Fathers of a Thousand Suns

(Väter der tausend Sonnen)

GDR, 1989, 87 min, color/b&w
In German; English subtitles
Music (Score)
Production Company


The documentary tells the story of the German scientist Klaus Fuchs (1911-1988), who, in 1941, joined the British atomic project Tube Alloys, and three years later, J. Robert Oppenheimer’s Manhattan Project, the highly secret Los Alamos Laboratory located in the New Mexico desert. Fuchs became a spy for the Soviet Union while conducting nuclear research in the United States and Britain. The rediscovered documentary, Fathers of a Thousand Suns, portrays Klaus Fuchs and other physicists who faced moral dilemma in relation to atomic warfare during and especially after WWII.


Director Joachim Hellwig used footage and photos from international archives and private collections in Berlin, Cambridge, Dresden, Hamburg, London, Los Alamos, Moscow, Munich, Oxford, Santa Fé, Washington D.C. and Zurich.and interviewed over twenty people, including scientists involved in the American Manhattan and British Tube Alloys atomic projects, Klaus Fuchs’s intelligence handlers and family members. Hellwig also included clips from a 1983 filmed interview with Klaus Fuchs that was conducted by Markus Wolf, founding member and chief of the East German Foreign Intelligence Service within the Ministry for State Security.


The following people are interviewed in the documentary:

  • Ardenne, Manfred von (1907-97, [East] German researcher and applied physicist, inventor)
  • Baudissin, Wolf von (1907-93, German lieutenant general, military theorist, peace researcher)
  • Bernhard, Fritz (1913-93, [East] German physicist)
  • Feklisov, Aleksandr S. (1914-2007, Soviet spy, KGB, NKVD case officer who handled Julius Rosenberg and Klaus Fuchs)
  • Flach, Günter (1932-2020, [East] German physicist)
  • Flerov Georgii, Nikolaevich (1913-90, Soviet nuclear physicist and chemist, worked on the Soviet atomic project)
  • Fuchs-Holzer, Christel (1913-2008, Klaus Fuchs’ sister, peace worker, lived in the USA)
  • Fuchs-Keilson, Margarete “Grete” (1905-99, Klaus Fuchs’s wife, [East] German politician)
  • Fuchs-Kittowski, Klaus (1934- , Klaus Fuchs’s nephew, [East] German computer scientist, philosopher)
  • Fuchs, Klaus (1911-88, [East] German nuclear physicist)
  • Haxel, Otto (1909-98, German nuclear physicist)
  • Jungk, Robert (1913-94, Austrian writer, journalist, historian and peace campaigner) 
  • Kuczynski, Jürgen (1904-97, [East] German economist, journalist, communist)
  • Meyer, Wolfgang (co-writer, co-director of Klaus Fuchs – Atomspy, 1989, Germany/Switzerland)
  • Mott Nevill, Francis (1905-96, British physicist, winner of the Nobel Prize for Physics)
  • Peierls, Rudolf (1907-95, German-born British physicist, member of the British Tube Alloys atomic project)
  • Rotblat, Joseph (1908-2005, Polish British physicist, member of the British Tube Alloys and Manhattan Project)
  • Weisskopf, Victor (1908-2002, Austrian-American theoretical physicist, member of the Manhattan Project)
  • Weizsäcker, Carl Friedrich von (1912-2007, German physicist and philosopher)
  • Werner, Ruth (1907-2000, [East] German writer, Jürgen Kuczynski’s sister, Klaus Fuchs’s handler for Soviet intelligence)
  • Wirtz, Karl (1910-94, German nuclear physicist)



This East German documentary provides important context to the ongoing discussions of the War in Ukraine and the 2023 release of the Hollywood film Oppenheimer (dir. Christopher Nolan, USA). For the first time, this unique German-language film is now accessible to an English-speaking audience with subtitles that were created by Barton Byg, UMass professor emeritus, and the DEFA Film Library.


Dubini, Donatello and Fosco Dubini, Wolfgang Meyer. Klaus Fuchs - Atomspion. Germany/Switzerland, 1989, documentary.

Goodermote, Cedric. Klaus Fuchs & Atom Bomb: The Spy Who Handed America's Secrets to the Soviets. Independently published, 2021.

Goodman, Michael S. “The Grandfather of the Hydrogen Bomb?: Anglo-American Intelligence and Klaus Fuchs.” Historical Studies in the Physical and Biological Science, Vol. 34, No. 1 (2003), 1-22.

Greenspan, Nancy Thorndike. Atomic Spy. The Dark Lives of Klaus Fuchs. New York: Penguin Books, 2021.

Moss, Norman. Klaus Fuchs: The Man Who Stole the Atom Bomb. Independently published, 2018.

Pagel, Leroy. Klaus Fuchs: The Physicist Who Gave Atom Secrets to Soviet. Independently published, 2021.

Rossiter, Mike. The Spy Who Changed the World: Klaus Fuchs, Physicist and Soviet Double Agent. New York: Skyhorse, 2017.

Williams, Robert Chadwell. Klaus Fuchs - Atom Spy. Cambridge: Harvard U Press, 1987.

Press comments

"The Russian-Ukrainian War and the 2023 release of the Hollywood movie Oppenheimer (USA, dir. Christopher Nolan) make access to this East German documentary very timely."   —Christoph Schmauch, World Fellowship Center director emeritus


“A factual documentary about the famous "atomic spy" Klaus Fuchs (1911-1988). After the physicist had emigrated to the USA in 1933, he worked on the American-English nuclear weapons program and passed on his knowledge to the Soviet Union in the 1940s. Fuchs’s cover was blown in 1949 and he was imprisoned in England. He was considered 'persona non grata' in the Soviet Union. After his release from prison, he moved to East Germany, but his story was hushed up for decades. Only after his death, the film director was able to realize the film project he had been planning for two decades.”   —filmdienst.de




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