Helmut Gröttrup

Helmut Gröttrup as GAO managing director, around 1977

Helmut Gröttrup (born February 12, 1916 in Cologne , † July 4, 1981 in Munich ) was a German engineer . He was responsible for the on-board systems and control in the German Aggregat 4 (V2) project and for the Soviet missile development , was then involved in the development of electronic systems for logistics control, operational data acquisition and identification systems and invented the basics of the chip card .

Youth and education

Helmut Gröttrup's father Johann Gröttrup (1881–1940) was a mechanical engineer. He worked full time at the collar of the technical staff and officials (Butab), a social-democratic oriented trade union in Berlin . His mother Thérèse Gröttrup (1894–1981), b. Elsen was active in the peace movement. Johann Gröttrup became unemployed in 1933. Helmut Gröttrup graduated from high school in 1935 and began studying physics at the Technical University of Berlin in 1936 . In the same year he was classified as "suitable" by the military district command and postponed until 1939. In 1939 he finished his studies in physics with a very good. He wrote his diploma thesis on counter tube physics with Prof. Hans Geiger , which he also completed with very good. After completing his studies, he worked in the "Research Laboratory for Electron Physics" in Berlin-Lichterfelde with Manfred von Ardenne , which he had to leave at the end of September 1939 in order to follow a presentation order to Peenemünde .

A4 (V2) project

From December 1939, Helmut Gröttrup was development engineer at the Peenemünde Army Research Institute for the areas of measurement technology , radio data transmission, remote control and autonomous controls. As assistant to the head of development, Wernher von Braun , Gröttrup was involved in the construction of the large aggregate 4 rocket (known as V2). Gröttrup developed the steering and control systems of the A4 under Ernst Steinhoff in the on -board, control and measuring devices (BSM) department and, with his extensive physical knowledge, was able to contribute a great deal to error analysis in the event of a crash. The central control and regulation functions were carried out by the so-called "mixer", an electronic analog computer based on tubes that Helmut Hölzer had developed.

On the night of March 21-22, 1944, Gröttrup was arrested by the Gestapo together with Wernher and Magnus von Braun as well as Klaus Riedel and taken to the prison in Stettin , a few days later his wife Irmgard Gröttrup as well. They were accused of defeatism and defeatism of working more for manned space travel than for missiles used for war purposes. Walter Dornberger , Major General of the Wehrmacht and military head of the German missile program, was able to obtain their release within ten days with the support of HVP Defense Commissioner Major Hans Georg Klamroth , because they were indispensable for the development of the A4. Gröttrup's trial was suspended until the end of the war, but he remained in the custody of the SS security service .

He then worked under conditions similar to detention in Pudagla and Schwedt / Oder on the further development of the A4 until the Dornberger staff with 450 employees was relocated to the area around Bad Sachsa and Bleicherode on February 17, 1945 while fleeing from the Soviet army and thus in the proximity of the Mittelwerk GmbH near Nordhausen, which has existed since September 1943 . On April 6, 1945, the scientists were brought by train from Bleicherode to Oberammergau, under the supervision of the SS, in order to remove them from the US Army or to use them as bargaining chips. On this transport, Gröttrup, who was threatened by another arrest warrant and execution by the SS, left Freising and fled to his family in Stöckey near Bad Sachsa, who were already under US control. Since Thuringia was to be handed over to the Red Army on July 1, 1945, the US Army brought around 1000 employees of the German missile program, including the Gröttrup family, from the southern Harz around Bleicherode and Nordhausen to Witzenhausen in northern Hesse by June 22, 1945 . There, Gröttrup was interned together with Wernher von Braun, Walter Dornberger and other important experts, initially under strict guard.

Soviet missile program

Since Helmut Gröttrup did not want to separate from his family, he refused to work for the Americans in the USA as part of Operation Paperclip , as did many well-known A4-development scientists from Peenemünde and others. a. Wernher von Braun, Walter Dornberger and Ernst Steinhoff, who were initially interned. The Soviet Union made it possible for Gröttrup to continue his work in Germany and to stay with his family. He was the most important German missile specialist that the Soviet Union was able to secure for its missile program.

As of July 1, 1945, the American occupation forces handed Thuringia over to the Red Army , as agreed at the Yalta Conference , after they had brought all the technical documents stored in the Mittelwerk and 110 A4 with 341 freight wagons to the West and later to the USA would have. Prefabricated components and especially rocket engines, however, were in abundance in the Mittelwerk's production facilities, which the Americans had left behind , for extensive analyzes and the complete assembly of another 40 A4 or so. However, the design and production documents for the A4 had to be reconstructed practically from zero in the Soviet occupation zone . The Soviets therefore founded the Rabe Institute (rocket construction and development) in July 1945 and the Gröttrup office in Bleicherode in September 1945 , initially under the direction of Boris Tschertok , a Soviet missile specialist.

In February 1946 the Rabe Institute and the Gröttrup Office were merged to form the Nordhausen Institute (also known as Zentralwerke ) under the direction of Major General Lev Gajdukow and the Soviet space pioneer Sergei Koroljow as chief designer . The German management was given to Helmut Gröttrup as General Director. More than 4,000 employees worked to restore the A4's engineering documents, improve development and resume production of the A4 and its components. In July 1946 the American and British secret services tried to poach Gröttrup to the West, but their intentions were uncovered by the Soviet secret service NKVD . Gröttrup was interrogated and placed under observation by Ivan Serow , the head of the Soviet military administration in Germany (SMAD) and later head of the KGB .

Since the A4 rocket was an armaments item, its development and production in Germany was a clear violation of the Potsdam Agreement . On May 13, 1946, the Soviet Council of Ministers decided to transfer the German specialists to the USSR by the end of 1946 and initiated the corresponding secret preparations. On 22 October 1946 the scope of the were operation osoaviakhim about 160 selected scientists and engineers at the Institute Nordhausen worked, dragged forcibly along with their families by train to the Soviet Union, among them Helmut Gröttrup, the specialist in aerodynamics Werner Albring , the Engineer for control and measurement technology Heinrich Wilhelmi and the expert for gyro systems Kurt Magnus . Gröttrup and other specialists initially stayed in Podlipki near Moscow, while the other half was immediately taken to the island of Gorodomlja (today the Solnetschny settlement ) in Lake Seliger , approx. 380 km northwest of Moscow. The Gröttrup family, together with the last of the German group, were also brought to Gorodomlja in May 1948, which they were only allowed to leave with Soviet escort.

In the newly established Branch 1 of the Research and Development Institute for Space Rockets NII-88 (Russian научно-исследовательский институт) under the direction of Sergei Koroljow and Helmut Gröttrup as the head of the German production team, the German specialists continued their work to get the A4 up and running. By November 13, 1947, five A4 rockets had been launched entirely in Germany and six had only been assembled in the Soviet Union. After German specialists, including Helmut Gröttrup and Johannes Hoch, had solved a problem with the gyro control on site, a total of five starts were completely successful and two others were partially successful. The German collective constructed many improvements for the R-1 , which was built almost entirely from Soviet production and which was first launched in October 1948, also to replace very special materials and improve the accuracy of the control. Then it worked out the G-1 project with completion on December 28, 1948, the G-2 and G-4 project with completion on December 7, 1949. The Council of Ministers of the USSR decided with Decree No. 3456 on August 13, 1950 to forego the cooperation of the German specialists, withdrew them from the rocket projects and kept them busy for a long time in order to make their specialist knowledge about rockets obsolete.

The German collective had to stay on Gorodomlja before the first families were allowed to return home in June 1952. On November 22, 1953 returned Gröttrup with his family as the last German scientists to Germany and fled in December 1953 with the help of American and British intelligence services of East Berlin to Cologne and was the British Joint Intelligence Committee as part of Operation Dragon Return to State of Soviet missile development asked. Gröttrup warned clearly not to underestimate the Soviet skills and determination.

Helmut Gröttrup in 1958 in Bremen explaining the basic principle of the rocket

The A4 formed an essential basis for the Soviet missile program and was the template for the improved R-2 and the first ICBM R-7 . The mostly theoretical work of the German scientists, who proposed improved and simplified solutions for the G-1 and G-4 concepts due to a lack of material and new ideas from the experts, made a significant contribution to the success of Soviet space travel and its dominance until 1965. This began in October 1957 with the launch of the first Sputnik satellite into orbit and was continued in April 1961 with Yuri Gagarin as the first cosmonaut . The R-7 used as a launch vehicle was based on a bundling of a total of 20 A4-like engines with cone-shaped missile bodies, as the German scientists in Gorodomlja had already proposed in 1949 in the G-4 concept, which was positively approved by Soviet experts. For political reasons, however, the contributions of the German collective to Soviet missile development were for a long time classified as insignificant in public.

Helmut Gröttrup was with Irmgard Gröttrup (1920–1991), b. Rohe, married, whose book The Possessed and the Mighty about the six years in the Soviet Union was published in 1958 and provides detailed information about this time in diary-like memories. The small technical digression in the epilogue comes to the following conclusion:

“Like any other long-range rocket, the R14 is a step on the way to a space rocket that will first advance unmanned, and perhaps later manned, to other stars. The rocket engineers around the world dream of the day when the governments of their countries recognize the nonsense of the war and renounce the misuse of rockets as weapons. Then it will be possible to make the enormous funds previously spent on armaments available for research. In this, the missile is assigned an important role. "

- Helmut Gröttrup : The possessed and the mighty (1958), p. 241

Critique of manned space travel

In an interview on the occasion of the US moon landing in July 1969, Gröttrup criticized the high costs of manned space travel and confronted Wernher von Braun with the thesis that automatic space probes can achieve the same scientific data with an effort of only 10 or 20 percent of the costs that the money should better be spent on other purposes. Von Braun justified manned space travel with the argument that it would help mankind to immortality if they had to migrate from an uninhabitable earth to another planet .

Computer science

Back in Germany, he worked at Standard Elektrik AG and, after its merger with C. Lorenz, worked for its successor, Standard Elektrik Lorenz in Pforzheim (1954–1958). In 1957, Gröttrup and Karl Steinbuch became known for coining the term computer science . He played a key role in the world's first commercial data processing application based on a special computer architecture for monitoring inventory levels and controlling the order processing of Quelle shipping . He then worked as plant manager for the Josef Mayr electrical engineering factory in Pforzheim, which was taken over by Siemens & Halske in April 1960 and relocated to Munich in 1963 . There he worked on setting up a new area of ​​work for production planning with the help of integrated data processing. In April 1965, Gröttrup went into business for himself and founded the Datentechnische Gesellschaft (DATEGE), which, among other things, presented a matrix printer (then called a mosaic printer) at the Hanover Fair and developed electrically coded access systems.

Invention of the chip card

In 1966, Gröttrup registered an “identification switch” for identifying customers and releasing the tapping process in a petrol station or for tracking an object for a patent . He first tried to record the information electromechanically or in sequentially readable electronic memories. On February 6, 1967, Gröttrup registered DE1574074, a "counterfeit-proof identification switch" based on a monolithically integrated semiconductor, which is very compact and has no lines to the outside. According to this invention, the information “cannot be imitated by discrete components” due to the dimensions that have also been tested. The identification data are dynamically varied by integrated counters so that the underlying key cannot be copied by simply reading it out and therefore remains hidden in the chip. In a parallel application DE1574075, Gröttrup described the wireless transmission by inductive coupling, which later led to RFID technology. These two inventions contain the essential elements for the functional principle and the security of all subsequent applications of the chip card for payment transactions, telephone cards , SIM cards as well as identity systems and ID cards. With this, Helmut Gröttrup took the first decisive step for the invention of the chip card.

On September 13, 1968, more than 18 months later, Gröttrup submitted the patent application “identification switch” in Austria, in which the “counterfeit-proof identification switch” filed in 1967, enriched with further technical embodiments, is described and claimed again. In this application, Gröttrup's new business partner Jürgen Dethloff was named as co-inventor. This re-registration was possible because the two German applications not from 1967 as Offenlegungsschrift were released. On May 15, 1970, the Austrian Patent Office granted patent AT287366B. With reference to the Austrian priority of 1968, patent protection was also applied for in Germany and obtained on April 1, 1982 with patent grant DE1945777C3. The patent protection was largely reduced to the content of the previous patent application from 1967. The German Patent and Trademark Office (DPMA) names the chip card as a milestone in the history of technology among the inventions that have a decisive influence on everyday life. On this basis, the priority date (September 13, 1968) and the named inventor of the patents granted in Austria and Germany are used as a basis for the invention of the chip card, especially since on this basis patent protection in other important industrialized countries, u. a. France, UK and USA.

Banknote processing and machine readable features

From July 1970, Gröttrup headed the Gesellschaft für Automation und Organization mbH (GAO) founded by Siegfried Otto , the owner of the Giesecke & Devrient banknote printing company in Munich, and laid the basis for the later successful product area of ​​chip cards for payment and security systems in the cards division (since April 2018 G + D Mobile Security GmbH). In 1979, GAO produced the world's first standard-compliant chip cards (size 85.60 mm × 53.98 mm, thickness 0.76 mm) on a laboratory scale. In addition, as managing director, Gröttrup was responsible for setting up the product area for automated banknotes with machine-readable security features for the detection of counterfeit money and the development of systems for automated banknote processing. The semi-automatic ISS 300 model initially achieved a processing speed of 4 banknotes per second and was introduced at the Deutsche Bundesbank in 1977. The ISS 300 was sold in 67 countries, setting a global standard for banknote processing systems. It has been in operation at the Deutsches Museum since 2006 and, as an early example of automatic pattern recognition, demonstrates an important application of computer science.

The functional prototype of the ISS 3000 model, the first fully automatic machine with a very ambitious 40 banknotes per second, was tested at the Federal Reserve Bank of New York in 1977 , but was fundamentally revised until the start of series production in 1987, before the system was widely used by the Federal Reserve Bank as the BPS 3000 the United States was deployed. The banknote processing division (since April 2018 G + D Currency Technology GmbH, Currency Management Systems division) has developed on this basis since the mid-1990s into the world market leader for equipping central banks and quality testing in banknote printing plants.

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  Function control sample of the first ISS 300 banknote processing machine from GAO ​​(1974)

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  Sensor section of the ISS 300 FKM (1974)

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  First chip card from Giesecke & Devrient (1979)

Homage

“Helmut Gröttrup was an engineer who was deeply convinced of his work. [...] I honestly have to admit that I liked him as a person and as a talented engineer. He had this 'divine spark'. "

- Boris Tschertok : Rockets and People (Volume 1), p. 248

“They succeeded in getting H. Gröttrup, who was disappointed by the Americans, to be interested in their plans. This electronics engineer, who was 30 years old at the time, had also gained a very broad overview of the current state of rocket technology in Peenemünde [...]. His friendly, open nature, his quick comprehension and ability to combine ideas and finally his organizational talent made Gröttrup a key figure in the missile development group planned by the Soviets. "

- Kurt Magnus : Rocket Slaves, p. 20

“In all stages of his career, his work was characterized by human warmth, exemplary sense of duty, high intellect, excellent skills both in the organizational area and in leading employees, which he knew how to motivate to high performance. [...] His education, the diverse experiences and his wide-ranging physical knowledge in connection with his special talent for solving theoretical tasks and the extraordinary skill for organization and leadership opened up a new fascinating field of work for him: the evolution and revolution of society, economy and the credit industry significant payment systems. "

- Obituary in the magazine "Geldinstitute", July 1981

“With his rocket construction philosophies, Helmut Gröttrup placed a treasure in the hands of the Soviet designers, which led to a rocket cell construction that [...] still flies successfully in every SOYUS rocket version today. With every launch this rocket proves the genius of the complex constructive work of Germans in the USSR. "

- Olaf Przybilski : From rockets to chip cards, p. 7, February 2017

“Gröttrup had helped to lay the basis for the later first major steps in Soviet space travel, their initial leadership position in the direction of the moon. The great triumph was denied him. […] Helmut Gröttrup was left with another life's work: he later invented the chip card and had it patented. He could not win the race to the moon, but revolutionized, accelerated and simplified the payment of bills worldwide, the access of authorized persons to exclusive areas, the handling of ID cards for the library, for the health insurance company, for the ATM. Many say this was a bigger leap for mankind than victory in the space race. "

- Ulli Kulke : Weltraumstürmer, p. 137

“Gröttrup had the gift of being able and willing to listen . Gröttrup listened, thought about what they had heard and dismissed his interlocutors with good tips and highly motivated. He had the gift of a teacher with young people who do not yet know that they are learning for themselves, but often learn for the teacher if they like him. [...] And that could have been what Chertok meant with his "divine spark". "

- Reinhard Weißgerber : Speech on the 100th birthday of Gröttrup (unpublished)

Publications

• Helmut Gröttrup: A new coincidence device for documentation: Contribution to the technique of mechanical selection with punch cards . In: German Society for Documentation (Hrsg.): Rational documentation technology . tape 1 , 1955 (16 pages).
• Helmut Gröttrup: Study analysis of semi-automatic documentation selectors . In: Research reports from the North Rhine-Westphalia Ministry of Economics and Transport . No. 604 . Springer Fachmedien, Wiesbaden 1956, ISBN 978-3-663-03744-6 (112 pages).
• Helmut Gröttrup: About rockets. A comprehensible introduction to the physics and technology of the rocket . Ullstein, Berlin 1959, DNB  451676866 (244 pages).
• Hans Bolewski; Helmut Gröttrup (Ed.): The space in human hands . With a foreword by Irmgard Gröttrup. Kreuz-Verlag, Stuttgart 1959, DNB  455453322 (238 pages).
• Helmut Gröttrup: Technology and importance of long-range ballistic missiles . In: Hans Bolewski, Helmut Gröttrup (ed.): The world space in human hands . Kreuz-Verlag, Stuttgart 1959, p. 82–94 : "So it is not difficult to recognize that the non-military tasks of the missile have not yet received sufficient support and that desires for sensible support for research tasks that can be solved with missiles are justified."

literature

• Asif Azam Siddiqi: Challenge to Apollo: The Soviet Union and the Space Race, 1945–1974 . NASA, Washington 2000 (English, 1028 pages).
• Werner Albring: Gorodomlia. German rocket researchers in Russia . Luchterhand Literaturverlag, Munich 1991, ISBN 978-3-630-86773-1 (260 pages).
• Kurt Magnus: Rocket Slaves. German researchers behind red barbed wire . Elbe-Dnjepr-Verlag, Mockrehna 1999, ISBN 978-3-933395-67-2 (360 pages).
• Boris E. Chertok: Rockets and People . German missiles in Soviet hands. tape 1 . Elbe-Dnjepr-Verlag, Mockrehna 1998, ISBN 978-3-933395-00-9 (492 pages).
• Ulli Kulke: Space striker: Wernher von Braun and the race to the moon . Quadriga, Berlin 2012, ISBN 978-3-86995-026-6 (288 pages).
• Sharon Dodua Otoo : Mr. Gröttrup sits down. (PDF; 111 kB) Bachmann Prize 2016. July 2, 2016, accessed on May 13, 2019 . 

Web links

• Helmut Gröttrup in the Encyclopedia Astronautica , accessed on May 13, 2019 (English).

Individual evidence

1. ↑ ^{a b} Horst Böttge; Alfred Schmidt: From rockets to chip cards - on the 100th birthday of Helmut Gröttrup. (PDF; 2.65 MB) Event in the hall of honor of the Deutsches Museum in Munich. February 3, 2017, accessed May 16, 2019 . 
2. ^ Michael J. Neufeld: Wernher von Braun. Visionary of space, engineer of war . 1st edition. Siedler, Munich 2009, ISBN 978-3-88680-912-7 , p. 205-210 (687 pp. American English: Von Braun. Dreamer of Space, Engineer of War . New York 2007. Translated by Ilse Strasman).
3. ^ Walter Dornberger : V2 - The shot into space. Story of a great invention . Bechtle, Esslingen 1952, p. 224–225 (296 pages): “After a visit to Stettin, in close cooperation with Major Klamroth, we succeeded in getting Professor von Braun to Schwedt after a few days and then completely free. [..] A little later I was able to welcome Riedel and Gröttrup to my office. "
4. ↑ David Irving : Company Crossbow. (PDF; 2.5 MB) The fight of the British secret service against Germany's miracle weapons. Der Spiegel, November 17, 1965, accessed on April 22, 2019 . 
5. ^ ^{A b} Manfred Bornemann : Secret Project Mittelbau . Bernard & Graefe, 1994, ISBN 978-3-7637-5927-9 (238 pages).
6. ↑ Bernd Henze: Rocket research: From Witzenhausen to the moon. Why the Soviet flag was almost the first to fly on the earth's satellite. (PDF; 13.7 MB) In: Ostpreußenblatt. July 24, 1999, p. 20 , accessed on September 12, 2019 : “In the Collmann house of the colonial school, closely guarded by the US Army, 80 people from Peenemünde were initially killed by v. Braun quartered. " 
7. ↑ Werner Albring: Research and development problems of rockets, processed in a hermitage on the island in the Seligersee (1946 to 1952) . Lecture at the meeting of the technical science class on September 25, 1998. Ed .: Berlin-Brandenburg Academy of Sciences. Akademie-Verlag, Berlin, ISBN 3-05-003321-5 (15 pages).
8. ↑ Boris E. Tschertok: Rockets and people . German missiles in Soviet hands. tape 1 . Elbe-Dnjepr-Verlag, Mockrehna 1998, ISBN 978-3-933395-00-9 (492 pages).
9. ↑ ^{a b c d} Matthias Uhl : Stalin's V-2. The technology transfer of German radio controlled weapons technology to the USSR and the development of the Soviet missile industry from 1945 to 1959 . Dissertation with reproduction of many original documents. Bernard & Graefe Verlag, Bonn 2001, ISBN 978-3-7637-6214-9 (304 pages).
10. ^ ^{A b} Paul Maddrell: Spying on Science: Western Intelligence in Divided Germany 1945-1961 . Ed .: Oxford University Press. 2006, ISBN 978-0-19-926750-7 (English, 344 pages): “An unsuccessful attempt had even been made to entice Helmut Gröttrup to leave his job as director of the Institut Rabe at Bleicherode and take up work in Britain . ”
11. ^ Anatoly Zak: News and history of astronautics in the former USSR - German team on Moscow. Retrieved December 1, 2016 . 
12. ^ Anatoly Zak: News and history of astronautics in the former USSR - German team on Gorodomlya Island. Retrieved December 1, 2016 . 
13. ↑ Anatoly Zak: Tests of the A-4 rocket in Kapustin Yar. Retrieved on August 26, 2019 : "The first launch of the A-4 rocket designated No. 010T, which was preceded by a short delay caused by a failure of the ignition system. Three Russian technicians run to a fully loaded rocket and replaced pyrotechnic device initiating the launch. The vehicle blasted off on October 18, 1947, at 10:47 Moscow Time and after a short arc into the stratosphere impacted 206.7 kilometers from the launch site deviating around 30 kilometers to the left from the target. Absence of a large crater at the impact site showed that the rocket apparently disintegrated before crashing. Still, the launch was qualified as a success. " 
14. ↑ G-1 in the Encyclopedia Astronautica , accessed on May 14, 2019. - G-1 as a draft for R-2
15. ↑ G-4 in the Encyclopedia Astronautica, accessed on May 14, 2019. - G-4 as a draft for R-3, R-10 and R-14
16. ^ Anatoly Zak: History of the Gorodomlya Island. Beginning of the end. August 5, 2012, accessed August 26, 2019 . 
17. ↑ Paul Maddrell: Gateway to the Soviet Union. (PDF; 1.9 MB) The occupation of Germany and the spying of the USSR by the British intelligence service. In: Institute for Contemporary History. February 1, 2003, accessed on May 11, 2019 : “The Gröttrup group's R-14 draft for a rocket that was supposed to carry a load of 3,000 kilograms up to 3,000 kilometers also confirmed the Soviet determination to grant long-range rockets to build." 
18. ↑ Olaf Przybilski: How the USSR assimilated the German rocket aggregate 4. (PDF, 129 kB) In: Luft- und Raumfahrt 2/2006, p. 44 February 2006, accessed on May 3, 2019 . 
19. ↑ Development of guided missiles at Bleicherode and Institut 88. (PDF; 1.1 MB) In: CIA Historical Collections . January 22, 1954, accessed on August 24, 2019 (English, extensive summary of the work results of the German collective in NII-88): “Besides this love for rocket technique, there exists a second mental consideration which affects Soviet decisions, and that is respect for work in the West, especially German work. Data emanating from Germany were regarded as almost sacrosanct. " 
20. ^ Anatoly Zak: German contribution in the Soviet rocketry: Myth and Reality. August 12, 2012, accessed on May 11, 2019 (English): "striking resemblance between a cone-like aerodynamic shape proposed by the Gröttrup team for several of its rockets and Korolev's own designs, which appeared in metal years later. Korolev's largest rockets - the R-7 and the ill-fated N1 moon rocket, both featured exotic conical shape " 
21. ↑ Boris Tschertok; Ursula Gröttrup: Course Peenemünde. (PDF; 790 kB) with a letter to the editor from Ursula Gröttrup to correct some allegations. Raumfahrt Concret, June 1999, accessed on May 17, 2019 . 
22. ↑ Irmgard Gröttrup: The possessed and the mighty. In the shadow of the red rocket . Steingrüben Verlag, Stuttgart 1958, OCLC 73419520 (260 pages).
23. ↑ This epilogue is very likely from Helmut Gröttrup himself, although Irmgard Gröttrup does not explicitly identify him as the author.
24. ↑ Ex-German Rocket Scientists. US rocket program 1969. (Video; 6:36 min) In: youtube. Thames Television, July 17, 1969, accessed January 29, 2020 . 
25. ↑ The birth of computer science. Heinz Nixdorf Forum (HNF) Blog, July 2, 2018, accessed on May 16, 2019 : "In 1956, we also had IT, at least as a word: It was in the Stuttgart IT plant of Standard Elektrik AG." 
26. ↑ Office automation: The brain. (PDF; 631 kB) In: Der Spiegel . May 3, 1958, accessed August 14, 2020 . 
27. ↑ Patent DE1524695 : Identification switch . Registered on December 6, 1966 , published on November 26, 1970 , applicant: Tankbau Weilheim AG, inventor: Helmut Gröttrup. ‌
28. ↑ Patent DE1574074 : Counterfeit-proof identification switch . Registered on February 6, 1967 , published on November 25, 1971 , applicant: Intelectron Patentverwaltung GmbH, inventor: Helmut Gröttrup. ‌
29. ↑ Patent DE1574075 : Identification switch with inductive assignment. Registered on February 6, 1967 , published on November 25, 1971 , applicant: Intelectron Patentverwaltung GmbH, inventor: Helmut Gröttrup. ‌
30. ↑ Patent DE1945777C3 : Identification switch . Registered on September 10, 1969 , published on April 1, 1982 , inventors: Jürgen Dethloff, Helmut Gröttrup. ‌
31. ↑ Poster gallery DPMA 2014_No. 33: Chip card from Jürgen Dethloff and Helmut Gröttrup [1]
32. ↑ The Chip Citizen - Everything on one card. (PDF; 662 kB) Der Spiegel 47/1994, November 21, 1994, accessed on May 17, 2019 (link shows the cover picture of Spiegel; PDF of the article can be downloaded from this page). 
33. ^ Norbert Pötzl: Everything on one card. The chip card turns 50. Spiegel Online, September 13, 2018, accessed on May 16, 2019 : “Without this piece of plastic, little works in everyday life, chip cards penetrate our lives like hardly any other technical innovation. And who invented it? Two German inventors, in 1968. " 
34. ↑ ^{a b c} Jan Hendrik Prell; Horst Böttge: Giesecke & Devrient 1852–2002. Values ​​through the ages . Ed .: Giesecke & Devrient. Deutscher Sparkassen Verlag, Stuttgart 2002, ISBN 978-3-09-303892-1 .
35. ↑ Horst Böttge; Tobias Mahl; Michael Kamp: From the ec card to Mobile Security 1968–2012 . Ed .: Giesecke & Devrient. Battenberg Gietl Verlag, Munich 2013, ISBN 978-3-86646-549-7 (German, English, 248 pages).
36. ↑ Counterfeit money. (PDF; 308 kB) The Bundesbank wants to track down counterfeiters with a super computer. Der Spiegel 6/1977, January 31, 1977, accessed on May 16, 2019 (link shows the cover picture of Spiegel; PDF of the article can be downloaded from this page). 
37. ↑ Hartmut Petzold: Annual Report 2006 (PDF; 4.24 MB) Deutsches Museum, 2007, p. 24 , accessed on July 23, 2019 . 
38. ^ History of Currency Counting at the Federal Reserve Bank of Philadelphia. The 1990s: State of the Art Security. In: Federal Reserve Bank of Philadelphia. Retrieved July 24, 2019 .