In 1931, von Braun interrupted his studies at the Institute of Technology in Berlin to study for a semester at the Federal Institute of Technology in Zurich. He returned to Berlin in October for the first public firing of Riedel's rocket. Several local industrialists had been persuaded by Nebel and Riedel to pay one mark each to witness the demonstration. When the moment of truth came, the rocket moved halfway up the launcher tracks, then settled peacefully back on the pad. What an embarrassment, but the admission fees were not returned! The pressurization of the rocket's fuel tanks was unreliable and this problem was soon corrected. Within a few weeks, successful launchings became commonplace and the rocket reached an altitude of 1,000 feet. A small parachute carried the tail section gently back to Earth. Riedel would dash across the field in an old car, jump out, and sometimes catch the rocket before it struck the ground. After such a lucky "hand recovery," they could fire the rocket again immediately.
While taking part in these exciting activities in his spare time, von Braun continued with his formal studies, and graduated from the Berlin Institute of Technology with a bachelor's degree in aeronautical engineering in 1932. During vacation periods between 1931 and 1933 he took flying lessons and gained a private pilot's license.
Von Braun's exposure to rocketry convinced him that the exploration of space would require far more than just applications of the current engineering technology. To this end he enrolled as a graduate student at the University of Berlin and gained his Ph.D. in physics in 1934. His thesis was about liquid rocket propulsion. Solid propellant rockets had been used for centuries, but liquid propulsion was new. Only miniature motors had been built and tested that used a liquid oxygen/alcohol propellant combination. Von Braun wanted to analyze some of the puzzling phenomena that take place in a rocket engine, such as atomization, combustion, and expansion of gases. Experimentation would be costly and von Braun considered himself fortunate when the research department of the German Army Ordnance Corps sponsored his research and permitted him to conduct dangerous experiments at the Kummersdorf Army Proving Ground.
After gaining his Ph.D., von Braun became a civilian employee of the Army and continued with this work. He designed the V-2 rocket that was used so effectively against Britain during World War II. At the end of the war, the von Braun team at Peenemunde on the Baltic Sea headed south and surrendered to U.S. forces rather than risk capture by the Soviet army.