Dr. Hildegard Gertrud Helen Korf Kallmann-Bijl (1908-1968) was one of the most active pioneers in her examination of the physics of high atmosphere for the flight calculations of satellites. Before the first satellite reached its orbit, she had calculated a theoretical extrapolation of a model of the atmosphere which gave physicists a whole year's lead. The lifespan of the satellite could be predicted with the "Kallmann Atmosphere." Dr. Kallmann then made satellite measurements in relation to this atmospheric model, again to perfection. In 1961, she published a paper on the International Reference Atmosphere. With this foundation, she was able to forecast the landing spot with accurate precision for the astronauts and cosmonauts.
Hildegard Korf was born on September 18, 1908 in Gelsenkirchen, Germany. She was raised in the Catholic faith and educated in Catholic boarding schools. By 1929, Ms. Korf had earned the equivalent of her bachelor's degree at the University of Berlin, in Philosophy. She then enrolled in classes at the Technische Hoch Schule and majored in Metallurgy. While attending school, Ms. Korf volunteered her free time to work for the Journalism Institute at the University of Berlin where she gained experience in the editorial business. She later worked three years as an editor for the Deutscher Press Publishers.
While at the university, Hildegard Korf became friends with Julie Braun. It was she who developed in Ms. Korf a sensitivity for Goethe and the worlds of science and art. However, Julie Braun was forced to leave Germany because of her Jewish faith. The Korfs were not persecuted because they were considered three quarters "Aryan" and one quarter "non-Aryan," but by the 1930's the Korfs were not allowed full political freedom. Julie Braun left her estate in Zehlendorf in the care of Ms. Korf and her attorney, Curt Kallmann. There was little Curt Kallmann could do to protect Julie's property because he too was Jewish. One evening in 1939, Kallmann called Hildegard Korf and told her that the Gestapo was on their way to arrest him. With the help of Dr. Benno Hahn, Ms. Korf was able to get herself and Curt Kallmann out of Germany and on their way to Sweden. The Dresden Zeiss Works, where Ms. Korf had worked since 1936, asked her to return and "guaranteed" that no action would be taken against her, but Hildegard Korf felt that she had burned her bridge behind her and never went back to Germany. Kallman suffered a nervous breakdown while in Sweden, and since he was unable to travel alone to the United States, the American Council suggested to Ms. Korf that she travel as his wife. Because of laws existing then, it took an intervention of a Catholic Bishop in Sweden to bring about their marriage. They made the journey to America and their marriage lasted until 1958. Dr. Hildegard Kallmann divorced Curt Kallman but continued to support him until her death.
Dr. Hildegard Kallmann later married Jan Bijl, a Dutchman who had spent several years in a German concentration camp for acting as a Dutch courier while in exile in London. At the time of their marriage, Bijl was the Vice-President of Fokker Aviation at Shiphol near Amsterdam. Unfortunately, Jan Bijl died on December 9, 1963. Dr. Hildegard Kallmann-Bijl died suddenly of a heart attack on November 7, 1968.
Between the years of 1949-1963, Dr. Kallmann-Bijl published approximately 35 papers on ionospheric research, meteor research, high altitude research, solid propellant research, national space research and international space research. Dr. Kallmann-Bijl will always be remembered for her contributions in early astrophysical studies at national and international laboratories.