Robert Albert Charles Esnault-Pelterie (French pronunciation: [ʁɔbɛʁ albɛʁ ʃaʁl eno pɛltəʁi]; 8 November 1881 – 6 December 1957) was a French aircraft designer and spaceflight expert. He is known as one of the early pioneers of modern rocketry and astronautics, along with Russian Konstantin Tsiolkovsky, Chinese Qian Xuesen, German Hermann Oberth, German Wernher von Braun, and American Robert H. Goddard.

Biography

He was born on November 8, 1881, in Paris to a man who owned a textile business. He studied at the Faculty of Sciences and pursued engineering at the Sorbonne.

He served in World War I and was awarded the title of Officier de la Légion d'Honneur.

In November 1928, while traveling on the ship Ile de France to New York City, he married Carmen Bernaldo de Quirós. She was the daughter of Don Antonio and Yvonne Cabarrus, and the granddaughter of General Marquis of Santiago, Grandee of Spain, and Head of the Military Household of Queen Isabella II.

He died on December 6, 1957, in Nice, France.

REP

Esnault-Pelterie designed and built airplanes and airplane engines under the name REP. His first attempts at flying were inspired by the Wright brothers’ 1902 glider. His first glider was tested on a beach near Calais but did not work well. He did not fully understand the Wright brothers’ glider, and although he used a similar method called wing-warping to control the plane, it failed and was stopped because he thought it was unsafe. After criticizing the Wright brothers’ method, he created a new control system using ailerons. These were small, movable parts on the wings. His use of ailerons is believed to be the first of its kind, even though a British inventor named M. P. W. Boulton had described a similar idea in a patent approved in 1868.

In 1906, he tested flying with a rope pulling the plane. On September 19, 1906, he flew 500 meters (1,600 feet). His first powered flight happened on October 10, 1907, covering 100 meters (330 feet) with the REP 1. This plane used a seven-cylinder, 30 horsepower engine he designed.

Trials of the REP 2 monoplane began on June 8, 1908. This plane set a record with a flight of 1,200 meters (3,900 feet), reaching an altitude of 30 meters (98 feet). After a modified version of this plane flew for the last time in 1909 at Rheims, Pelterie stopped flying and focused on building airplanes.

The Vickers R.E.P. Type Monoplane was based on his designs and marked the start of airplane production at Vickers Limited. In 1912, he introduced the REP Type N, and in 1914, the REP Parasol monoplane.

His family had invested a lot of money to help fund his airplane designs, which nearly caused them to go bankrupt. However, he invented the “joystick” flight control system and held a patent for it. This design was used in 1908 by French pilot Louis Blériot in his eighth airplane, setting a standard for future flight controls. After World War I, Esnault-Pelterie fought legal battles over his joystick patent. Many airplanes built during the war used his design, and the companies owed him money. The money he won and the royalties he received made him wealthy, allowing him to pay back his father’s investment.

Esnault-Pelterie designed and built his own airplane engines, which he sold under the name R.E.P. These engines had a unique design with multiple rows of cylinders arranged in a special way. The first model had seven cylinders, with four in one row and three in another, and produced 30 horsepower. A later model had 14 cylinders arranged in four rows and produced 60 horsepower.

Rocketry

He became interested in space travel and, unaware of Tsiolkovsky's 1903 research, created a paper in 1913 that introduced the rocket equation and calculated the energy needed to reach the Moon and nearby planets. In this paper, he suggested using atomic energy, specifically 400 kg of radium, to power a spaceship. His final work, L'Astronautique, was published in 1930. A later version released in 1934 included information about traveling between planets and using nuclear power.

On June 8, 1927, Esnault-Pelterie gave a presentation to the Société astronomique de France (French Astronomical Society) titled L'exploration par fusées de la très haute atmosphère et la possibilité des voyages interplanétaires, which discussed exploring outer space using rocket propulsion. Jean-Jacques Barré attended the lecture and began discussing rocketry with Esnault-Pelterie.

In 1929, Esnault-Pelterie suggested the idea of a ballistic missile for military use. By 1930, he and Barré had convinced the French War Department to fund a study of the concept. In 1931, the two tested different rocket propulsion systems, including liquid fuels. That same year, Esnault-Pelterie demonstrated a rocket engine powered by gasoline and liquid oxygen. During an experiment with a rocket design using tetra-nitromethane, he lost four fingers on his right hand in an explosion. Despite these efforts, their work did not generate interest in rocketry in France.

Prix REP-Hirsch

The Prix REP-Hirsch was an international award given by the Société astronomique de France to honor work in the study of space travel and astronautics. It was created by Esnault-Pelterie and André-Louis Hirsch, a Parisian banker who loved science. This prize was the first in the world for astronautics. The award was given "to recognize the best original scientific work, theoretical or experimental, that helps solve problems about space travel or improves understanding of astronautics." The idea for the prize began during a dinner in Paris on December 26, 1927. At the dinner, guests discussed the new science of space travel, which they called "astronautics" because of a suggestion by science fiction writer J.H. Rosny the elder. Hirsch and Esnault-Pelterie gave 5,000 francs each year from 1928 to 1930 to the Société astronomique de France to fund the prize. A group called the Comité d'Astronautique was formed to manage the award. Members of the committee included Esnault-Pelterie, Hirsch, Rosny the elder, General Gustave-Auguste Ferrié (President), Jean Perrin and Eugène Fichot (Vice-Presidents), and other experts. The prize was given for 10 years. In 1936, the name changed to the Prix International d'Astronautique (International Astronautics Prize). The winners were:

• 1929 — Hermann Oberth, for his work in the field of astronautics.
• 1931 — Pierre Montagne, for his theoretical work on how gas temperatures balance in combustion chambers.
• 1934 — Pierre Montagne, for his work on chemical reactions and their use in rockets, and Ary Sternfeld (Prix d'Encouragement), for his book Initiation à la Cosmonautique.
• 1935 — Louis Damblanc, for his improvements to solid rocket fuel.
• 1936 — American Rocket Society and Alfred Africano.
• 1938 — Giovanni Serragli, for his publication Recherches sur les poudres lentes et leur usage pour l'exploration de la haute atmosphère.
• 1939 — Frank J. Malina (Médaille de vermeil) and Nathan Carver (Médaille d'argent).

Although the award lasted only a short time, it helped increase interest in astronautics and supported early scientists in the field.

• 2019 — Jacques Blamont

Legacy

He enjoyed activities such as horseback riding, playing golf, camping, and driving cars. Throughout his life, he held patents for many inventions in areas like metalworking and car parts. He created the "center stick" control system for airplanes and designed a new kind of fuel pump. He also helped develop a method to control rockets using directed force.

Honors

• In 1930, he received the Prix Jules Janssen, the most important award given by the French astronomical society, the Société astronomique de France.
• He was a member of the French Academy.
• A crater on the Moon, called Esnault-Pelterie, is named after him.
• A street in Paris, known as rue Robert Esnault-Pelterie in the 7th arr., is named after him.
• He was added to the first group of people honored in the International Space Hall of Fame.

Works by Esnault-Pelterie

• L'Astronautique, Published in Paris by A. Lahure in 1930.
• L'Astronautique-Complément, Published in Paris by the Society of Civil Engineers of France in 1935.