Editing Manhattan Project (section)

== Foreign intelligence ==
{{Main|Alsos Mission}}
In addition to developing the atomic bomb, the Manhattan Project was charged with gathering intelligence on the [[German nuclear energy project]]. It was believed that the [[Japanese nuclear weapons program]] was not far advanced because Japan had little access to uranium ore, but it was initially feared that Germany was very close to developing its own weapons. At the instigation of the Manhattan Project, a [[Norwegian heavy water sabotage|bombing and sabotage campaign]] was carried out against heavy water plants in German-occupied Norway.<ref>{{harvnb|Groves|1962|pp=191–192}}.</ref> A small mission was created, jointly staffed by the [[Office of Naval Intelligence]], OSRD, the Manhattan Project, and Army Intelligence (G-2), to investigate enemy scientific developments. It was not restricted to those involving nuclear weapons.<ref>{{harvnb|Groves|1962|pp=187–190}}.</ref> The Chief of Army Intelligence, Major General [[George V. Strong]], appointed [[Boris Pash]] to command the unit,<ref>{{harvnb|Jones|1985|p=281}}.</ref> which was codenamed "Alsos" (Greek for "grove").<ref>{{harvnb|Groves|1962|p=191}}.</ref> [[Samuel Goudsmit]] was the scientific director of  the Alsos mission.<ref>{{harvnb|Jones|1985|p=285}}.</ref>

[[File:German Experimental Pile - Haigerloch - April 1945.jpg|thumb|Allied soldiers dismantle the German experimental [[Haigerloch research reactor|nuclear reactor at Haigerloch]].|alt=Soldiers and workmen, some wearing steel helmet, clamber over what looks like a giant manhole.]]
The Alsos Mission to Italy questioned physics laboratory staff at the [[Sapienza University of Rome|University of Rome]] following the capture of the city in June 1944.<ref>{{harvnb|Jones|1985|p=282}}.</ref> Meanwhile, Pash formed a combined British and American Alsos mission in London under the command of Captain Horace K. Calvert to participate in [[Operation Overlord]].<ref>{{harvnb|Groves|1962|pp=194–196}}.</ref> Groves considered the risk that the Germans might attempt to disrupt the [[Normandy landings]] with radioactive poisons was sufficient to warn General [[Dwight D. Eisenhower]] and send an officer to brief his chief of staff, Lieutenant General [[Walter Bedell Smith]].<ref>{{harvnb|Groves|1962|pp=200–206}}.</ref> Under the codename [[Operation Peppermint]], special equipment was prepared and [[Chemical Warfare Service]] teams were trained in its use.<ref>{{harvnb|Jones|1985|pp=283–285}}.</ref>

Following in the wake of the advancing Allied armies, the Alsos team interrogated scientists and searched facilities in liberated areas of France and Germany to learn about the German work. Goudsmit concluded in November 1944 that the German nuclear program had never made it beyond the laboratory stage. As he put it later: "The evidence at hand proved definitely that Germany had no atom bomb and was not likely to have one in any reasonable time."<ref>{{harvnb|Goudsmit|1947|pp=70&ndash;71}}.</ref>

Interrogation of German prisoners indicated that uranium and thorium were being processed in [[Oranienburg]], so Groves [[Auergesellschaft#Russian Alsos|arranged for it to be bombed]] on 15 March 1945 to deny its capture by the Soviet Union.<ref>{{harvnb|Jones|1985|pp=286–288}}.</ref> An Alsos team went to [[Stassfurt]] in the [[Soviet Occupation Zone]] and retrieved 11 tons of ore from [[WIFO (Nazi company)|WIFO]].<ref>{{harvnb|Groves|1962|p=237}}.</ref> In April 1945, Pash, in command of a composite force known as T-Force, conducted [[Operation Harborage]], a sweep behind enemy lines of [[Hechingen]], [[Bisingen]], and [[Haigerloch]]—the heart of the German nuclear effort. T-Force captured nuclear laboratories, documents, equipment and supplies, including heavy water and 1.5 tons of metallic uranium.<ref>{{harvnb|Jones|1985|pp=289–290}}.</ref><ref>{{harvnb|Goudsmit|1947|pp=174–176}}.</ref>

Alsos teams rounded up German scientists including [[Kurt Diebner]], [[Otto Hahn]], [[Walther Gerlach]], [[Werner Heisenberg]], and [[Carl Friedrich von Weizsäcker]]. They were taken to England and interned at [[Farm Hall]], where they were surreptitiously surveilled.<ref>{{harvnb|Groves|1962|pp=333–340}}.</ref>