of Opel-RAK program, Valier eventually was killed while experimenting with liquid-fueled rockets as means of propulsion in mid-1930, and is considered the first fatality of the dawning space age. In 1930, von Braun attended the Technische Hochschule Berlin, where he joined the Spaceflight Society (Verein für Raumschiffahrt or "VfR"), co-founded by Valier, and worked with Willy Ley in his liquid-fueled rocket motor tests in conjunction with others such as Rolf Engel, Rudolf Nebel, Hermann Oberth or Paul Ehmayr. In spring 1932, he graduated with a diploma in mechanical engineering. His early exposure to rocketry convinced him that the exploration of space would require far more than applications of the current engineering technology. Wanting to learn more about physics, chemistry, and astronomy, von Braun entered the Friedrich-Wilhelm University of Berlin for doctoral studies and graduated with a doctorate in physics in 1934. He also studied at ETH Zürich for a term from June to October 1931. Career in Germany In 1930, von Braun attended a presentation given by Auguste Piccard. After the talk, the young student approached the famous pioneer of high-altitude balloon flight, and stated to him: "You know, I plan on traveling to the Moon at some time." Piccard is said to have responded with encouraging words. Von Braun was greatly influenced by Oberth, of whom he said: According to historian Norman Davies, von Braun was able to pursue a career as a rocket scientist in Germany due to a "curious oversight" in the Treaty of Versailles which did not include rocketry in its list of weapons forbidden to Germany. Involvement with the Nazi regime Nazi Party membership Von Braun had an ambivalent and complex relationship with Nazi Germany. He applied for membership of the Nazi Party on 12 November 1937, and was issued membership number 5,738,692. Michael J. Neufeld, an author of aerospace history and chief of the Space History Division at the Smithsonian's National Air and Space Museum, wrote that ten years after von Braun obtained his Nazi Party membership, he signed an affidavit for the U.S. Army, though he stated the incorrect year: In 1939, I was officially demanded to join the National Socialist Party. At this time I was already Technical Director at the Army Rocket Center at Peenemünde (Baltic Sea). The technical work carried out there had, in the meantime, attracted more and more attention in higher levels. Thus, my refusal to join the