Eugen Sänger was an Austrian aerospace engineer. He was born on September 22, 1905, and died on February 10, 1964. He is best known for his work on lifting body and ramjet technology.

Early career

Sänger was born in the former mining town of Preßnitz (Přísečnice), near Komotau in Bohemia, which was part of the Austro-Hungarian Empire at that time. He studied civil engineering at the Technical Universities of Graz and Vienna. While a student, he read Hermann Oberth's book Die Rakete zu den Planetenräumen ("By Rocket into Planetary Space"), which inspired him to switch from studying civil engineering to aeronautics. He also joined Germany's amateur rocket group, the Verein für Raumschiffahrt (VfR – "Society for Space Travel"), which was centered on Oberth.

In 1932, Sänger became a member of the SS and also joined the NSDAP.

Sänger made rocket-powered flight the focus of his thesis, but the university rejected it, calling it too imaginative. He was allowed to graduate only after submitting a much simpler paper on the statics of wing trusses. Later, he published his rejected thesis under the title Raketenflugtechnik ("Rocket Flight Engineering") in 1933. In 1935 and 1936, he wrote articles about rocket-powered flight for the Austrian journal Flug ("Flight"). These articles caught the attention of the Reichsluftfahrtministerium (RLM, or "Reich Aviation Ministry"), which believed Sänger's ideas could help build a bomber capable of attacking the United States from Germany (the Amerikabomber project). The RLM gave him a research institute near Braunschweig and built a liquid oxygen plant and a test stand for a 100-tonne thrust engine. At the time, Sänger's hiring was opposed by Wernher von Braun, who believed his own work was being copied and may have seen Sänger as a threat to his influence in the field.

Sub-orbital bomber concept

In 1936, Sänger agreed to lead a rocket development team in the Lüneburger Heide region. He began designing a rocket-powered sled that would launch a bomber equipped with its own rocket engines. This bomber would climb to the edge of space and then travel through the upper atmosphere in a series of short trips, without entering orbit. This design, called the Silbervogel ("Silverbird"), relied on the plane’s body to create lift, allowing it to follow a path through space. Sänger worked with mathematician Irene Bredt, whom he married in 1951, to develop this design. He also created the rocket engines needed for the space-plane, which required producing 1 meganewton (225,000 lbf) of thrust. Sänger was among the first to suggest using rocket fuel to cool the engine by circulating it around the nozzle before burning it.

By 1942, the Reich Air Ministry canceled the Silbervogel project along with other complex and theoretical designs, choosing instead to focus on proven technologies. Sänger was then assigned to work at the Deutsche Forschungsanstalt für Segelflug (DFS, or "German Gliding Research Institute"). There, he contributed to advancements in ramjet technology, including projects like the Skoda-Kauba Sk P.14 interceptor, until the end of World War II.

Postwar

After the war ended, Sänger worked for the French government and started the French Astronautical Federation in 1949. While in France, he was the target of a failed attempt by Soviet agents to persuade him to join the Soviet Union. Joseph Stalin had become interested in reports about the Silbervogel design and sent his son, Vasily, and scientist Grigori Tokaty to convince him to move to the Soviet Union, but they were unsuccessful. It has also been reported that Stalin ordered the NKVD to kidnap him.

In 1951, he became the first president of the International Astronautical Federation. That same year, he married Dr. Irene Bredt, his first assistant. She was a German engineer, mathematician, and physicist who helped design a proposed spaceplane that could travel long distances.

By 1954, Sänger returned to Germany and, three years later, led a jet propulsion research institute in Stuttgart. Between 1961 and 1963, he worked as a consultant for Junkers to design a ramjet-powered spaceplane, but the project remained only on paper. In 1963, he became a professor at Technische Universität Berlin, where he worked until his death. During this time, he also proposed using light particles to move spacecraft between planets and stars, ideas that foreshadowed the concepts of laser propulsion and solar sails.

In 1960, he helped the United Arab Republic develop the Al-Zafir missile. He died in Berlin in 1964. Sänger’s grave is located in the "Alter Friedhof" cemetery in Stuttgart-Vaihingen. His work on the Silbervogel design influenced the X-15, X-20 Dyna-Soar, and Space Shuttle programs. The Saenger spaceplane concept was named after him.

Honours

Honorary member of many groups that study space in Germany, Great Britain, Austria, the United States of America, Norway, Sweden, Switzerland, Argentina, and Italy.

• Received the title of Honorary Fellow of the British Interplanetary Society (B.I.S.) in 1949
• Received the Hermann Oberth Medal for contributions to aerospace research
• Awarded the Austrian Cross of Honour for Science and Art, First Class
• Named Commander of the Ordre du Merite pour la Recherche et l'Invention in Paris
• Received the Gagarin Gold Medal from Associazione Internazionale Uomo nello Spazio in Rome
• Won a Gold Medal at the Milan Fair
• A street named Sängergasse in Vienna's Simmering district (11th District) was named in his honor in 1971

References and further reading

• Sänger, Eugen (1956). Zur Mechanik der Photonen-Strahlantriebe. Published by R. Oldenbourg in Munich. Page 92.
• Sänger, Eugen (1957). Zur Strahlungsphysik der Photonen-Strahlantriebe und Waffenstrahlen. Published by R. Oldenbourg in Munich. Page 173.
• Sänger, Eugen (1933). Rocket Flight Engineering. Published by NASA Tech. Trans. F-223 in Washington, 1965. {{ cite book }}: CS1 maint: location (link).
• Sänger, Eugen; Irene Sänger-Bredt (August 1944). "A Rocket Drive For Long Range Bombers" (PDF). Published by Astronautix.com. Saved from the original PDF on June 14, 2006. Retrieved on January 17, 2008.
• Saenger, Hartmut E and Szames, Alexandre D, From the Silverbird to Interstellar Voyages, IAC-03-IAA.2.4.a.07.
• Sänger, Eugen; translated by Karl Frucht (1965). Space Flight: Countdown for the Future. Published by McGraw-Hill in New York.
• Dressel, Joachim & Griehl, Manfred (January 1990). "Un bombardier spatial… en 1940" [A Space Bomber… in 1940]. Published in Le Fana de l'Aviation (in French) (242): Pages 35–38. ISSN 0757-4169.
• Duffy, James P. (2004). TARGET: AMERICA: Hitler's Plan to Attack the United States. Published by Praeger. ISBN 0-275-96684-4.
• Shayler, David J. (2005). Women in Space – Following Valentina. Published by Springer. ISBN 1-85233-744-3.

• Westman, Juhani (2006). "Global Bounce." Saved from the original on October 9, 2007. Retrieved on January 17, 2008.
• Wade, Mark. "Eugen Albert Saenger." Published by Astronautix.com. Saved from the original on October 13, 2007. Retrieved on January 17, 2008.