Robert h. Goddard (1882-1945)

Robert Goddard began his experiments in rocketry while studying for his doctorate at Clark University in Worcester, Massachusetts. Goddard's doctoral dissertation "On the Conduction of Electricity at Contacts of Dissimilar Solids", 1911, was not related to rocketry, but was rather in the "main stream" physics. Goddard experimentally studied anisotropic changes in the electrical resistance of loosely powdered substances, particularly barium sulphide. The emerging radio technology relied on such materials for receiving the signals. Today we would call this area of research experimental solid-state physics.

His Ph.D. degree attained, Goddard actively embarked on research in rocketry, when he joined the faculty of Clark University in 1914. His basic research and development of new technology would achieve many rocket "firsts" and bring him 214 patents. He would often be called the Father of Modern Rocketry. Goddard concentrated first on the study of solid-propellant gunpowder rockets and improving their efficiency. The term "efficiency," introduced by him, meant "the ratio of the kinetic energy of the expelled gases to the heat energy of the powder."

Robert Goddard presented the results of his early rocket work in the Smithsonian Miscellaneous Collections, 1919, a publication of the respectable Smithsonian Institution. This famous treatise of Goddard, entitled "A Method of Reaching Extreme Altitudes," outlined his ideas on rocketry and included detailed calculations of rocket dynamics and results of his various tests.

In 1935 the first liquid-propellant rocket accelerated to a speed faster than the speed of sound. Two years later, on 26 March 1937, the Goddard's rocket reached an altitude 8000 — 9000 ft (2400 — 2700 m). All of this work was performed by Robert Goddard practically alone, with a few assistants. History would demonstrate, in a few years only, that the time of such individual effort has gone. The development of a modern powerful rocket would require a concerted effort of hundreds and thousands of scientists and engineers backed by the vast resources; the task possible only with the support of a mighty state.

Robert H. Goddard died on 10 August 1945, in Baltimore a few days after World War II ended. The recognition of Goddard's work came only long after his death. In 1959 the U.S. Congress honored Robert H. Goddard, and NASA named after him one of its leading field centers, Goddard Space Flight Center, in Greenbelt, Maryland, on May l.

Hermann Oberth (1894-1989)

Hermann Oberth was born on 25 June 1894, to a German family in Transylvania, a region of Austria — Hungary and now a part of Rumania. When he was 11 years old, Hermann had become fascinated by spaceflight afler reading Jules Verne's From the Earth to the Moon.

Oberth’s book appeared in 1923 under the title “The Rocket into Interplanetary Space”. In his book, Hermann Oberth focused on rocket dynamics. He considered the powered vertical flight through the atmosphere and introduced a concept of the optimal velocity that minimizes propellant consumption. He showed how a rocket could achieve the velocity allowing it to escape Earth's gravity. He described the details of liquid-propellant engines and calculated propellant exhaust velocities. Oberth introduced a number of ideas such as rocket staging, film cooling of the engine walls, and strengthening the structure by pressurizing propellant tanks.

The book presented a detailed design of a two-stage rocket with extensive supporting engineering calculations. The rocket used liquid oxygen as an oxidizer. The fuel was liquid hydrogen for the second -(upper) stage engine and the alcohol-water mixture for the first- (lower) stage engine. The latter combination would be used in the famous German A-4 (V-2) ballistic missile in 1940s.

Oberth joined the German Society for Space Travel and became its president in 1929.

Hermann Oberth played an important role in practical development of rocketry in Germany in the 1930s and provided inspiration for a generation of.