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D.K. Yeomans (JPL/Caltech)
Until a few decades ago, interplanetary travel was the stuff of dreams but the dreamers often turned out to be farsighted while the predictions of some eminent scientists were far too conservative. The prescient dreamers include the Russian schoolteacher, Konstanin Tsiolkovsky who, in 1883, was the first to note that only rockets could serve the needs of space travel. In 1923, Herman Oberth published a treatise discussing various aspects of interplanetary travel including the impulse necessary to escape the Earth's gravitational pull. In his spare time, a German civil engineer, Walter Hohmann, established in 1925 that the optimal energy transfer orbit between planets is an ellipse that is tangent to the orbits of both bodies. Four year later, an Austrian army officer, Hermann Potocnik outlined the benefits of space stations including those in geosynchronous orbits. Whereas Tsiolkovsky, Oberth, Hohmann, and Potocnik provided ideas and theories, the American, Robert H. Goddard, was testing liquid fueled rockets by as early as 1925. By the time he was finished in 1941, Goddard flew liquid fueled rockets that reached speeds of 700 mph and altitudes above 8,000 feet. In direct contrast to the advances by these mostly amateur engineers, many respected authorities scoffed at space travel because of the insurmountable technological difficulties. One year prior to the launch of Sputnik, the British Astronomer Royal, Sir Richard Wooley, declared, "space travel is utter bilge." While the theories of space travel were well developed by the late 1920's, space travel technology was still a poorly funded, mostly amateur, endeavor until the German army hired Oberth's student, Werner von Braun, and others to develop long range rockets for military purposes. In the early 1940's, Von Braun's team developed the rocket propulsion and guidance systems that would one day form the basis of the American space program.
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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.