exploitations, denial was an element of their efforts, i.e., the Americans and Russians conducted their respective operations to try to deny German technology, personnel, and material to the other party. Application of denial often meant getting there first, which to some extent put the Russians at a disadvantage in some geographic locations, even if the area was to be in the Russian zone of occupation. When it came to applications of exploitation and denial, all parties were sometimes heavy-handed.^{[64][65][66][67][68]}
A general US denial and exploitation effort was Operation Paperclip. Operations directed specifically towards German nuclear fission were Operation Alsos and Operation Epsilon, the latter being done in collaboration with the British. In lieu of the codename for the Russian operation, if it had one, it has been referred to by Oleynikov as the Russian "Alsos".^[69]

American and British

Berlin had been a location of many German scientific research facilities. To limit casualties and loss of equipment, many of these facilities were dispersed to other locations in the latter years of the war.
Unfortunately for the Russians, the Kaiser-Wilhelm-Institut für Physik (KWIP, Kaiser Wilhelm Institute for Physics) had mostly been moved in 1943 and 1944 to Hechingen and its neighboring town of Haigerloch, on the edge of the Black Forest, which eventually became the French occupation zone. This move allowed the Americans to take into custody a large number of German scientists associated with nuclear research. The only section of the institute which remained in Berlin was the low-temperature physics section, headed by Ludwig Bewilogua, who was in charge of the exponential uranium pile.^[70][71]
Nine of the prominent German scientists who published reports in Kernphysikalische Forschungsberichte as members of the Uranverein^[72] were picked up by Operation Alsos and incarcerated in England under Operation Epsilon: Erich Bagge, Kurt Diebner, Walther Gerlach, Otto Hahn, Paul Harteck, Werner Heisenberg, Horst Korsching, Carl Friedrich von Weizsäcker, and Karl Wirtz. Also, incarcerated was Max von Laue, although he had nothing to do with the nuclear energy project. Goudsmit, the chief scientific advisor to Operation Alsos, thought von Laue might be beneficial to the postwar rebuilding of Germany and would benefit from the high level contacts he would have in England.^[73]

Oranienburg Plant

With the interest of the Heereswaffenamt (HWA, Army Ordnance Office), Nikolaus Riehl, and his colleague Günter Wirths, set up an industrial-scale production of high-purity uranium oxide at the Auergesellschaft plant in Oranienburg. Adding to the capabilities in the final stages of metallic uranium production were the strength's of the Degussa corporation's capabilities in metals production.^[74][75]
The Oranienburg plant provided the uranium sheets and cubes for the Uranmaschine experiments conducted at the KWIP and the Versuchsstelle (testing station) of the Heereswaffenamt (Army Ordnance Office) in Gottow. The G-1 experiment^[76] performed at the HWA testing station, under the direction of Kurt Diebner, had lattices of 6,800 uranium oxide cubes (about 25 tons), in the nuclear moderator paraffin.^[14][77]
Work of the American Operation Alsos teams, in November 1944, uncovered leads which took them to a company in Paris that handled rare earths and had been taken over by the Auergesellschaft. This, combined with information gathered in the same month through an Alsos team in Strasbourg, confirmed that the Oranienburg plant was involved in the production of uranium and thorium metals. Since the plant was to be in the future Soviet zone of occupation and the Russian troops would get there before the Allies, General Leslie Groves, commander of the Manhattan Project, recommended to General George Marshall that the plant be destroyed by aerial bombardment, in order to deny its uranium production equipment to the Russians. On 15 March 1945, 612 B-17 Flying Fortress bombers of the Eighth Air Force dropped 1,506 tons of high-explosive and 178 tons of incendiary bombs on the plant. Riehl visited the site with the Russians and said that the facility was mostly destroyed. Riehl also recalled long after the war that the Russians knew precisely why the Americans had bombed the facility — the attack had been directed at them rather than the Germans.^{[78][79][80][81][82]}

French

From 1941 to 1947, Fritz Bopp was a staff scientist at the KWIP, and worked with the Uranverein. In 1944, when most of the KWIP was evacuated to Hechingen in Southern Germany due to air raids on Berlin, he went there too, and he was the Institute's Deputy Director there. When the American Alsos Mission evacuated Hechingen and Haigerloch, near the end of World War II, French armed forces occupied Hechingen. Bopp did not get along with them and described the initial French policy objectives towards the KWIP as exploitation, forced evacuation to France, and seizure of documents and equipment. The French occupation policy was not qualitatively different from that of the American and Russian occupation forces, it was just carried out on a smaller scale. In order to put pressure on Bopp to evacuate the KWIP to France, the French Naval Commission imprisoned him for five days and threatened him with further imprisonment if he did not cooperate in the evacuation. During his imprisonment, the spectroscopist Hermann Schüler, who had a better relationship with the French, persuaded the French to appoint him as Deputy Director of the KWIP. This incident caused tension between the physicists and spectroscopists at the KWIP and within its umbrella organization the Kaiser-Wilhelm Gesellschaft (Kaiser Wilhelm Society).^{[83][84][85][86]}

Soviet

At the close of World War II, the Soviet Union had special search teams operating in Austria and Germany, especially in Berlin, to identify and "requisition" equipment, material, intellectual property, and personnel useful to the Soviet atomic bomb project. The exploitation teams were under the Soviet Alsos and they were headed by Lavrentij Beria's deputy, Colonel General A. P. Zavenyagin. These teams were composed of scientific staff members, in NKVD officer's uniforms, from the bomb project's only laboratory, Laboratory No. 2, in Moscow, and included Yulij Borisovich Khariton, Isaak Konstantinovich Kikoin, and Lev Andreevich Artsimovich. Georgij Nikolaevich Flerov had arrived earlier, although Kikoin did not recall a vanguard group. Targets on the top of their list were the Kaiser-Wilhelm Institut für Physik (KWIP, Kaiser Wilhelm Institute for Physics), the Frederick William University (today, the University of Berlin), and the Technische Hochschule Berlin (today, the Technische Universität Berlin (Technical University of Berlin).^[87][88][89]
German physicists who worked on the Uranverein and were sent to the Soviet Union to work on the Soviet atomic bomb project included: Werner Czulius, Robert Döpel, Walter Herrmann, Heinz Pose, Ernst Rexer, Nikolaus Riehl, and Karl Zimmer. Günter Wirths, while not a member of the Uranverein, worked for Riehl at the Auergesellschaft on reactor-grade uranium production and was also sent to the Soviet Union.
Zimmer's path to work on the Soviet atomic bomb project was through a prisoner of war camp in Krasnogorsk, as was that of his colleagues Hans-Joachim Born and Alexander Catsch from the Kaiser-Wilhelm Institut für Hirnforschung (KWIH, Kaiser Wilhelm Institute for Brain Research, today the Max-Planck Institut für Hirnforschung), who worked there for N. V. Timofeev-Resovskij, director of the Abteilung für Experimentelle Genetik (Department of Experimental Genetics). All four eventually worked for Riehl in the Soviet Union at Laboratory B in Sungul'.^[90][91]
Von Ardenne, who had worked on isotope separation for the Reichspostministerium (Reich Postal Ministry), was also sent to the Soviet Union to work on their atomic bomb project, along with Gustav Hertz, Nobel laureate and director of Research Laboratory II at Siemens, Peter Adolf Thiessen, director of the Kaiser-Wilhelm Institut für physikalische Chemie und Elektrochemie (KWIPC, Kaiser Wilhelm Institute for Chemistry and Electrochemisty, today the Fritz Haber Institute of the Max-Planck Society), and Max Volmer, director of the Physical Chemistry Institute at the Berlin Technische Hochschule (Technical University of Berlin), who all had made a pact that whoever first made contact with the Soviets would speak for the rest.^[92] Before the end of World War II, Thiessen, a member of the Nazi Party, had Communist contacts.^[93] On 27 April 1945, Thiessen arrived at von Ardenne's institute in an armored vehicle with a major of the Soviet Army, who was also a leading Soviet chemist, and they issued Ardenne a protective letter (Schutzbrief).^[94]

Comparison of the Manhattan Project and the Uranverein

The joint American, British, and Canadian Manhattan Project developed the uranium and plutonium atomic bombs, which helped bring an end to hostilities with Japan during World War II. Its success is attributable to meeting all four of the following conditions:^[95]

1. A strong initial drive, by a small group of scientists, to launch the project.
2. Unconditional government support from a certain point in time.
3. Essentially unlimited manpower and industrial resources.
4. A concentration of brilliant scientists devoted to the project.

Even with all four of these conditions in place the Manhattan Project succeeded only after the war in Europe had been brought to a conclusion. Mutual distrust existed between the German government and some scientists.^[96][97]
For the Manhattan Project, the second condition was met on 9 October 1941 or shortly thereafter. Germany fell short of what was required to make an atomic bomb.^{[98][99][100][101]} Significant here is that by the end of 1941 it was already apparent that the German nuclear energy project would not make a decisive contribution to ending the German war effort in the near term, and control of the project was relinquished by the Heereswaffenamt (HWA, Army Ordnance Office) to the Reichsforschungsrat (RFR, Reich Research Council) in July 1942.
Concerning condition three, the needs in materiel and manpower for a large-scale project necessary for the separation of isotopes for a uranium-based bomb and heavy water production for reactors for a plutonium-based bomb may have been possible in the early years of the war.^{[citation needed]}
As to condition four, the high priority allocated to the Manhattan Project allowed for the recruitment and concentration of capable scientists on the project. In Germany, on the other hand, a great many young scientists and technicians who would have been of great use to such a project were conscripted into the German armed forces, while others had fled the country before the war due to antisemitism and political persecution.^[102]
Whereas Enrico Fermi, a scientific Manhattan leader, had an "unique double aptitude for theoretical and experimental work" in the 20th century^[103], the successes at Leipzig until 1942 resulted from the cooperation between the theoretical physicist Werner Heisenberg and the experimentalist Robert Döpel. Most important was their experimental proof of an effective neutron increase in April 1942.^[104][105] At the end of July of the same year, the group around Fermi also succeeded in the neutron increase within a reactor-like arrangement.
In June 1942, Döpels "Uran-Maschine" was destroyed by a chemical explosion introduced by hydrogen^[106], which finished the work on this topic at Leipzig. Thereafter, despite increased expenditures the Berlin groups and their extern branches didn't succeed in getting a reactor critical until the end of World War II. However, this was realized by the Fermi group in December 1942, so that the German advantage was definitively lost, even with respect to research on energy production.

Recent developments

A book by Rainer Karlsch, Hitlers Bombe, published in 2005, alleged that Diebner's team conducted the first successful nuclear weapon test of some type (employing hollow charges for ignition) of nuclear-related device in Ohrdruf, Thuringia on 4 March 1945.^[107] However, Karlsch has been criticized for displaying "a catastrophic lack of understanding of physics" by physicist Michael Schaaf, who is himself the author of an earlier book about Nazi atomic research, while Karlsch himself has acknowledged that he lacked absolute proof for the claims made in his book.^[108]
A similar project was described in David Irving's 1967 book The Virus House, where it was claimed that some of Diebner's researchers had unsuccessfully attempted to produce fusion using conventional explosives and heavy paraffin as a deuterium carrier. Irving also describes a further experiment in 1943 carried out by Trinks and Sachsse, which used a hollow sphere of silver filled with deuterium, imploded by conventional explosives. Again it was unsuccessful, no trace of radioactivity being produced.^[109]
Science historian Mark Walker also published his analysis in 2005,^[110] and in 2005 Karlsch and Walker published an article on the controversial historical evidence, briefly referenced in the article.^[111] The Physikalisch-Technische Bundesanstalt (PTB, Federal Physical and Technical Institute) tested soil samples in the area of the alleged test, and in 2006 it issued its results: keinen Befund (nothing found).^[112] Karlsch published a follow-on book with Heinko Petermann to elaborate on issues raised in his first book.^[113]