Pioneers of Twentieth Century Rocketry
In the early 1900s there was a rise of experimentation with rocket motors using liquid rather than solid fuel. Three rocket scientists were at the forefront of this research – Konstantin Tsiolkovsky in the Soviet Union, Hermann Oberth in Germany, and Robert Goddard in New Mexico. Goddard had the greatest impact and, prior to the German V-2 program, made the most significant discoveries. His work was financially supported by the Guggenheim Aeronautical Laboratory at California Institute of Technology (CALTECH). As the “father” of the first working rocket, his work was instrumental in everything that followed. Oberth’s mathematical calculations and support played an important role in the early work of the later German rocket team as well. But first…who was Pedro Paulet?
Pedro A. Paulet was a Peruvian chemical engineer and diplomat. Though he failed to report on his work until October 1927 in Lima’s El Comercio newspaper, he conducted experiments with liquid-fueled rockets as early as 1895. His rocket motor was small, made of vanadium steel, and was capable of producing up to 200 pounds of thrust. Paulet was forced to discontinue his work because of economic trouble and “his neighbor’s complaints.” His rocket motor was significant as it was fueled by a mixture of nitrogen peroxide and gasoline, with a spark gap in the combustion chamber providing ignition. The motor itself weighed just over 5 pounds, producing its thrust at 300 explosions a minute.
By 1901, Paulet had joined the Peruvian diplomatic corps, being posted in Paris and later Antwerp, while continuing various scientific pursuits. He died in 1945, at the age of 70. Should Paulet rightly be called the “Father of Modern Rocketry?” Wernher von Braun certainly thought as much.
Paulet would have been largely forgotten had it not been for Russian scientist Alexander Scherschevsky, who learned of the article while living in Germany and summarized it in his book “The Rocket for Travel and Flight” published in 1929. The publication of works by both Robert Goddard and Hermann Oberth sparked the imagination and interest of scientists and engineers throughout Europe. In response to this, Paulet wrote his letter to the paper to claim credit – legal and otherwise – for this new innovation in science, it was a plea for recognition of the work he had done decades earlier while a student at the Institute of Applied Chemistry in Paris. Fearing he would not be believed, he called upon his former friends and colleagues in Paris to verify his experimental work, but could find no witnesses for his legal claims to being the inventor of a liquid-fueled rocket motor.
Born in Russia in 1857, Tsiolkovsky’s original interest in rocketry came from his philosophical work on human interactions in colonizing space. A physicist and mathematician, his research was broad and included gas dynamics and mathematical models for space travel, and in May 1903, he published “Exploration of Outer Space by Means of Rocket Devices,” his most famous work. In it, he details using liquid-fueled, multi-stage rockets, and was the first to independently calculate the “Ideal Rocket Calculation,” known as the “Tsiolkovsky Equation.” This formula was also independently reached by Robert Goddard in 1912, and Hermann Oberth by 1920. The Tsiolkovsky equation states that the horizontal speed required for an orbit of the Earth is 8000 meters/second, or about 5 miles per second. A multi-stage rocket fueled by liquid oxygen and hydrogen could accomplish this, with each stage being released as its fuel load burned out, lightening the rocket in the process.
Tsiolkovsky continued his research and design interests throughout his life, and many of his theoretical designs and calculations became an important part of modern rocket design: the use of fuel as a cooling mechanism for combustion chambers, graphite or carbon vanes and exhaust vectoring for flight control, development of numerous fuel/oxidizer combinations for the greatest efficiency in combustion, a chemically-driven pump system to provide fuels for the combustion chamber, and calculating the required trajectory for a craft to enter Earth’s atmosphere and return from space.
Tsiolkovsky died in 1935, never seeing one of his rockets built and launched, but his equations and many of his ideas became critical in the future success of other rocket engineers.
Born in 1894 in Hermannstadt, Transylvania (now Sibiu, Romania) Hermann Oberth was inspired at the age of eleven by the works of novelist Jules Verne, and at age 14 built his first model rocket. Drafted into the Imperial German Army at the outbreak of World War I, by 1915 he was posted to a medical unit in Romania and in his spare time designed rockets. In 1917, he send a proposal to the German War Department regarding the use of large, liquid-fueled long range rockets for use in bombardment – a proposal which was rejected. In 1922, he proposed the same, again to the German government, but with the introduction of their possible use as a vehicle for space flight so as to not cause concerns over violations of the 1919 Versailles Treaty.
The year 1922 was a crucial year for the young scientist, as his proposed dissertation idea was dismissed as “utopian;” he was urged to come up with a different topic. Rejecting this recommendation, he later said “I refrained from writing another one, thinking to myself: Never mind, I will prove that I am able to become a greater scientist than some of you.” The proposal was published as the 92-page The Rocket into Planetary Space, a ground-breaking work, but one which caused Oberth a bit of consternation. Only a few years previously Robert Goddard had published his first – seminal – work, A Method of Reaching Extreme Altitudes. To avoid the implication that his work was “inspired” by Goddard’s, Oberth included a three page addendum, urging readers to study both to see that Oberth had come to his conclusions separately.
By 1929, Oberth had expanded his earlier work into the 400-page publication titled “The Road to Space Travel” and worked tirelessly to promote his ideas of using rockets to go into space. That same year, he became president of the VfR – Verein für Raumschiffahrt, or Spaceflight Society. Due to his publications and reputation he became an important mentor to many of the young scientists and engineers of the VfR, and was approached by the UFA Film Company. Director Fritz Lang was planning his movie “Frau im Mond” (The Girl in the Moon) and an idea for a publicity stunt was born. Oberth, with his assistants Rudolf Nebel and Alexander Scherschevsky, designed a rocket called “Kegelduse.” The rocket was built in a space acquired for the project at the Reich Institution of Chemical Technology by Klaus Riedel and a young 18 year old assistant – Wernher von Braun. Static tested in July 1930, money for the project soon dried up and Oberth was forced to leave the VfR and return to teach in Romania.
The next few years saw Oberth move many times – from Romania to Germany, Austria and the United States before finally returning to teach in Dresden, Germany in 1938. By 1941, he joined the German rocket team at the Aggregate rocket research, development and test center at Peenemunde. When the war ended in 1945, Oberth traveled to Nuremberg, in the US Zone of occupation, before moving to Switzerland and later Italy. By the late 1950’s he had moved to Redstone Arsenal, Alabama and joined the main group of German rocket scientists who were brought to the US under “Operation Paperclip” and were now doing development work for the US Army. In 1960, Oberth took a job as a technical consultant with the Convair Corporation on the Saturn V rocket program before retiring and moving back to Germany in 1962. In 1969, he returned to view the launch of Apollo 11, then returned again in 1985 to observe the ill-fated launch of Space Shuttle Challenger during the STS-41 mission. Oberth returned to Nuremberg, Germany one last time, where he died in December 1989.