Research Notes on Hermann Oberth

“To boldly go where no man has gone before.” – Hermann Oberth

Hermann Oberth’s theoretical breakthroughs transformed rocketry from speculative fiction into science, thus influencing the development of modern space exploration. His mentorship of Wernher von Braun and contributions to the V-2 rocket program set foundational principles that shape the field.

Germany’s major figure in early rocketry, Oberth held a place alongside Russia’s Konstantin Tsiolkovsky and the United States’ Robert H. Goddard. Born on July 25, 1894, in Hermannstadt, Transylvania (now Sibiu, Romania), Oberth was captivated by space from an early age, drawing inspiration from Jules Verne’s science fiction, notably “From the Earth to the Moon” and “Around the Moon.” Initially pursuing medicine in Munich, he served as a medic in World War I, during which he developed an interest in rocketry. Oberth proposed liquid-fueled rockets as a means for long-range missiles to the German War Department, though his ideas were dismissed.

In 1922, Oberth formalized his concepts in his doctoral dissertation, “Die Rakete zu den Planetenräumen” (“By Rocket into Planetary Space”), which the University of Heidelberg rejected as speculative. Undeterred, Oberth self-published in 1923. His research demonstrated that rockets could reach outer space, detailed the feasibility of liquid propellants – liquid oxygen and hydrogen, proposed multi-stage rockets for increased velocities, and addressed challenges in space navigation and life support.

To advance Oberth’s vision, the Verein für Raumschiffahrt (VfR), or German Society for Space Travel, was established in 1927. The VfR, drawing scientists and engineers eager to make space travel a reality, began conducting experimental rocket tests by 1929. The society attracted notable members, including Wernher von Braun, a young engineering student who became Oberth’s assistant and protégé, as well as Rudolf Nebel, a pivotal figure in early rocketry. The VfR’s activities inspired similar organizations globally, including the American Rocket Society.

Oberth’s mentorship influenced von Braun, who later directed Germany’s rocket development efforts during World War II. Together, Oberth and von Braun worked on liquid-fueled rockets to achieve high-altitudes, accelerating Germany’s rocketry program. Leveraging Oberth’s theories, Germany developed the V-2 rocket, the world’s first long-range guided ballistic missile.

The legacy of Oberth’s work is clear: the V-2’s technology became the blueprint for postwar rocketry. In the United States, von Braun’s Saturn V rocket launched the Apollo missions to the Moon. In the Soviet Union, captured V-2 technology supported early rocket development. All modern rockets trace their lineage to the V-2 and to Oberth’s pioneering contributions.

References

  • Anderson, M. (Ed.). (2012). Pioneers in Astronomy and Space Exploration. Britannica Educational Publishing.
  • Oberth, H. (1984). Die Rakete zu den Planetenräumen. Oldenbourg Wissenschaftsverlag.
  • Neufeld, M. J. (1995). The rocket and the Reich: Peenemünde and the coming of the ballistic missile era. Simon and Schuster.

A Possible High-Re Liquid He Experiment

I wrote about this experiment and discussed it with funding agencies long ago and just wanted to post the idea.

I am exploring the possibility of conducting high-Reynolds number turbulence experiments. One experiment would involve constructing a large isolated vessel filled with liquid helium to create fully developed, spatially localized high-Re flow through transient forcing mechanisms. The forcing would be induced either by localized heating using multiple femtosecond lasers or by mechanical grid motion. The experiment will focus on capturing the acoustic radiation produced by turbulence, which is deterministically linked to the flow-field. A total of 2500 microphones would be strategically embedded within the containment vessel’s walls to measure the acoustic signatures without disturbing the flow as intrusive methods contaminate the data. Additionally, sapphire windows will be integrated into the vessel to enable high-speed CCD cameras to track tracer particles introduced into the flow. These particles will be activated by a 5-kHz femtosecond laser system, capturing the temporal and spatial resolution.

The collected data will be used to reconstruct the turbulent field variables as a function of space and time. This reconstruction will be based on the theory of isotropic homogeneous turbulence and radiation, a framework I previously published. The method provides the foundation for predicting noise generated by homogeneous isotropic turbulence and is directly applicable to the proposed experiment. By combining predicted statistical models with time-dependent data and advanced beamforming techniques—specifically, those contained within the Acoular open-source code—the aim is to achieve a three-dimensional, time-dependent reconstruction of the turbulent field.

The primary focus will be on analyzing the intermittency and bursting phenomena that are characteristic of high-Re turbulence. These events generate strong acoustic impulses, which will be captured at a frequency of 180 kHz by the microphone array. The goal is to process this data to find the mechanisms behind these bursts and to create a high-fidelity database that could potentially be used to validate direct numerical simulations (DNS) in the future.

The experiment’s design addresses the limitations of previous liquid helium experiments, such as those conducted at Florida State and Minnesota, where intrusive measurement techniques altered the flow-field. By using acoustic measurements as a non-intrusive method, the experiment will capture the unique “fingerprint” of turbulence without affecting the flow itself. Each turbulent field radiates its own unique acoustic signature.

The expected outcomes include:

  • A comprehensive database of a high-Re number turbulent field with documented intermittent bursts and associated scaling.
  • New insights into the universal nature of small-scale turbulence within a high-Re field.
  • A better understanding of the hierarchical structure and nature of turbulence.

I think that such an experiment would take five years to conduct.

Research Notes on Konstantin Tsiolkovsky

“The Earth is the cradle of humanity, but one cannot live in the cradle forever.” – Konstantin Tsiolkovsky

In 1903, Tsiolkovsky wrote an article called, “Exploration of outer space by means of rocket devices,” in The Science Review.

Born in September 1857 in the village of Izhevskoye, Russia, Tsiolkovsky was the fifth child in a family of Polish descent. A bout of scarlet fever at the age of ten left him with significant hearing loss, limiting his formal education. Undeterred, he became an autodidact, immersing himself in physics and mathematics. The imaginative works of Jules Verne, especially “From the Earth to the Moon”, ignited his fascination with space travel. In 1876, Tsiolkovsky began his career as a schoolteacher in Borovsk, where he started crafting aeronautical experiments. In 1882, he moved to the town of Kaluga, dedicating his life to teaching and scientific inquiry. Working in virtual obscurity and without institutional support, he went into creating theory of space flight.

1883, Tsiolkovsky came up with an idea for reactive propulsion with the principle that a vehicle could propel itself by expelling part of its mass at high speed in the opposite direction. This insight was revolutionary, laying groundwork for modern rocket science. He mathematically derived the fundamental equation of rocket motion, now known as the Tsiolkovsky Rocket Equation, is the final total mass (after propellant is expended). This equation describes how rockets achieve velocity change, factoring in the expulsion of mass (still taught today by some historically minded faculty).

In 1903, Tsiolkovsky published his seminal work, “Exploration of Outer Space by Means of Rocket Devices”, in the Russian magazine Science Review (Nauchnoye Obozreniye) (see ref). He proposed the use of liquid hydrogen and liquid oxygen as rocket propellants. He envisioned multi-stage rockets, space stations, airlocks for spacewalks, and colonization of the Solar System (though not the originator of these ideas). Despite his new theories, Tsiolkovsky did not have resources to create experimental research or practical applications. His thoughts were unrecognized and remained in a small circle within Russia.

In 1919, his contributions were formally acknowledged when he was elected to the Socialist Academy, the precursor to the USSR Academy of Sciences. He was granted a government pension, allowing him to focus on research. His research inspired a new generation of engineers and scientists, including Sergei Korolev, the chief designer of Soviet space program (who was not known outside the Soviet Union for a long time and there are wonderful documentaries online about Korolev).

Suggest reading the biography by Kosmodemyansky, A. (2000), “Konstantin Tsiolkovsky: His life and work,” 2000.

References

  • Tsiolkovsky, K. S. (1903). Exploration of outer space by means of rocket devices. The Science Review, 5. (primary ref).
  • https://www.nasa.gov/history/sputnik/
  • Siddiqi, A. A. (2000). Challenge to Apollo: the Soviet Union and the space race, 1945-1974 (Vol. 4408). National Aeronautics and Space Administration, NASA History Division, Office of Policy and Plans.
  • Kosmodemyansky, A. (2000). Konstantin Tsiolkovsky: His life and work. The Minerva Group.

Early Rockets and Review Notes

One of the earliest documented uses of rockets was in China. Father Antoine Gaubil, a French Jesuit missionary and historian, described an event in his 1739 writings, “When it was lit, it made a noise that resembled thunder and extended 24 km. The place where it fell was burned, and the fire extended more than 2000 feet. These iron nozzles, the flying powder halberds that were hurled, were what the Mongols feared most.” This account details how, in 1232, the Chinese successfully defended the city of Kaifeng against a massive Mongol invasion using rocket-propelled fire arrows.

The Chinese are credited with the invention of black powder, a mixture of charcoal, sulfur, and saltpeter (potassium nitrate), in 9th century during the Tang dynasty. Initially used for medicinal purposes and fireworks, black powder’s potential as a propellant was realized. By the Song dynasty, the Chinese developed rudimentary rockets by attaching bamboo tubes filled with black powder to arrows, creating the so-called “fire arrows.” These fire arrows were psychological weapons and had destructive capabilities. During the Mongol invasions, the Chinese employed a variety of gunpowder weapons, including rockets, bombs, and flamethrowers, to defend their territories. These early rockets started to include aerodynamic design features to increase range.

Gunpowder and rocketry gradually spread westward through the Silk Road and during Mongol invasions. By the 13th and 14th centuries, the use of gunpowder weapons had reached the Middle East and Europe. The adaptation and advancement of these technologies in Europe were slow due to limited understanding and secrecy surrounding its composition. It was not until the 16th century that rocketry saw more systematic development in Europe, primarily for fireworks and signaling rather than as weapons. For example, the beginning of using gas lamps in Paris by the court was marked by fireworks, creating the saying ‘city of light.’

Sir William Congreve of England was inspired by the rockets used by the Kingdom of Mysore in India against British forces. Sir William sought to develop his own versions for the British military. Congreve designed rockets with improved propulsion and stability, using iron casings and sticks to help guide the rocket on its flight-path. His rockets were utilized during the Napoleonic Wars and notably in the War of 1812. The ‘rocket’s red glare'”‘ referenced by Francis Scott Key in The Star-Spangled Banner alludes to the Sir William’s rockets fired by British ships during the bombardment of Fort McHenry in 1814.

Rockets remained largely empirical devices until the late 19th and early 20th centuries when scientific principles were systematically applied by early aerospace engineers such as Konstantin Tsiolkovsky (Russian), Robert H. Goddard (American), and Hermann Oberth (German).

References

  • Gaubil, A. (1739). Histoire de Gentchiscan et de toute la Dinastie des Mongous ses successeurs conquérans de la chine: tirée de l’histoire chinoise. Chez Briasson, libraire… et Piget, libraire.
  • Needham, J. (1974). Science and civilisation in China (Vol. 5). Cambridge University Press.
  • Kelly, J. (2004). Gunpowder: alchemy, bombards, and pyrotechnics: the history of the explosive that changed the world. Basic Books (AZ).
  • Temple, R. (1986). The Genius of China: 3,000 Years of Science, Discovery, and Invention. Simon & Schuster.
  • Partington, J. R. (1999). A history of Greek fire and gunpowder. JHU Press.
  • Congreve, W. (1817). A Concise Account of the Origin and Progress of the Rocket System: With a View of the Apparent Advantages Both as to the Effect Produced, and Comparative Saving of Expense Arising from the Peculiar Facilities of Application which it Possesses, as Well for Naval as Military Purposes. A. O’Neil.
  • Tsiolkovsky, K. S. (1903). Exploration of outer space by means of rocket devices. The Science Review, 5.
  • Goddard, R. H. (1919). A Method of Reaching Extreme Altitudes, volume 71 (2) of Smithsonian Miscellaneous Collections. Smithsonian institution, City of Washington.
  • Oberth, H. (1984). Die Rakete zu den Planetenräumen. Oldenbourg Wissenschaftsverlag.

Hypersonics History of Reentry

Lately, I have been examining the entire history of hypersonics research and technology, with a particular focus on the re-entry problem and ablation for small vehicles, such as those from ballistic missiles. While reviewing the writings of Wernher von Braun, I was amused to find that he joked about using frozen balsa wood as a potential material for re-entry vehicles. The re-entry challenge was initially posed to the scientific community by Theodore von Kármán of CalTech GALCIT and JPL as one of the most formidable problems to solve.

Early aerodynamic designs, borrowed from supersonic studies, often featured pointed shapes; however, these were soon discounted by experimental results at NASA and associated analysis. Test rocket programs, which explored ballistic trajectories at varying speeds and altitudes, revealed that aerodynamic ‘heating ‘heat barrier’ was the primary problem – unlike in supersonics, where the sound barrier was the main concern.

Ultimately, materials such as glass substrates and nylon were the first to be successfully used as ablative materials. This is quite different from today’s approaches, which involve advanced materials, composites, and sophisticated analyses for active cooling or modern ablative materials.

Words and Virginia Woolf

Finally, and most emphatically, words, like ourselves, in order to live at their ease, need privacy. Undoubtedly they like us to think, and they like us to feel, before we use them; but they also like us to pause; to become unconscious. Our unconsciousness is their privacy; our darkness is their light… That pause was made, that veil of darkness was dropped, to tempt words to come together in one of those swift marriages which are perfect images and create everlasting beauty. But no – nothing of that sort is going to happen tonight. The little wretches are out of temper; disobliging; disobedient; dumb. What is it that they are muttering? “Time’s up! Silence!”

Virginia Woolf, BBC, April, 29, 1937

Kelly Johnson on X-Plane Programs

Our present research airplanes have developed startling performance only by the use of rocket engines and flying essentially in a vacuum. Testing airplanes designed for transonic flight speeds at Mach numbers between 2 and 3 has proven, mainly, the bravery of the test pilots and the fact that where there is no drag, the rocket engine can propel even mediocre aerodynamic forms at high Mach numbers.

I am not aware of any aerodynamic or power plant improvements to airbreathing engines that have resulted from our very expensive research airplane program. Our modern tactical airplanes have been designed almost entirely on NACA and other wind-tunnel data, plus certain rocket model tests…. — Kelly Johnson

Navier-Stokes Equations and Practicality

Because an effort is likely impossible and impractical does not mean it is not worth attempting. The Navier-Stokes equations and turbulent flow represent the last great classical problem in physics. Since the time of Leonard Euler and Jean-Baptiste le Rond d’Alembert, many have devoted much of their lives to working on these problems. Although they have all failed, they may have made incremental progress toward understanding the physics and mathematics of these significant partial differential equations.

Eight Years at Florida

It has now been eight years since I joined the University of Florida. Years ago, the University was a very different place. Many things have changed due to external and internal factors. One thing is for certain: I am told that the academic community and academics are always changing. To be a successful professor, much like in biological theory, one must be adaptable.

Deming and Statistics

In God we trust. All others must bring data. — W. Edwards Deming

Deming revolutionized quality management with his emphasis on data-driven decision-making. His 1950s lectures on Statistical Product Quality Administration in Japan were instrumental in Japan’s post-war economic growth, helping it become the world’s second-largest economy. Deming was awarded the National Medal of Technology in 1987 by President Ronald Reagan. The Deming Prize, created by the Japanese Union of Scientists and Engineers, honors contributions to Total Quality Management.