Walter Hohmann (; ; 18 March 1880 – 11 March 1945) was a German engineer who made an important contribution to the understanding of
orbital dynamics
Orbital mechanics or astrodynamics is the application of ballistics and celestial mechanics to the practical problems concerning the motion of rockets and other spacecraft. The motion of these objects is usually calculated from Newton's laws of ...
. In a book published in 1925, Hohmann demonstrated a fuel-efficient path to move a spacecraft between two different orbits, now called a
Hohmann transfer orbit
In astronautics, the Hohmann transfer orbit () is an orbital maneuver used to transfer a spacecraft between two orbits of different altitudes around a central body. Examples would be used for travel between low Earth orbit and the Moon, or ...
. He received his Ph.D. from the
RWTH Aachen University in 1920.
Biography
Hohmann was born in
Hardheim
Hardheim is a municipality in the district of Neckar-Odenwald-Kreis, in Baden-Württemberg, Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in E ...
, the son of a doctor. As a boy, he lived with his family in
Port Elizabeth,
South Africa
South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded to the south by of coastline that stretch along the Atlantic Ocean, South Atlantic and Indian Oceans; to the ...
for a time, before returning to Germany. He studied civil engineering at the Technical University of
Munich
Munich ( ; german: München ; bar, Minga ) is the capital and most populous city of the German state of Bavaria. With a population of 1,558,395 inhabitants as of 31 July 2020, it is the third-largest city in Germany, after Berlin and Ha ...
, graduating in 1904. He then worked for the municipal councils of
Vienna
en, Viennese
, iso_code = AT-9
, registration_plate = W
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, timezone = CET
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, timezone_DST ...
,
Hanover
Hanover (; german: Hannover ; nds, Hannober) is the capital and largest city of the German state of Lower Saxony. Its 535,932 (2021) inhabitants make it the 13th-largest city in Germany as well as the fourth-largest city in Northern Germany ...
and Breslau (now
Wrocław
Wrocław (; german: Breslau, or . ; Silesian German: ''Brassel'') is a city in southwestern Poland and the largest city in the historical region of Silesia. It lies on the banks of the River Oder in the Silesian Lowlands of Central Europe, rou ...
) before settling in
Essen, where he eventually held the post of chief architect.
Hohmann became interested in space as a young boy when his father would show him the southern constellations. As soon as he read the science fiction works of French author
Jules Verne and German author
Kurd Lasswitz
Kurd Lasswitz (german: link=no, Kurd Laßwitz; 20 April 1848 – 17 October 1910) was a German author, scientist, and philosopher. He has been called "the father of German science fiction". He sometimes used the pseudonym ''Velatus''.
Biograph ...
, he started to wonder, "How do you get up there?"
Between 1911 and 1912, while Hohmann was working as an engineer in Breslau, his older cousin sent him some astronomy textbooks. Hohmann soon began to fill up most of his free time with the study of astronomy, and started seriously considering the problem of interplanetary spaceflight.
Eventually, Hohmann realized that minimizing the amount of fuel that the spacecraft had to carry would be an important consideration, and he plotted a variety of orbits until he found the one that now bears his name. He published his findings in ''Die Erreichbarkeit der Himmelskörper (The Attainability of the Celestial Bodies)''.
[Walter Hohmann, ''Die Erreichbarkeit der Himmelskörper'' (''tr. "The Attainability of Heavenly Bodies"''; München, Germany: R. Oldenbourg, 1925).]
The importance of this work saw Hohmann become a leading figure in Germany's amateur rocketry movement in the late 1920s, the ''
Verein für Raumschiffahrt
''Verein'' is a German word, sometimes translated as ''union'', ''club'' or ''association'', and may refer to:
* '' Eingetragener Verein'' (e. V.), a registered voluntary association under German law
* Swiss Verein, a voluntary association under ...
'' (VfR — "Spaceflight Society"). Writer
Willy Ley
Willy or Willie is a masculine, male given name, often a diminutive form of William or Wilhelm, and occasionally a nickname. It may refer to:
People Given name or nickname
* Willie Aames (born 1960), American actor, television director, and scr ...
asked Hohmann to contribute to an anthology of papers on spaceflight, "Die Möglichkeit der Weltraumfahrt" (The Possibility of Space Travel), published in 1928. Hohmann contributed a post about "Fahrtrouten, Fahrzeiten und Landungsmöglichkeiten" (Routes, Timetables, and Landing Options) where he proposed using a separable landing module to travel to the Moon,
an idea that was later utilized in the Apollo lunar missions.
Following the rise to power of the
Nazi
Nazism ( ; german: Nazismus), the common name in English for National Socialism (german: Nationalsozialismus, ), is the far-right totalitarian political ideology and practices associated with Adolf Hitler and the Nazi Party (NSDAP) in ...
party, Hohmann distanced himself as much as possible from rocketry, wishing to play no part in the development of the rocket as a weapon. He died in an Essen hospital shortly before the end of
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...
as a result of stress experienced during the intense Allied bombing of the city.
Walter-Hohmann-Observatory
![walter hohmann sternwarte gedenktafel 2010](https://upload.wikimedia.org/wikipedia/commons/e/e1/Walter_hohmann_sternwarte_gedenktafel_2010.jpg)
In 2009 the Walter-Hohmann-Observatory in Essen, Germany installed a Commemorative plaque at their ground:
Walter Hohmann was born as the son of a doctor and visited the high-school in Würzburg (Germany), where he graduated In 1900. He studied engineering at the technical university in Munich (Germany) and worked from 1904 as an engineer for structural analysis in Vienna (Austria), Berlin (Germany), Hanover (Germany) and Wroclaw (Germany). From 1912 he worked as a city planner and director of the static building office and the department of materials testing of the city of Essen (Germany). Here he died in a hospital on 11.03.1945, shortly before the war ended. His honorary grave is located at the cemetery at "Meisenburgstraße" in the city of Essen (Germany).
In his spare time he devoted himself to celestial mechanics calculations, and in 1920 he published his book "Die Erreichbarkeit der Himmelskörper" (The Attainability of the Celestial Bodies). He developed basic principles and created advanced tools necessary for the conquest of space. His ideas were taken up for the Apollo program and the Voyager spacecraft (for example). Today he is considered a pioneer of space travel.
In recognition of his scientific achievements, a lunar crater was named after him in 1970. The Astronomical Association of Essen (Germany) gave itself the name "Walter-Hohmann-Observatory" in 1971. Also
asteroid 9661 Hohmann is named after him.
References
* Hohmann, Walter
''The Attainability of Heavenly Bodies''(Washington: NASA Technical Translation F-44, 1960).
* McLaughlin, William I. (2000)
"Walter Hohmann’s Roads In Space" ''Journal of Space Mission Architecture'' Issue 2: pp. 1–14.
External links
Homepage of the Walter-Hohmann-Observatory (German – Contact in English possible)
{{DEFAULTSORT:Hohmann, Walter
1880 births
1945 deaths
German aerospace engineers
German civil engineers
German spaceflight pioneers
19th-century German architects
RWTH Aachen University alumni
Technical University of Munich alumni
People from Neckar-Odenwald-Kreis
Engineers from North Rhine-Westphalia
20th-century German architects