The Alsos Mission was an organized effort by a team of British and United States military, scientific, and intelligence personnel to discover enemy scientific developments during
World War II
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
. Its chief focus was to investigate the progress that
Germany was making in the area of nuclear technology, and to seize any German nuclear resources that would either be of use to the
Manhattan Project
The Manhattan Project was a research and development program undertaken during World War II to produce the first nuclear weapons. It was led by the United States in collaboration with the United Kingdom and Canada.
From 1942 to 1946, the ...
or worth denying to the
Soviet Union
The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...
. It also investigated German
chemical
A chemical substance is a unique form of matter with constant chemical composition and characteristic properties. Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be combin ...
and
biological weapon
Biological agents, also known as biological weapons or bioweapons, are pathogens used as weapons. In addition to these living or replicating pathogens, toxins and Toxin#Biotoxins, biotoxins are also included among the bio-agents. More than 1,2 ...
development and the means to deliver them, and any other advanced Axis technology it was able to get information about in the course of the other investigations (such as the
V-2 rocket
The V2 (), with the technical name ''Aggregat (rocket family), Aggregat-4'' (A4), was the world's first long-range missile guidance, guided ballistic missile. The missile, powered by a liquid-propellant rocket engine, was developed during the S ...
program).
The Alsos Mission was created after the September 1943
Allied invasion of Italy
The Allied invasion of Italy was the Allies of World War II, Allied Amphibious warfare, amphibious landing on mainland Italy that took place from 3 September 1943, during the Italian campaign (World War II), Italian campaign of World War II. T ...
as part of the
Manhattan Project
The Manhattan Project was a research and development program undertaken during World War II to produce the first nuclear weapons. It was led by the United States in collaboration with the United Kingdom and Canada.
From 1942 to 1946, the ...
's mission to coordinate foreign intelligence related to enemy nuclear activity. The team had a twofold assignment: search for personnel, records, material, and sites to evaluate the above programs and prevent their capture by the
Soviet Union
The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...
. Alsos personnel followed close behind the front lines in Italy, France, and Germany, occasionally crossing into enemy-held territory to secure valuable resources before they could be destroyed or scientists escape or fall into rival hands.
The Alsos Mission was commanded by Colonel
Boris Pash, a former Manhattan Project security officer, with
Samuel Goudsmit as chief scientific advisor. It was jointly staffed by the
Office of Naval Intelligence
The Office of Naval Intelligence (ONI) is the military intelligence agency of the United States Navy. Established in 1882 primarily to advance the Navy's modernization efforts, it is the oldest member of the U.S. Intelligence Community and serv ...
(ONI), the
Office of Scientific Research and Development
The Office of Scientific Research and Development (OSRD) was an agency of the United States federal government created to coordinate scientific research for military purposes during World War II. Arrangements were made for its creation during May ...
(OSRD), the Manhattan Project, and
Army Intelligence (G-2), with field assistance from
combat engineers
A combat engineer (also called pioneer or sapper) is a type of soldier who performs military engineering tasks in support of land forces combat operations. Combat engineers perform a variety of military engineering, Tunnel warfare, tunnel and l ...
assigned to specific task forces.
Alsos teams were successful in locating and removing a substantial portion of the German research effort's surviving records and equipment. They also took most of the senior German research personnel into custody, including
Otto Hahn
Otto Hahn (; 8 March 1879 – 28 July 1968) was a German chemist who was a pioneer in the field of radiochemistry. He is referred to as the father of nuclear chemistry and discoverer of nuclear fission, the science behind nuclear reactors and ...
,
Max von Laue
Max Theodor Felix von Laue (; 9 October 1879 – 24 April 1960) was a German physicist who received the Nobel Prize in Physics in 1914 "for his discovery of the X-ray diffraction, diffraction of X-rays by crystals".
In addition to his scientifi ...
,
Werner Heisenberg
Werner Karl Heisenberg (; ; 5 December 1901 – 1 February 1976) was a German theoretical physicist, one of the main pioneers of the theory of quantum mechanics and a principal scientist in the German nuclear program during World War II.
He pub ...
and
Carl Friedrich von Weizsäcker. By November-December 1944, they had concluded that there was no threat of a German atomic bomb, and that the German nuclear program had only reached an experimental phase, not a production phase. After the defeat of Japan, an Alsos mission was sent in to evaluate its nuclear program as well.
Origin
The
Manhattan Project
The Manhattan Project was a research and development program undertaken during World War II to produce the first nuclear weapons. It was led by the United States in collaboration with the United Kingdom and Canada.
From 1942 to 1946, the ...
was the Allied nuclear weapons research-and-development program, operated during and immediately after World War II, led by the United States with contributions principally from the United Kingdom and Canada.
Brigadier General Leslie Groves
Leslie Richard Groves Jr. (17 August 1896 – 13 July 1970) was a United States Army Corps of Engineers officer who oversaw the construction of the Pentagon and directed the Manhattan Project, a Classified information#Top_Secret_(TS), top sec ...
of the
U.S. Army Corps of Engineers became its director in September 1942. The project operated under a tight blanket of security lest its discovery induce
Axis powers
The Axis powers, originally called the Rome–Berlin Axis and also Rome–Berlin–Tokyo Axis, was the military coalition which initiated World War II and fought against the Allies of World War II, Allies. Its principal members were Nazi Ge ...
, particularly Germany, to accelerate their own nuclear projects or to undertake covert operations against the project.
Allied work on
nuclear fission
Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radioactiv ...
had been motivated by scientists, many of whom were refugees from
Nazi Germany
Nazi Germany, officially known as the German Reich and later the Greater German Reich, was the German Reich, German state between 1933 and 1945, when Adolf Hitler and the Nazi Party controlled the country, transforming it into a Totalit ...
, who feared a German atomic bomb program was underway. The discovery of fission had taken place largely in
Otto Hahn
Otto Hahn (; 8 March 1879 – 28 July 1968) was a German chemist who was a pioneer in the field of radiochemistry. He is referred to as the father of nuclear chemistry and discoverer of nuclear fission, the science behind nuclear reactors and ...
's
Berlin
Berlin ( ; ) is the Capital of Germany, capital and largest city of Germany, by both area and List of cities in Germany by population, population. With 3.7 million inhabitants, it has the List of cities in the European Union by population withi ...
laboratory, and many scientists in the United States held the work of German scientists, especially
Werner Heisenberg
Werner Karl Heisenberg (; ; 5 December 1901 – 1 February 1976) was a German theoretical physicist, one of the main pioneers of the theory of quantum mechanics and a principal scientist in the German nuclear program during World War II.
He pub ...
, in high regard. Fear that they were in a "race" for the atomic bomb was one of the main reasons for the establishment of the Manhattan Project and acceleration of the Allied effort. The
Chancellor of Germany
The chancellor of Germany, officially the federal chancellor of the Federal Republic of Germany, is the head of the federal Cabinet of Germany, government of Germany. The chancellor is the chief executive of the Federal Government of Germany, ...
,
Adolf Hitler
Adolf Hitler (20 April 1889 – 30 April 1945) was an Austrian-born German politician who was the dictator of Nazi Germany from 1933 until Death of Adolf Hitler, his suicide in 1945. Adolf Hitler's rise to power, He rose to power as the lea ...
, frequently claimed that Germany was developing secret weapons, and it was feared that these might include nuclear weapons. Reports of German nuclear activity were taken seriously. At the instigation of the Manhattan Project, Norwegian saboteurs and Allied bombers
attacked heavy-water infrastructure in German-occupied Norway in late 1942 and early 1943.
Following the September 1943
Allied invasion of Italy
The Allied invasion of Italy was the Allies of World War II, Allied Amphibious warfare, amphibious landing on mainland Italy that took place from 3 September 1943, during the Italian campaign (World War II), Italian campaign of World War II. T ...
, Brigadier General
Wilhelm D. Styer, Chief of Staff of
Army Service Forces, was concerned that intelligence activities related to foreign nuclear energy programs were not being properly coordinated. He feared that important items might be overlooked unless those responsible were properly briefed, yet at the same time wished to minimize the number of personnel with access to such secret information. Having the Manhattan Project itself take over responsibility for coordinating these efforts would address both these concerns. Accordingly, he approached Groves on behalf of General
George Marshall
George Catlett Marshall Jr. (31 December 1880 – 16 October 1959) was an American army officer and statesman. He rose through the United States Army to become Chief of Staff of the United States Army, Chief of Staff of the U.S. Army under pres ...
, the
Chief of Staff of the Army, with that recommendation.
In response, Groves created the ''Alsos Mission'', a small team jointly staffed by the
Office of Naval Intelligence
The Office of Naval Intelligence (ONI) is the military intelligence agency of the United States Navy. Established in 1882 primarily to advance the Navy's modernization efforts, it is the oldest member of the U.S. Intelligence Community and serv ...
(ONI), the
Office of Scientific Research and Development
The Office of Scientific Research and Development (OSRD) was an agency of the United States federal government created to coordinate scientific research for military purposes during World War II. Arrangements were made for its creation during May ...
(OSRD), the Manhattan Project, and Army Intelligence (G-2). Its assignment was to investigate enemy scientific developments, including nuclear weapons research. Groves was not pleased with the codename (derived from , the Greek word for "
grove"), but decided that changing it would only draw unwanted attention.
The Chief of Army Intelligence,
Major General George V. Strong, appointed
Lieutenant Colonel Boris Pash to command the unit. Pash had served as the head of the Counter Intelligence Branch of the
Western Defense Command
Western Defense Command (WDC) was established on 17 March 1941 as the command formation of the United States Army responsible for coordinating the defense of the West Coast of the United States, Pacific Coast region of the United States during Wo ...
, where he had investigated suspected Soviet espionage at the
Radiation Laboratory at Berkeley. Pash's command comprised his executive officer Captain Wayne B. Stanard, four
Counter Intelligence Corps (CIC) agents, four interpreters, and four scientists: Dr. James B. Fisk from the
Bell Telephone Company
The Bell Telephone Company was the initial corporate entity from which the Bell System originated to build a continental conglomerate and monopoly in telecommunication services in the United States and Canada.
The company was organized in Bost ...
, Dr.
John R. Johnson from
Cornell University
Cornell University is a Private university, private Ivy League research university based in Ithaca, New York, United States. The university was co-founded by American philanthropist Ezra Cornell and historian and educator Andrew Dickson W ...
, Commander Bruce Old from the Office of Naval Intelligence (ONI) and the
Massachusetts Institute of Technology
The Massachusetts Institute of Technology (MIT) is a Private university, private research university in Cambridge, Massachusetts, United States. Established in 1861, MIT has played a significant role in the development of many areas of moder ...
(MIT), and Major
William Allis, originally from MIT although then serving on the
War Department scientific staff.
The Manhattan Project intelligence staff believed that the
Japanese atomic program was not far advanced because Japan had little access to
uranium ore
Uranium ore deposits are economically recoverable concentrations of uranium within Earth's crust. Uranium is one of the most common Chemical element, elements in Earth's crust, being 40 times more common than silver and 500 times more common than ...
, the industrial effort required exceeded Japan's capacity, and, according to American physicists at the
University of California, Berkeley
The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a Public university, public Land-grant university, land-grant research university in Berkeley, California, United States. Founded in 1868 and named after t ...
, who knew the leading Japanese physicists personally, there were too few Japanese qualified to work in the area.
Italy
In December 1943, the Alsos Mission reached
Algiers
Algiers is the capital city of Algeria as well as the capital of the Algiers Province; it extends over many Communes of Algeria, communes without having its own separate governing body. With 2,988,145 residents in 2008Census 14 April 2008: Offi ...
, where Pash reported to the Chief of Staff at
Allied Force Headquarters (AFHQ), Major General
Walter B. Smith, and his British Chief of Intelligence,
Brigadier
Brigadier ( ) is a military rank, the seniority of which depends on the country. In some countries, it is a senior rank above colonel, equivalent to a brigadier general or commodore (rank), commodore, typically commanding a brigade of several t ...
Kenneth Strong. This was awkward as Pash's instructions were not to give the British information about the Alsos Mission, but it turned out that Strong was already fully aware of it. It was arranged that Pash would deal with Strong's American deputy, Colonel
Thomas E. Roderick. The Alsos Mission then moved on to Italy, where it was assigned to Major General
Kenyon A. Joyce's
Allied Control Commission
Following the termination of hostilities in World War II, the Allies were in control of the defeated Axis countries. Anticipating the defeat of Germany, Italy and Japan, they had already set up the European Advisory Commission and a proposed Far ...
. Pash met with
Marshal of Italy
Marshal of Italy () was a rank in the Royal Italian Army (''Regio Esercito''). Originally created in 1924 by Italian dictator Benito Mussolini
Benito Amilcare Andrea Mussolini (29 July 188328 April 1945) was an Italian politician and jo ...
Pietro Badoglio
Pietro Badoglio, 1st Duke of Addis Abeba, 1st Marquess of Sabotino ( , ; 28 September 1871 – 1 November 1956), was an Italian general during both World Wars and the first viceroy of Italian East Africa. With the fall of the Fascist regim ...
, the man who had negotiated Italy's surrender to the
Allies, and was now head of the Italian Provisional Military Government, who gave him a letter of introduction addressed to Italian civil and military authorities.
Alsos interviewed the Italian Minister for Communications, the Chief of Naval Ordnance, the staff of the Italian Naval Academy, and Italian scientists at the
University of Naples
The University of Naples Federico II (; , ) is a public university, public research university in Naples, Campania, Italy. Established in 1224 and named after its founder, Frederick II, Holy Roman Emperor, Frederick II, it is the oldest public, s ...
, and examined what captured technical documents could be found. There was little information about developments in northern Italy and Germany. The Alsos Mission was attached to Colonel George Smith's S-Force. Built around a
Royal Air Force
The Royal Air Force (RAF) is the Air force, air and space force of the United Kingdom, British Overseas Territories and Crown Dependencies. It was formed towards the end of the World War I, First World War on 1 April 1918, on the merger of t ...
ground reconnaissance squadron equipped with armored cars, this unit contained American, British, French, and Italian technical specialists of various kinds who would enter Rome on the heels of the advancing Allied forces. The expectation that Rome would soon be captured proved premature, and by March 1944 most of the Alsos Mission had returned to the United States. The Alsos Mission had gathered little of value about nuclear matters, but submitted detailed reports about German rockets and guided missiles.
Rome fell on 4 June 1944. When the news came that its fall was imminent, Pash was ordered from London to Italy. He flew back to Italy and entered the city with S-Force on 5 June. Pash took key scientists into custody and arranged for sites targeted by Alsos, including the
University of Rome and the ''
Consiglio Nazionale delle Ricerche
The National Research Council (Italian: ''Consiglio Nazionale delle Ricerche, CNR'') is the largest research council in Italy. As a public organisation, its remit is to support scientific and technological research. Its headquarters are in Rome. ...
'', to be secured. The Alsos Mission to Italy was reconstituted under the command of Pash's deputy, Major Richard C. Ham, and Johnson and Major
Robert R. Furman were sent from the United States to join him. They reached Rome on 19 June, and over the next weeks interviewed scientists including
Edoardo Amaldi
Edoardo Amaldi (5 September 1908 – 5 December 1989) was an Italian physicist. He coined the term "neutrino" in conversations with Enrico Fermi distinguishing it from the heavier "neutron". He has been described as "one of the leading nuclear p ...
,
Gian-Carlo Wick
Gian Carlo Wick (15 October 1909 – 20 April 1992) was an Italian theoretical physicist who made important contributions to quantum field theory. The Wick rotation, Wick contraction, Wick's theorem, and the Wick product are named after him. , and
Francesco Giordani. The picture that the Alsos Mission built up indicated that the German effort was not far advanced.
Western Europe
Britain
In December 1943, Groves sent Furman to Britain to discuss the establishment of a London Liaison Office for the Manhattan Project with the British government, and to confer over coordinating the intelligence effort.
Lieutenant Commander Eric Welsh, the head of the Norwegian Section of
MI6
The Secret Intelligence Service (SIS), commonly known as MI6 ( Military Intelligence, Section 6), is the foreign intelligence service of the United Kingdom, tasked mainly with the covert overseas collection and analysis of human intelligenc ...
, was unimpressed with Furman's grasp of the subject matter. Groves selected the head of the Manhattan District's security activities, Captain Horace K. Calvert, as head of the London Liaison Office, with the title of Assistant Military Attaché. Working in cooperation with Welsh and
Michael Perrin from
Tube Alloys
Tube Alloys was the research and development programme authorised by the United Kingdom, with participation from Canada, to develop nuclear weapons during the Second World War. Starting before the Manhattan Project in the United States, the Bri ...
, the London Liaison Office consisted of Calvert, Captain George B. Davis, two
Women's Army Corps
The Women's Army Corps (WAC; ) was the women's branch of the United States Army. It was created as an auxiliary unit, the Women's Army Auxiliary Corps (WAAC), on 15 May 1942, and converted to an active duty status in the Army of the United S ...
clerks and three CIC agents.

The Liaison Office interviewed European refugee scientists and studied German physics journals. It compiled lists of German scientists of interest and possible locations of nuclear research and industrial facilities, and the mining and stockpiling of
uranium
Uranium is a chemical element; it has chemical symbol, symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Ura ...
and
thorium
Thorium is a chemical element; it has symbol Th and atomic number 90. Thorium is a weakly radioactive light silver metal which tarnishes olive grey when it is exposed to air, forming thorium dioxide; it is moderately soft, malleable, and ha ...
ores. Little thorium was available in Germany or
German-occupied Europe
German-occupied Europe, or Nazi-occupied Europe, refers to the sovereign countries of Europe which were wholly or partly military occupation, militarily occupied and civil-occupied, including puppet states, by the (armed forces) and the governmen ...
, and attention soon centered on the mines at
Joachimsthal in
Sudetenland
The Sudetenland ( , ; Czech and ) is a German name for the northern, southern, and western areas of former Czechoslovakia which were inhabited primarily by Sudeten Germans. These German speakers had predominated in the border districts of Bohe ...
(the German-annexed part of
Czechoslovakia
Czechoslovakia ( ; Czech language, Czech and , ''Česko-Slovensko'') was a landlocked country in Central Europe, created in 1918, when it declared its independence from Austria-Hungary. In 1938, after the Munich Agreement, the Sudetenland beca ...
).
Aerial reconnaissance
Aerial reconnaissance is reconnaissance for a military or Strategy, strategic purpose that is conducted using reconnaissance aircraft. The role of reconnaissance can fulfil a variety of requirements including Artillery observer, artillery spott ...
was carried out periodically, and production was measured by assessing the size of the piles of
tailings
In mining, tailings or tails are the materials left over after the process of separating the valuable fraction from the uneconomic fraction (gangue) of an ore. Tailings are different from overburden, which is the waste rock or other material ...
.
Groves warned General
Dwight D. Eisenhower
Dwight David "Ike" Eisenhower (born David Dwight Eisenhower; October 14, 1890 – March 28, 1969) was the 34th president of the United States, serving from 1953 to 1961. During World War II, he was Supreme Commander of the Allied Expeditionar ...
of the possibility that the Germans might disrupt the
Normandy landings
The Normandy landings were the landing operations and associated airborne operations on 6 June 1944 of the Allies of World War II, Allied invasion of Normandy in Operation Overlord during the Second World War. Codenamed Operation Neptune and ...
with radioactive poisons, and sent Major Arthur V. Peterson to brief his chief of staff, Lieutenant General
Walter B. Smith. Under the codename
Operation Peppermint, special equipment was prepared and
Chemical Warfare Service
The Chemical Corps is the branch of the United States Army tasked with defending against and using chemical weapon, chemical, biological agent, biological, radiological weapon, radiological, and nuclear weapon, nuclear (Chemical, biological, r ...
teams were trained in its use. The British forces made similar preparations for their beaches. The precautions were unnecessary.
Meanwhile, the new head of G-2, Major General
Clayton L. Bissell
Major general (United States), Major General Clayton Lawrence Bissell (July 29, 1896 – December 24, 1972) was an air officer in the United States Army and United States Army Air Forces during World War I and World War II.
World War I service
...
, at the urging of Groves and Furman, decided to create a new, even larger Alsos Mission for western Europe in March 1944. Pash assumed command of the new unit upon its official creation by the
Secretary of War
The secretary of war was a member of the U.S. president's Cabinet, beginning with George Washington's administration. A similar position, called either "Secretary at War" or "Secretary of War", had been appointed to serve the Congress of the ...
,
Henry L. Stimson, on 4 April. The military staff for the new mission were selected by Bissell on Pash's advice. Lieutenant Colonel
George R. Eckman became the deputy commander. Captain
Henry A. Schade was appointed as the head of the naval contingent. Groves and
Vannevar Bush
Vannevar Bush ( ; March 11, 1890 – June 28, 1974) was an American engineer, inventor and science administrator, who during World War II, World War II headed the U.S. Office of Scientific Research and Development (OSRD), through which almo ...
, the head of OSRD, selected the scientific staff, and appointed
Samuel Goudsmit, a
University of Michigan
The University of Michigan (U-M, U of M, or Michigan) is a public university, public research university in Ann Arbor, Michigan, United States. Founded in 1817, it is the oldest institution of higher education in the state. The University of Mi ...
physicist with a good command of several western European languages, as its head. Goudsmit had not been working on the Manhattan Project, and therefore could not reveal any of its secrets if captured. The British considered creating their own rival mission, but in the end agreed to participate as a junior partner. Three Dutch and one Norwegian officer also served with the Alsos Mission. By the end of August it had seven officers and 33 scientists.
France
On 5 August, Pash received a secret message from Washington, D.C., reporting that the French physicist
Frédéric Joliot-Curie
Jean Frédéric Joliot-Curie (; ; 19 March 1900 – 14 August 1958) was a French chemist and physicist who received the 1935 Nobel Prize in Chemistry with his wife, Irène Joliot-Curie, for their discovery of induced radioactivity. They were t ...
had been sighted at his holiday home at L'Arcouest in
Brittany
Brittany ( ) is a peninsula, historical country and cultural area in the north-west of modern France, covering the western part of what was known as Armorica in Roman Gaul. It became an Kingdom of Brittany, independent kingdom and then a Duch ...
. Joliot-Curie was at the top of Alsos's wanted list, so Pash and CIC Special Agent Gerry Beatson set out to investigate in the wake of the advancing
U.S. Third Army. On 11 August they reached the homes of Joliot-Curie,
Francis Perrin, and
Pierre Auger in the L'Arcouest area. Pash and Beatson got there the morning of 17 August with Task Force A, and they were directed to Joliot-Curie's house, which had been emptied by the Germans. They searched the
University of Rennes
The University of Rennes (French: ''Université de Rennes'') is a public university, public research university located in Rennes, Upper Brittany, France. Originally founded in 1460, the university was split into two universities in 1970: Univers ...
and found some documents there on 21 August.

The rest of the advance party of the Alsos Mission moved to Normandy in August 1944, where it joined
T-Force
T-Force was the operational arm of a joint US Army–British Army mission to secure German scientific and industrial technology before it could be destroyed by retreating German forces or looters during the final stages of the Second World War a ...
, a similar formation to S-Force, at
Rambouillet
Rambouillet (, , ) is a Subprefectures in France, subprefecture of the Yvelines Departments of France, department in the Île-de-France Regions of France, region of France. It is located beyond the outskirts of Paris, southwest of its Kilometr ...
, where it was preparing for the
liberation of Paris. An Alsos Mission team including Pash and Calvert reached Joliot-Curie's house in the Paris suburbs on 24 August to find that he was not there, but at his laboratory at the
Collège de France
The (), formerly known as the or as the ''Collège impérial'' founded in 1530 by François I, is a higher education and research establishment () in France. It is located in Paris near La Sorbonne. The has been considered to be France's most ...
. The next day they reached the
Porte d'Orléans where they encountered troops of the French ''
2e Division Blindée'', who were engaged in liberating the city, and came under small arms fire from the German defenders. The Alsos Mission replied with their
M1 carbine
The M1 carbine (formally the United States carbine, caliber .30, M1) is a lightweight semi-automatic carbine chambered in the .30 carbine (7.62×33mm) cartridge that was issued to the U.S. military during World War II, the Korean War, and t ...
s and
Thompson submachine gun
The Thompson submachine gun (also known as the "Tommy gun", "Chicago typewriter", or "trench broom") is a blowback-operated, selective-fire submachine gun, invented and developed by Brigadier General John T. Thompson, a United States Arm ...
s as they made their way through the back streets to the college, where they found Joliot-Curie in his office.
Goudsmit interviewed Joliot-Curie in Paris on 27 August. Accompanied by Calvert, Joliot-Curie was flown to London where Perrin and Goudsmit interviewed him about the activities of German scientists. Joliot-Curie recalled visits to the College, which had a
cyclotron
A cyclotron is a type of particle accelerator invented by Ernest Lawrence in 1929–1930 at the University of California, Berkeley, and patented in 1932. Lawrence, Ernest O. ''Method and apparatus for the acceleration of ions'', filed: Januar ...
, by German scientists including
Erich Schumann, who had initiated the German nuclear project, and controlled it until it had been handed over to the ''
Reichsforschungsrat The Reichsforschungsrat ("Imperial Research Council") was created in Germany in 1936 under the Education Ministry for the purpose of centralized planning of all basic and applied research, with the exception of aeronautical research. It was reorgani ...
'' (National Research Council) in 1942; by
Abraham Esau
Robert Abraham Esau (7 June 1884 – 12 May 1955) was a German physicist.
After receipt of his doctorate from the University of Berlin, Esau worked at Telefunken, where he pioneered very high frequency (VHF) waves used in radar, radio, and tele ...
, who had been in charge of nuclear physics under the ''Reichsforschungsrat''; and by
Walter Gerlach, who had replaced him in January 1944. Other German physicists who had used the facilities included
Kurt Diebner,
Walther Bothe
Walther Wilhelm Georg Bothe (; 8 January 1891 – 8 February 1957) was a German physicist who shared the 1954 Nobel Prize in Physics with Max Born "for the coincidence method and his discoveries made therewith".
He served in the military durin ...
, and
Erich Bagge, all of whom were known to be associated with the German nuclear project.
Meanwhile, T-Force had moved into the
Petit Palais
The (; ) is an art museum in the 8th arrondissement of Paris, France.
Built for the Exposition Universelle (1900), 1900 Exposition Universelle ("universal exhibition"), it now houses the City of Paris Museum of Fine Arts (''Musée des beaux-arts ...
. The main body of the Alsos Mission soon followed, and the Mission opened an office at the
Place de l'Opéra
The Place de l'Opéra () is a square in the 9th arrondissement of Paris, 9th arrondissement of Paris, at the junction of the Boulevard des Italiens, Boulevard des Capucines, Avenue de l'Opéra, , , Rue de la Paix and . It was built at the same tim ...
. On 5 September, word was received that the British
21st Army Group
The 21st Army Group was a British headquarters formation formed during the Second World War. It controlled two field armies and other supporting units, consisting primarily of the British Second Army and the First Canadian Army. Established ...
was about to enter
Brussels
Brussels, officially the Brussels-Capital Region, (All text and all but one graphic show the English name as Brussels-Capital Region.) is a Communities, regions and language areas of Belgium#Regions, region of Belgium comprising #Municipalit ...
. There were two important Alsos Mission objectives in Belgium: the corporate headquarters of
Union Minière du Haut Katanga, the world's largest supplier of uranium ore, in
Antwerp
Antwerp (; ; ) is a City status in Belgium, city and a Municipalities of Belgium, municipality in the Flemish Region of Belgium. It is the capital and largest city of Antwerp Province, and the third-largest city in Belgium by area at , after ...
, and its uranium processing plant in
Olen. A six-man Alsos Mission team set out to secure them, led by Pash and the Assistant Chief of Staff, G-2, at
ETOUSA, Colonel
G. Bryan Conrad
G is the seventh letter of the Latin alphabet.
G may also refer to:
Places
* Gabon, international license plate code G
* Glasgow, UK postal code G
* Eastern Quebec, Canadian postal prefix G
* Melbourne Cricket Ground in Melbourne, Australia, ...
.
On reaching Brussels, they made contact with Lieutenant Colonel
David Strangeways, the commander of
R Force, who provided them with an escort of Royal Air Force armored vehicles. They entered Antwerp on 7 September and found the office of Union Minière. They discovered that over 1,000 tons of refined uranium had been sent to Germany, but about 150 tons still remained at Olen. They set out for Olen, where they located 68 tons, but another 80 tons were missing, having been shipped to France in 1940 ahead of the German invasion of Belgium. The capture of
Eindhoven
Eindhoven ( ; ) is a city and List of municipalities of the Netherlands, municipality of the Netherlands, located in the southern Provinces of the Netherlands, province of North Brabant, of which it is the largest municipality, and is also locat ...
by the
U.S. 101st Airborne Division allowed early access to another high priority target, the
Philips
Koninklijke Philips N.V. (), simply branded Philips, is a Dutch multinational health technology company that was founded in Eindhoven in 1891. Since 1997, its world headquarters have been situated in Amsterdam, though the Benelux headquarter ...
plant there. Brigadier
Edgar Williams, the 21st Army Group's Chief of Intelligence, facilitated the Alsos Mission's detour to Eindhoven, where it was able to interview Dutch scientists. Williams also furnished a detachment of
Royal Engineers
The Corps of Royal Engineers, usually called the Royal Engineers (RE), and commonly known as the ''Sappers'', is the engineering arm of the British Army. It provides military engineering and other technical support to the British Armed Forces ...
to transport and move the uranium from Olen. Groves had it shipped to England, and, ultimately, to the United States.

The Alsos Mission now attempted to recover the shipment that had been sent to France. Documentation was discovered that said that part of it had been sent to
Toulouse
Toulouse (, ; ; ) is a city in southern France, the Prefectures in France, prefecture of the Haute-Garonne department and of the Occitania (administrative region), Occitania region. The city is on the banks of the Garonne, River Garonne, from ...
. An Alsos Mission team under Pash's command reached Toulouse on 1 October and inspected a French Army arsenal. They used a
Geiger counter
A Geiger counter (, ; also known as a Geiger–Müller counter or G-M counter) is an electronic instrument for detecting and measuring ionizing radiation with the use of a Geiger–Müller tube. It is widely used in applications such as radiat ...
to find barrels containing 31 tons of the uranium from Belgium. Conrad persuaded Major General
Frank S. Ross to release the U.S. 3342nd Quartermaster Truck Company from the
Red Ball Express
The Red Ball Express was an American truck convoy system that supplied World War II allies, Allied forces moving through Europe after breaking out from the D-Day beaches in Normandy in the summer of 1944. To expedite cargo shipments to the fro ...
to retrieve the shipment. The barrels were collected and transported to
Marseille
Marseille (; ; see #Name, below) is a city in southern France, the Prefectures in France, prefecture of the Departments of France, department of Bouches-du-Rhône and of the Provence-Alpes-Côte d'Azur Regions of France, region. Situated in the ...
, where they were loaded on a ship bound for the United States. During the loading process a barrel fell into the water and had to be retrieved by a Navy diver. In Marseilles, the Alsos Mission detachment also met up with the detachment that had been sent to Italy, which now rejoined them. The remaining 49 tons of the original shipment to France were never found.
Information gathered in Rennes, Paris, and Eindhoven pointed to
Strasbourg
Strasbourg ( , ; ; ) is the Prefectures in France, prefecture and largest city of the Grand Est Regions of France, region of Geography of France, eastern France, in the historic region of Alsace. It is the prefecture of the Bas-Rhin Departmen ...
as a place of particular interest. Physicists
Rudolf Fleischmann and
Carl Friedrich von Weizsäcker were known to be working at the
University of Strasbourg
The University of Strasbourg (, Unistra) is a public research university located in Strasbourg, France, with over 52,000 students and 3,300 researchers. Founded in the 16th century by Johannes Sturm, it was a center of intellectual life during ...
, as was , an expert on viruses whose work was of great concern to the Alsos Mission's
Biological Warfare
Biological warfare, also known as germ warfare, is the use of biological toxins or Pathogen, infectious agents such as bacteria, viruses, insects, and Fungus, fungi with the intent to kill, harm or incapacitate humans, animals or plants as an ...
section. The Naval section was interested in the
torpedo
A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, such ...
research being carried out there, and jet engine development was being undertaken at Strasbourg's
Junkers
Junkers Flugzeug- und Motorenwerke AG (JFM, earlier JCO or JKO in World War I, English language, English: Junkers Aircraft and Motor Works) more commonly Junkers , was a major German aircraft manufacturer, aircraft and aircraft engine manufactu ...
plant.
On 22 November, the
U.S. Sixth Army Group notified the Alsos Mission that the capture of Strasbourg was imminent, and it should join T-Force in
Saarburg, where it was preparing to enter the city. The Alsos Mission joined T-Force in Strasbourg on 25 November. The German nuclear laboratory was discovered on the grounds of the Strasbourg Hospital, where the physicists attempted to pass themselves off as medics. Fleischmann was taken into custody, but Weizsäcker and Haagen had fled the city.
Documents discovered in Weizsäcker's office, Fleischmann's laboratory and the Strasbourg Hospital pointed to nuclear activities taking place at
Stadtilm,
Haigerloch
Haigerloch () is a town in the north-western part of the Swabian Alb in Germany.
Geography Geographical location
Haigerloch lies at between 430 and 550 metres elevation in the valley of the Eyach (Neckar), Eyach river, which forms two loops in a ...
,
Hechingen
Hechingen (; Swabian: ''Hächenga'') is a town in central Baden-Württemberg, Germany. It is situated about south of the state capital of Stuttgart and north of Lake Constance and the Swiss border.
Geography
The town lies at the foot of th ...
, and Tailfingen (today part of
Albstadt). After establishing its headquarters in Haagen's office Alsos staff uncovered documents concerning secret medical experiments at
Natzweiler concentration camp. These indicated the Germans had been unable to develop a practical process for
uranium enrichment
Enriched uranium is a type of uranium in which the percent composition of uranium-235 (written 235U) has been increased through the process of isotope separation. Naturally occurring uranium is composed of three major isotopes: uranium-238 (23 ...
. For the first time the Alsos Mission was able to categorically report that a German nuclear weapon was not a threat, as it had never gotten to a production phase. As Goudsmit put it later: "The conclusions were unmistakable. The evidence at hand proved definitely that Germany had no atom bomb and was not likely to have one in any reasonable time."
Germany
When the German
Operation Nordwind
Operation Northwind () was the last major German offensive of World War II on the Western Front. Northwind was launched to support the German Ardennes offensive campaign in the Battle of the Bulge, which by late December 1944 had decisively ...
offensive threatened Strasbourg, Pash ordered all captured documents to be removed. Papers indicating the nature of the Alsos Mission were removed or destroyed. Although Strasbourg was not abandoned by the Allies, and ultimately did not fall, the Alsos Mission departed the city on 8 January 1945. Pash even ordered an evacuation plan to be prepared for the Alsos Mission's main headquarters in Paris. The embarrassing series of intelligence failures that had led up to the
Battle of the Bulge
The Battle of the Bulge, also known as the Ardennes Offensive or Unternehmen Die Wacht am Rhein, Wacht am Rhein, was the last major German Offensive (military), offensive Military campaign, campaign on the Western Front (World War II), Western ...
cast doubts on the Alsos Mission's own findings. A four-man team under Eckman was sent to investigate a suspiciously devastating
V-2 explosion near Antwerp, and Fred Wardenburg had to confirm that it was not a small nuclear explosion.
Rumors that Germany had an atomic bomb persisted as late as March 1945, but all signs pointed to the lack of a production program. On March 16, Groves wrote to Bissell that "the most complete and factual information we have obtained bearing on the nature of the German effort in our field"— the results of the Strasbourg mission — "tends to confirm our conclusion that the Germans are now behind us."

A new forward headquarters, Alsos Forward North (AFwdN), was opened at
Aachen
Aachen is the List of cities in North Rhine-Westphalia by population, 13th-largest city in North Rhine-Westphalia and the List of cities in Germany by population, 27th-largest city of Germany, with around 261,000 inhabitants.
Aachen is locat ...
, and on 8 February the Alsos Mission reopened its forward headquarters in Strasbourg as Alsos Forward South (AFwdS). In March, the
U.S. Twelfth Army Group launched
Operation Lumberjack
Operation Lumberjack was a military operation with the goal of capturing the west bank of the Rhine River and seizing key German cities, near the end of World War II in Europe. The First United States Army launched the operation in March 1945 ...
, an offensive to clear the Germans west of the
Rhine
The Rhine ( ) is one of the List of rivers of Europe, major rivers in Europe. The river begins in the Swiss canton of Graubünden in the southeastern Swiss Alps. It forms part of the Swiss-Liechtenstein border, then part of the Austria–Swit ...
. Pash, who was promoted to
colonel
Colonel ( ; abbreviated as Col., Col, or COL) is a senior military Officer (armed forces), officer rank used in many countries. It is also used in some police forces and paramilitary organizations.
In the 17th, 18th, and 19th centuries, a colon ...
on 6 March, led an Alsos Mission detachment into
Cologne
Cologne ( ; ; ) is the largest city of the States of Germany, German state of North Rhine-Westphalia and the List of cities in Germany by population, fourth-most populous city of Germany with nearly 1.1 million inhabitants in the city pr ...
on 7 March, but little additional information was found.
The interrogation of German prisoners indicated that uranium and thorium were being processed in Germany, mostly at the ''
Auergesellschaft'' plant at
Oranienburg
Oranienburg () is a town in Brandenburg, Germany. It is the capital of the district of Oberhavel.
Geography
Oranienburg is on the banks of the River Havel, 35 km north of the centre of Berlin.
Division of the town
Oranienburg consists of ni ...
, so Groves arranged for the plant to be bombed on 15 March 1945. Some 612
B-17 Flying Fortress
The Boeing B-17 Flying Fortress is an American four-engined heavy bomber aircraft developed in the 1930s for the United States Army Air Corps (USAAC). A fast and high-flying bomber, the B-17 dropped more bombs than any other aircraft during ...
es of the
U.S. Eighth Air Force dropped 1,500 tons of high explosive and 178 tons of
incendiary bombs on the plant.
On 30 March, the Alsos Mission reached
Heidelberg
Heidelberg (; ; ) is the List of cities in Baden-Württemberg by population, fifth-largest city in the States of Germany, German state of Baden-Württemberg, and with a population of about 163,000, of which roughly a quarter consists of studen ...
, where important scientists were captured including
Walther Bothe
Walther Wilhelm Georg Bothe (; 8 January 1891 – 8 February 1957) was a German physicist who shared the 1954 Nobel Prize in Physics with Max Born "for the coincidence method and his discoveries made therewith".
He served in the military durin ...
,
Richard Kuhn
Richard Johann Kuhn (; 3 December 1900 – 31 July 1967) was an Austrian-German biochemist who was awarded the Nobel Prize in Chemistry in 1938 "for his work on carotenoids and vitamins".
Biography
Early life
Kuhn was born in Vienna, Austria ...
,
Philipp Lenard
Philipp Eduard Anton von Lenard (; ; 7 June 1862 – 20 May 1947) was a Hungarian-German physicist who received the Nobel Prize in Physics in 1905 "for his work on cathode rays" and the discovery of many of their properties. One of his most im ...
, and
Wolfgang Gertner. Their interrogation revealed that
Otto Hahn
Otto Hahn (; 8 March 1879 – 28 July 1968) was a German chemist who was a pioneer in the field of radiochemistry. He is referred to as the father of nuclear chemistry and discoverer of nuclear fission, the science behind nuclear reactors and ...
was at his laboratory in Tailfingen, while
Werner Heisenberg
Werner Karl Heisenberg (; ; 5 December 1901 – 1 February 1976) was a German theoretical physicist, one of the main pioneers of the theory of quantum mechanics and a principal scientist in the German nuclear program during World War II.
He pub ...
and
Max von Laue
Max Theodor Felix von Laue (; 9 October 1879 – 24 April 1960) was a German physicist who received the Nobel Prize in Physics in 1914 "for his discovery of the X-ray diffraction, diffraction of X-rays by crystals".
In addition to his scientifi ...
were at Heisenberg's laboratory in Hechingen, and the experimental natural uranium reactor that Heisenberg's team had built in Berlin had been moved to Haigerloch. Henceforth, the main focus of the Alsos Mission was on these nuclear facilities in the
Württemberg
Württemberg ( ; ) is a historical German territory roughly corresponding to the cultural and linguistic region of Swabia. The main town of the region is Stuttgart.
Together with Baden and Province of Hohenzollern, Hohenzollern, two other histo ...
area.
In April 1945 a four-man team under Hugh Montgomery uncovered the
Buchenwald concentration camp
Buchenwald (; 'beech forest') was a German Nazi concentration camp established on Ettersberg hill near Weimar, Nazi Germany, Germany, in July 1937. It was one of the first and the largest of the concentration camps within the Altreich (pre-1938 ...
and broke secrecy protocol to request medical help. The team was searching for a German nuclear physicist near Weimar, eastern Germany.
As the Allied armies advanced into Germany in April 1945, Alsos Mission teams searched Stadtilm, where they found documentation concerning the German nuclear program, components of a nuclear reactor, and eight tons of uranium oxide. Scientists captured at
Göttingen
Göttingen (, ; ; ) is a college town, university city in Lower Saxony, central Germany, the Capital (political), capital of Göttingen (district), the eponymous district. The River Leine runs through it. According to the 2022 German census, t ...
and
Katlenburg-Lindau included Werner Osenberg, the chief of the planning board of the ''Reichsforschungsrat'', and
Fritz Houtermans, who provided information about the
Soviet atomic bomb project
The Soviet atomic bomb project was authorized by Joseph Stalin in the Soviet Union to develop nuclear weapons during and after World War II.
Russian physicist Georgy Flyorov suspected that the Allied powers were secretly developing a " superwea ...
. At
Celle, the Alsos Mission uncovered an experimental
centrifuge
A centrifuge is a device that uses centrifugal force to subject a specimen to a specified constant force - for example, to separate various components of a fluid. This is achieved by spinning the fluid at high speed within a container, thereby ...
for separating uranium isotopes, the result of work undertaken at the
University of Hamburg
The University of Hamburg (, also referred to as UHH) is a public university, public research university in Hamburg, Germany. It was founded on 28 March 1919 by combining the previous General Lecture System ('':de:Allgemeines Vorlesungswesen, ...
by a team under
Paul Harteck.
The problem with the targets in the Württemberg area was that they not only lay in the path of the French
First Army's advance, but were also in the
occupation zone allocated to France. Groves attempted to get the occupation boundaries changed, but the
State Department
The United States Department of State (DOS), or simply the State Department, is an executive department of the U.S. federal government responsible for the country's foreign policy and relations. Equivalent to the ministry of foreign affairs o ...
wanted to know why first, and Groves refused to provide this information. Groves, Marshall, and Stimson then decided that the area would have to be secured by American troops that would carry off what they could and destroy everything else. Pash was sent to ask General
Jacob Devers, the commander of the
U.S. Sixth Army Group, if the zones of the French First Army and the
U.S. Seventh Army could be swapped around. He was informed that the matter would have to be taken up with Eisenhower.
Groves dispatched Lieutenant Colonel
John Lansdale Jr. to Europe, where he participated in a meeting with Lieutenant General Bedell Smith and Major General
Harold Bull of
SHAEF
Supreme Headquarters Allied Expeditionary Force (SHAEF; ) was the headquarters of the Commander of Allies of World War II, Allied forces in northwest Europe, from late 1943 until the end of World War II. US General Dwight D. Eisenhower was the ...
; Major General
Elbridge Chapman, the commander of the
U.S. 13th Airborne Division; Pash, Furman, and Goudsmit of Alsos; and Brigadier General
Reuben E. Jenkins from the Sixth Army Group. The plan, codenamed
Operation Effective, called for the 13th Airborne Division to occupy the area to prevent its capture by the French, and seize an airfield that could be used to fly in an Alsos Mission team, and later to fly it out, along with captured German scientists. Operation Effective was scheduled for 22 April. Meanwhile, Devers took steps to delay the French advance.

The Alsos Mission had learned that the uranium ores that had been taken from Belgium in 1944 had been shipped to the ''
Wirtschaftliche Forschungsgesellschaft'' (WiFO) plant in
Staßfurt. The
83rd Infantry Division captured this on 15 April. As it was in the
occupation zone allocated to the Soviet Union at the
Yalta Conference
The Yalta Conference (), held 4–11 February 1945, was the World War II meeting of the heads of government of the United States, the United Kingdom, and the Soviet Union to discuss the postwar reorganization of Germany and Europe. The three sta ...
, the Alsos Mission, led by Pash and accompanied by Lansdale, Perrin and
Air Commodore
Air commodore (Air Cdre or Air Cmde) is an air officer rank used by some air forces, with origins from the Royal Air Force. The rank is also used by the air forces of many countries which have historical British influence and it is sometimes ...
Sir
Charles Hambro, arrived on 17 April to remove anything of interest. Over the following ten days, 260 truckloads of uranium ore,
sodium uranate and
ferrouranium weighing about 1,000 tons, were taken away by an African-American truck company. The uranium was taken to
Hildesheim
Hildesheim (; or ; ) is a city in Lower Saxony, in north-central Germany with 101,693 inhabitants. It is in the district of Hildesheim (district), Hildesheim, about southeast of Hanover on the banks of the Innerste River, a small tributary of t ...
and most of it was flown to the United Kingdom by the Royal Air Force; the rest had to be moved to Antwerp by train and loaded onto a ship to England.
On 20 April, the French First Army captured an intact bridge over the
Neckar
The Neckar () is a river in Germany, mainly flowing through the southwestern States of Germany, state of Baden-Württemberg, with a short section through Hesse. The Neckar is a major right tributary of the Rhine. Rising in the Schwarzwald-Baar ...
River at
Horb and established a bridgehead. It was decided to send in a force on the ground instead of Operation Effective, which was cancelled on 19 April. This time, instead of following or accompanying the front-line troops, the Alsos Mission would operate behind enemy lines. The Alsos Mission had taken delivery of two armored cars, four jeeps with machine gun mounts, and two
.50 caliber machine guns. The other two jeeps would carry captured German machine guns. They would be accompanied by three unarmed jeeps. For the operation, codenamed
Operation Big, Pash would command a special force called Task Force A, built around his Alsos Mission team and the U.S.
1269th Engineer Combat Battalion commanded by Lieutenant Colonel Wilbur White, less its Company B. Sir Charles Hambro decided to accompany the Alsos Mission with a British group that included Michael Perrin, David Gattiker, Eric Welsh, and Rupert Cecil. Lansdale accompanied Task Force A as Groves' representative, and Brigadier General
Eugene L. Harrison, the G-2 from the Sixth Army Group, as Devers' representative.

The Alsos Mission set out on 20 April and rendezvoused with the 1269th Engineer Combat Battalion at
Freudenstadt. The intact bridge over the Neckar River at Horb was crossed and Haigerloch was occupied without opposition on 22 April. The main body of Task Force A arrived on 23 April. In a laboratory in a cellar they found a German experimental
nuclear reactor
A nuclear reactor is a device used to initiate and control a Nuclear fission, fission nuclear chain reaction. They are used for Nuclear power, commercial electricity, nuclear marine propulsion, marine propulsion, Weapons-grade plutonium, weapons ...
shaped like a cylinder and made of
graphite
Graphite () is a Crystallinity, crystalline allotrope (form) of the element carbon. It consists of many stacked Layered materials, layers of graphene, typically in excess of hundreds of layers. Graphite occurs naturally and is the most stable ...
blocks, but the uranium and heavy water were missing. The scientists immediately began dismantling it. Pash left Hambro in charge, while he led troops of Task Force A to
Bisingen, and then on to Hechingen, where 25 scientists were captured, including Weizsäcker, Laue,
Karl Wirtz,
Horst Korsching and Erich Bagge. At Tailfingen they took Otto Hahn and nine members of his staff into custody. At Haigerloch, a sealed drum of documents was retrieved from a cesspool, and three drums of heavy water and 1.5 tons of uranium ingots were found buried in a field. The uranium and heavy water were loaded onto trucks. The apertures in the cellar were blown up with minor explosions to prevent their capture by the French.
Werner Heisenberg, "Germany's
Oppenheimer" according to
Gregg Herken, remained at large, having left Hechingen on 19 April. On 1 May, Pash set out in pursuit of Heisenberg with ten men in the two armored cars and two jeeps. They teamed up with the 36th Reconnaissance Troop of the
U.S. 36th Infantry Division and entered
Urfeld on 2 May, where Pash found Heisenberg at his home. The Americans became involved in firefights with German troops attempting to enter the town, and the 36th Reconnaissance Troop had to head off on another mission, leaving Pash with just seven men. Fortunately, the German force, which numbered about 700, offered to surrender. Pash returned on 3 May with the 3rd Battalion,
142nd Infantry, which took them prisoner, while Pash and his Alsos Mission team took Heisenberg into custody.
By
VE day
Victory in Europe Day is the day celebrating the formal acceptance by the Allies of World War II of Germany's unconditional surrender of its armed forces on Tuesday, 8 May 1945; it marked the official surrender of all German military operations ...
, the Alsos Mission had a strength of 114 men and women. It was officially disbanded on 15 October 1945.
Operation Epsilon
German scientists that had been captured by the Alsos Mission were held in several camps, separate from other
prisoners of war
A prisoner of war (POW) is a person held captive by a belligerent power during or immediately after an armed conflict. The earliest recorded usage of the phrase "prisoner of war" dates back to 1610.
Belligerents hold prisoners of war for a ...
. After VE Day, SHAEF decided to concentrate them in an internment camp at
Kransberg Castle, codenamed "Dustbin", as part of
Operation Epsilon
Operation Epsilon was the codename of a program in which Allies of World War II, Allied forces near the end of World War II detained ten Germany, German scientists who were thought to have worked on German nuclear energy project, Nazi Germany's n ...
. At Welsh's instigation, ten of the nuclear physicists, Bagge, Diebner, Gerlach, Hahn, Harteck, Heisenberg, Korsching, von Laue, von Weizsäcker and Wirtz, were brought to England. They were accommodated between 3 July 1945 and 3 January 1946 at
Farm Hall, a house in
Godmanchester
Godmanchester ( ) is a town and Civil parishes in England, civil parish in the Huntingdonshire district of Cambridgeshire, England. It is separated from Huntingdon, to the north, by the valley of the River Great Ouse. Being on the Roman roads ...
, near
Cambridge
Cambridge ( ) is a List of cities in the United Kingdom, city and non-metropolitan district in the county of Cambridgeshire, England. It is the county town of Cambridgeshire and is located on the River Cam, north of London. As of the 2021 Unit ...
. The premises were thoroughly
bugged to determine how close the German nuclear project had been to constructing an atomic bomb by listening in to their conversations and transcripts of their conversations were sent to Groves. The most interesting conversations occurred after they received the news of the
atomic bombing of Hiroshima and Nagasaki, when they struggled to comprehend how the Allies had done what they could not.
Japan
Plans for the
invasion of Japan incorporated an Alsos Mission. Japanese
fire balloon attacks on the United States had aroused fears that the technique might be used in combination with biological agents, which the Japanese
Unit 731
, short for Manchu Detachment 731 and also known as the Kamo Detachment and the Ishii Unit, was a covert biological and chemical warfare research and development unit of the Imperial Japanese Army that engaged in lethal human experimentat ...
was known to be experimenting with. In March 1945, the physicist and seismologist
L. Don Leet was appointed as head of the scientific section of the Alsos Mission to Japan. Leet had previously worked with the Manhattan Project on the
Trinity nuclear test.
Plans were drawn up to prepare and equip a T-Force along the lines of the one in Europe, but made up of personnel already in the Pacific. The mission differed from its European counterpart in that it was solely American and consisted of only one intelligence agency. Responsibility for nuclear matters was subsequently handled by a separate Manhattan Project Intelligence Group organized by Groves.
Leet's group reached
Manila
Manila, officially the City of Manila, is the Capital of the Philippines, capital and second-most populous city of the Philippines after Quezon City, with a population of 1,846,513 people in 2020. Located on the eastern shore of Manila Bay on ...
in July 1945, where they met with the intelligence staff of
General of the Army
Army general or General of the army is the highest ranked general officer in many countries that use the French Revolutionary System. Army general is normally the highest rank used in peacetime.
In countries that adopt the general officer fou ...
Douglas MacArthur
Douglas MacArthur (26 January 18805 April 1964) was an American general who served as a top commander during World War II and the Korean War, achieving the rank of General of the Army (United States), General of the Army. He served with dis ...
's
Army Forces, Pacific. Following the
surrender of Japan
The surrender of the Empire of Japan in World War II was Hirohito surrender broadcast, announced by Emperor Hirohito on 15 August and formally Japanese Instrument of Surrender, signed on 2 September 1945, End of World War II in Asia, ending ...
the mission traveled to Japan and visited various research establishments including
Tokyo Imperial University
The University of Tokyo (, abbreviated as in Japanese and UTokyo in English) is a public university, public research university in Bunkyō, Tokyo, Japan. Founded in 1877 as the nation's first modern university by the merger of several Edo peri ...
,
Waseda University
Waseda University (Japanese: ), abbreviated as or , is a private university, private research university in Shinjuku, Tokyo. Founded in 1882 as the Tōkyō Professional School by Ōkuma Shigenobu, the fifth Prime Minister of Japan, prime ministe ...
,
Tokyo Institute of Technology
The Tokyo Institute of Technology () was a public university in Meguro, Tokyo, Japan. It merged with Tokyo Medical and Dental University to form the Institute of Science Tokyo on 1 October 2024.
The Tokyo Institute of Technology was a De ...
, the
Institute of Physical and Chemical Research, the
Institute for Materials Research, Tokyo Shibaura Denki (
Toshiba
is a Japanese multinational electronics company headquartered in Minato, Tokyo. Its diversified products and services include power, industrial and social infrastructure systems, elevators and escalators, electronic components, semiconductors ...
), the
Japan Society for the Promotion of Science
The is an Independent Administrative Institution in Japan, established for the purpose of contributing to the advancement of science in all fields of the natural and social sciences and the humanities.JSPSweb page
History
The Japan Society f ...
, the National Research Council, and the Board of Technology. The mission, which included
Karl Compton, interviewed over 300 Japanese scientists and produced reports on Japanese research into
radar
Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...
, rockets, and other developments, including chemical and biological warfare. The Manhattan Project Intelligence Group, under the command of
Philip Morrison, arrived in Japan in September 1945 and examined Japan's wartime nuclear weapons program. The group concluded that lack of uranium ore and low priority had doomed the Japanese effort. They reported that, contrary to American belief, Japan's nuclear physicists were competent.
Legacy
After seeing the
German project at Haigerloch, Goudsmit wrote that:
In the end, the Alsos Mission contributed little to the Allied defeat of Nazi Germany, because the German nuclear and biological weapons programs that it had been formed to investigate turned out to be smaller and less threatening than had been feared. In the field of nuclear weapons development at least, the underfunded and disorganized German program lagged far behind the Allies' own efforts. In its appropriation of the accomplishments of European science, the Alsos Mission played a small part in the wartime and subsequent scientific and technological developments that characterized and transformed the postwar world.
See also
*
Norwegian heavy water sabotage
*
Operation Paperclip
The Operation Paperclip was a secret United States intelligence program in which more than 1,600 German scientists, engineers, and technicians were taken from former Nazi Germany to the US for government employment after the end of World War I ...
*
Russian Alsos
Notes
References
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{{Portal bar, Germany, Nuclear technology
Battles and operations of World War II involving Norway
Espionage projects
World War II intelligence operations
Technical intelligence during World War II
History of the Manhattan Project
Nuclear program of Nazi Germany
Office of Naval Intelligence
World War II operations and battles of Europe