Manhattan project

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Manhattan Project (USA)
Hanford Site, Richland, Washington
Hanford Site ,
Oak Ridge National Laboratory, Oak Ridge, Tennessee
Oak Ridge National Laboratory ,
Oak Ridge,
Trinity Test, White Sands Missile Range, New Mexico
Trinity Test ,
White Sands Missile Range,
New Mexico
Some locations of the Manhattan Project
General Leslie R. Groves and Robert Oppenheimer about 1942
First atomic bomb test "Trinity" 1945

The Manhattan Project (after the code name Manhattan Engineer District ) was a military research project, in which from 1942 all activities of the United States during the Second World War for the development and construction of an atom bomb - that is, the military utilization of the 1938 by Otto Hahn and Fritz Straßmann discovered nuclear fission - carried out under the military direction of General Leslie R. Groves . The research on the Manhattan Project was led by the physicist J. Robert Oppenheimer . More than 150,000 people worked for the project in the strictest of secrecy, directly or indirectly . By the end of 1945, the cost was $ 1.9 billion. British and Canadian scientists, who had their own nuclear weapons project under the code name Tube Alloys , cooperated with US researchers from 1943 (the Quebec Agreement ).

Projects from other countries

Research and development work on nuclear technology was undertaken during the same period in the Soviet Union by Igor Kurchatov as part of the Soviet atomic bomb project . In Germany, a group of physicists led by Werner Heisenberg was working on the uranium project . In Japan there was a nuclear weapons program headed by Yoshio Nishina . Because of the military secrecy, the scientists involved had no knowledge, but at most assumptions about the progress of the other programs and the USA.


In the years between the First and the Second World War in the United States, the scientific superiority rose in the field of nuclear physics . In addition to American physicists, the work of European immigrants also contributed to this . Until the beginning of the Second World War, they developed the experimental basis of nuclear physics with the cyclotron , the Van de Graaff accelerator and the artificial production of radioisotopes .

One of the most important scientists , Enrico Fermi , recalls the beginnings of the project in a speech he gave in 1954:

“I can still vividly remember the first month, January 1939, when I started to work in the Pupin laboratories because things started to develop very quickly at that time. Back then, Niels Bohr was lecturing at Princeton University , and one evening Willis Lamb came back excited and said that Bohr had made big news. It was the discovery of nuclear fission and an overview of what the discovery meant. A little later that month there was a meeting in Washington, DC , where the potential importance of the new phenomenon of fission was discussed semi-seriously for the first time as a potential source of nuclear energy . "

The refugee Hungarian scientists Leó Szilárd , Edward Teller and Eugene Wigner believed that nuclear fission could be used by the Germans to build bombs. They therefore convinced Germany's most famous physicist, Albert Einstein , to warn US President Franklin D. Roosevelt in a letter. In view of the intelligence reports about the German efforts and perhaps also because of Einstein's letter of August 2, 1939, it was decided to accelerate the development of an atomic bomb.

Under the supervision of Lyman Briggs , head of the National Bureau of Standards , a small research program began in 1939 at the Naval Research Laboratory in Washington. The physicist Philip Abelson worked there on the isotope separation of uranium . The Italian nuclear physicist Enrico Fermi at Columbia University built the prototype of a nuclear reactor out of natural uranium and graphite from initial research funding of 6,000 US dollars .

It was not until 1940, on the initiative of Vannevar Bush , director of the Carnegie Institution of Washington , that the United States began pooling scientific resources in support of the war effort. New laboratories emerged, including the radiation laboratory at the Massachusetts Institute of Technology , which played an important role in the development of radar , and the underwater sound laboratory in San Diego , where sonar was further developed.

The National Defense Research Council took over the uranium project , as Briggs' research program was known until then. In 1940, Bush and Roosevelt created the Office of Scientific Research and Development to accelerate research.


Until the summer of 1941 the project made little progress. That only changed with the calculations by Otto Frisch and Rudolf Peierls from Birmingham , UK , which showed that the explosive force of a very small amount of the fissile uranium isotope 235 U corresponds to the equivalent of several thousand tons of TNT . Concerned about the supposed progress in nuclear research in the Third Reich, the two had written a secret memorandum in March 1940 in which they called for more research in this area.

The National Academy of Sciences proposed extensive efforts to build nuclear weapons , whereupon Roosevelt formed the S-1 committee to direct the action. The decision was made on December 6, 1941, the day before Japan's attack on Pearl Harbor .

When the United States entered World War II in December 1941, there were several projects exploring the isotopic separation of uranium, the production of plutonium, and the feasibility of nuclear explosions. At the Metallurgical Laboratory of the University of Chicago , the Radiation Laboratory of the University of California and Columbia University , efforts to produce weapons-grade material from uranium have been intensified. In 1942, the first man-made nuclear reactor ever to become critical , Chicago Pile 1 , was built using metallic natural uranium fuel. The uranium ore came from the Shinkolobwe mine in the Congo and was supplied by the Belgian Union Minière du Haut Katanga . Because of its colonies , Belgium was one of the few countries with a substantial supply of uranium ore, making it the main supplier to the United States. This trade relationship later resulted in Belgium gaining access to nuclear technology for civil purposes (see Nuclear Energy in Belgium ).

At the beginning of 1942, the construction of large plants began: on the one hand, the first calutrons for uranium isotope separation - Site X of the project, today's Oak Ridge National Laboratory , in Tennessee - and, on the other hand, for plutonium production Site W , the Hanford plant near Richland , Washington.

In the spring of 1942, at the suggestion of Nobel laureate in physics Arthur Holly Compton , Robert Oppenheimer and Robert Serber from the University of Illinois did research on the problem of neutron diffusion (how neutrons behave in a chain reaction ) and hydrodynamics (how an explosion caused by a chain reaction behaves can). In order to have his research work and the general theory of the fission reactions appraised, Oppenheimer organized a "research summer" in June 1942 at the University of California at Berkeley . The participants Hans Bethe , John H. van Vleck , Edward Teller , Felix Bloch , Richard C. Tolman and Emil Konopinski came to the conclusion that a nuclear fission-based bomb was possible and assumed that a chain reaction that was critical for a self-sustaining chain reaction Mass must be present so that the neutrons emitted by the fission can split sufficiently another 235 U atoms. The difficulty lay in the targeted triggering of the chain reaction. This can be achieved either by the technically simpler “shooting” of two subcritical parts made of highly enriched uranium (“gun type”) or by compressing a subcritical nuclear fuel mass using a surrounding hollow charge made of conventional explosives (“implosion type”).

Also Victor Weisskopf took part in the project.

Teller saw an additional possibility: He suspected that a much more powerful super bomb could be built by covering the fission bomb with deuterium and tritium . The idea was based on Bethe's pre-war studies of energy production in stars . If the explosion wave of the fission bomb expanded through the mixture of the deuterium and tritium nuclei, these would thereby be fused; the process of nuclear fusion would release considerably more energy than nuclear fission. Bethe was skeptical and repeatedly rejected the sketches that Teller made for the super bomb. Teller suspected that his super bomb had the potential to ignite the atmosphere. Even after Bethe theoretically proved that this could not happen, there were faint doubts. In spite of this, Teller pushed the attempts to do so.

The results of Oppenheimer's summer conferences formed the theoretical basis for building the atomic bomb. This was one of the main tasks in 1943 as Site Y , founded in Los Alamos Laboratory . Serber later named the conferences The Los Alamos Primer (LA-1). It was on them that the concept of the hydrogen bomb , which took shape in the post-war period , was also developed. Rarely has a physics conference had such significance for the future of mankind.

With the prospect of a long war, a group of theoretical physicists around Robert Oppenheimer met in Berkeley in the summer of 1942 to determine plans for the development and design of a nuclear weapon. Fundamental questions about the properties of fast neutrons remained open. Physicist John H. Manley of the University of Chicago's Metallurgical Laboratory coordinated research groups for Oppenheimer across the country to answer this question.

Measurements of the interactions of fast neutrons with other materials inside a bomb were of great importance. The number of neutrons produced in the fission process of uranium and plutonium had to be known, and the substance surrounding the bomb had to have the property of reflecting or scattering these neutrons back into the bomb in order to increase the energy of the bomb. Therefore, the reflection properties of various materials had to be determined.

In order to be able to estimate the explosive power of a bomb, many other results from nuclear research were required. The particle accelerators required to produce fast neutrons were also extremely rare at the time. In September 1942, the difficulties in coordinating research facilities scattered across the country indicated the need for a central laboratory for nuclear weapons research. In addition, there was a great need for facilities for the production of 235 U and plutonium on a larger scale.

Manhattan District and Los Alamos

Trinity explosion

In the summer of 1942, a noticeable increase in deuterium production at the Norsk Hydro plant in Germany-occupied Norway was noted.

Vannevar Bush , President of the Office of Scientific Research and Development ( Office of Scientific Research and Development , OSRD) and James Bryant Conant , chairman of the National Defense and Research Committee ( National Defense Research Committee were NDRC), a subdivision of OSRD, In June 1942, the main political responsible for the implementation of President Roosevelt's decision to convert the previously existing scientific project of an Atomic Energy Development Program (OSRD) into a military project for the development of the most powerful nuclear weapons. Under Lieutenant General Brehon B. Somervell and Major General Wilhelm D. Styer , Brigadier General Leslie R. Groves was commissioned on September 16, 1942 with the main "military" management of this weapons project. Groves is named after the location of James C. Marshall's headquarters from New York City in Manhattan Engineer District (MED) to which was later shortened called Manhattan Project.

Within a week Groves solved the most urgent problems of the project and began in the highest secrecy in the mountains of New Mexico with the construction of Site Y , a research town near Los Alamos with extensive laboratory facilities and workshops. Robert Oppenheimer headed the facility as head of the nuclear weapons research project called the Trinity Project . Many physicists and technicians were concentrated in Los Alamos in the following months and together with the other research institutions over 100,000 people worked temporarily on the Manhattan Project. The total cost was about $ 2 billion. Converted to 2012, this corresponds to purchasing power of around 25.8 billion US dollars.

At the beginning of 1945, when it was more or less certain what the bombs would look like, the Alberta project was launched in March 1945 . This group of the Manhattan Project dealt with dropping the guns over the target. Project Alberta dealt with the radar height detonators, bombs and also with the conversions of the B-29 bombers as well as the training of the crews of the 509th Composite Group formed for this with dummy bombs.

About 250 km south of Los Alamos on the White Sands Proving Grounds , the Trinity test , the first successful detonation of an atomic bomb, took place on July 16, 1945 . The bomb used plutonium as a nuclear fuel and had an explosive force of 21  kilotons of TNT .

As the only civil observer with the approval of the American government, the journalist William L. Laurence participated as an eyewitness from the beginning of the project (see literature). President Harry S. Truman found out about the successful test at the Potsdam Conference and informed Josef Stalin that the USA had a new super weapon. Stalin was unimpressed, as he had long known what was being worked on in the USA through the spy ring made up of Klaus Fuchs , Theodore Hall , David Greenglass and Oscar Seborer († April 23, 2015, Moscow; exposed 2019). Preparations for a replica of the Mk.3 plutonium bomb and the B-29 bomber were already underway in the Soviet Union . Truman ordered the weapons to be made available for an operation over Japan as soon as possible, but did not place the final deployment order under his command. However, the responsible General Staff in the Pacific interpreted this to mean using the bombs as quickly as possible. By the day the Potsdam Conference ended, all the components of the bombs had arrived in Tinian. Truman learned of the drop on Hiroshima on the return trip to the USA.

Results of the Manhattan Project

Since the European Axis powers had meanwhile surrendered, the atomic bomb developed in the Manhattan Project was no longer used here.

President Roosevelt reportedly instructed Leslie Groves , the military director of the Manhattan Project, to prepare to drop an atomic bomb on Germany if it got through to Germany before the end of the war.

"[Beginning of February 1945] Mr Roosevelt informed me that if the European war was not over before we had our first bombs he wanted us to be ready to drop them on Germany."

The US Department of Defense is said to have already selected the industrial centers Ludwigshafen am Rhein and Mannheim as possible targets; other circles would have preferred Berlin as a possible location for the atomic bomb in Europe.

The only military use of atomic bombs to date took place over Japanese cities soon after. On August 6, 1945, the bomb called Little Boy , which consisted mainly of 235 U , was dropped over Hiroshima . Three days later, on August 9, over was Nagasaki The Fat Man dropped bomb called, mostly from 239 Pu was. According to different estimates, between 90,000 and 180,000 people in Hiroshima and between 50,000 and 100,000 people in Nagasaki, mostly Japanese civilians, died during the explosions and afterwards from their consequences ( radiation sickness ). A few days later, the Japanese Empire capitulated . Whether the use of the atomic bombs alone was decisive for this decision remains controversial.

There had been a heated discussion about the use of the bombs. Some researchers advocated demonstrating the weapon’s destructive power first over uninhabited areas in order to induce Japan to surrender; the military and President Harry S. Truman were for military-practical use.

Nuclear waste disposal

The uranium fuel for Fermis Chicago Pile -1 was made from uranium ore by G. Mallinckrodt & Co in St. Louis . The resulting radioactive waste is stored, more or less kept secret, in a landfill there . There have been protests from residents to this day against this landfill operated by the waste management company Republic Services , as the area has an increased cancer rate .

See also


  • Stephane Groueff: Project without mercy - the adventure of the American nuclear industry. Bertelsmann, Gütersloh 1968.
  • Leslie R. Groves : Now it can be told - The story of the Manhattan Project. Introduction by Edward Teller. Da Capo Press, New York 1962, 1983. ISBN 0-306-80189-2 .
  • Ruth H. Howes; Caroline L. Herzenberg: Their Day in the Sun: Women of the Manhattan Project. Temple University Press, Philadelphia, Pennsylvania 1999.
  • Robert Jungk : Brighter than a thousand suns. The fate of atomic researchers. Scherz & Goverts, Stuttgart 1956, Rowohlt, Reinbek 1986, ISBN 3-499-16629-1 .
  • William L. Laurence : The History of the Atomic Bomb: Twilight Over Point Zero. List, Munich 1952.
  • Robert S. Norris: Racing for the bomb. General Leslie R. Groves, The Manhattan projects indispensable men. Steerforth Press, South Royalton 2002, ISBN 1-58642-039-9 .
  • Richard Rhodes : The Atomic Bomb or The Story of the 8th Day of Creation. Greno, Nordlingen, 1988; Volk und Welt, Berlin, 1990, ISBN 3-353-00717-2 .
  • Cay Rademacher : Attack on Asia-Hiroshima Geo Epoch (Issue No. 17) 04/05 End of the war 1945-Finale of the world fire p. 112–130.



Web links

Commons : Manhattan Project  - collection of images, videos and audio files

Individual evidence

  1. ^ Bruce Cameron Reed: The history and science of the Manhattan Project. Springer, Berlin 2014, ISBN 978-3-642-40296-8 , p. 1 @ google books
  2. Rich Tenorio: "Historians uncover fourth Soviet spy who stole US atomic secrets in WWII" dated December 2, 2019
  3. ^ Groves, Leslie (1962). Now it Can be Told: The Story of the Manhattan Project. New York: Harper & Row. ISBN 0-306-70738-1 . OCLC 537684 ; P. 184.
  4. Frequently Asked Questions # 1 ( English ) Radiation Effects Research Foundation . Archived from the original on September 19, 2007. Retrieved on August 18, 2019.
  5. Chapter II: The Effects of the Atomic Bombings ( English ) In: United States Strategic Bombing Survey . Originally by USGPO ; stored on ibiblio .org. 1946. Retrieved June 3, 2011.
  6. Der Standard , October 2017 [1]
  7. The review of the film by N. Genzlinger in the New York Times indicates that the threat to the world community through the use of weapons also exists today. Genzlinger, Neil: "'The Bomb' Helps Return Nukes to the TV Spotlight". New York Times July 27, 2015
  8. Day One in the Internet Movie Database (English)