Krafft Arnold Ehricke (March 24, 1917 – December 11, 1984) was a German

rocket A rocket (from , and so named for its shape) is a vehicle that uses jet propulsion to accelerate without using any surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely ...

-propulsion engineer and advocate for

space colonization Space colonization (or extraterrestrial colonization) is the human settlement, settlement or colonization of outer space and astronomical bodies. The concept in its broad sense has been applied to any permanent human presence in space, such ...

. Ehricke is a co-designer of the first

Centaur A centaur ( ; ; ), occasionally hippocentaur, also called Ixionidae (), is a creature from Greek mythology with the upper body of a human and the lower body and legs of a horse that was said to live in the mountains of Thessaly. In one version o ...

liquid oxygen/liquid hydrogen upper stage.

Biography

Born in

Berlin Berlin ( ; ) is the Capital of Germany, capital and largest city of Germany, by both area and List of cities in Germany by population, population. With 3.7 million inhabitants, it has the List of cities in the European Union by population withi ...

, Ehricke believed in the feasibility of space travel from a very young age, influenced by his viewing of the 1929

Fritz Lang Friedrich Christian Anton Lang (; December 5, 1890 – August 2, 1976), better known as Fritz Lang (), was an Austrian-born film director, screenwriter, and producer who worked in Germany and later the United States.Obituary ''Variety Obituari ...

film ''

Woman in the Moon ''Woman in the Moon'' (German language, German ''Frau im Mond'') is a German science fiction silent film that premiered 15 October 1929 at the UFA-Palast am Zoo cinema in Berlin to an audience of 2,000. It is often considered to be one of the f ...

''. At the age of 12, he formed his own rocket society. He attended the

Technische Hochschule A ''Technische Hochschule'' (, plural: ''Technische Hochschulen'', abbreviated ''TH'') is a type of university focusing on engineering sciences in Germany. Previously, it also existed in Austria, Switzerland, the Netherlands (), and Finland (, ) ...

in Berlin (today

Technische Universität Berlin (TU Berlin; also known as Berlin Institute of Technology and Technical University of Berlin, although officially the name should not be translated) is a public university, public research university located in Berlin, Germany. It was the first ...

) and studied

celestial mechanics Celestial mechanics is the branch of astronomy that deals with the motions of objects in outer space. Historically, celestial mechanics applies principles of physics (classical mechanics) to astronomical objects, such as stars and planets, to ...

and nuclear

physics Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge whi ...

under physicists including

Hans Geiger Johannes Wilhelm Geiger ( , ; ; 30 September 1882 – 24 September 1945) was a German nuclear physicist. He is known as the inventor of the Geiger counter, a device used to detect ionizing radiation, and for carrying out the Rutherford scatt ...

and

Werner Heisenberg Werner Karl Heisenberg (; ; 5 December 1901 – 1 February 1976) was a German theoretical physicist, one of the main pioneers of the theory of quantum mechanics and a principal scientist in the German nuclear program during World War II. He pub ...

, attaining his degree in

Aeronautical Engineering Aerospace engineering is the primary field of engineering concerned with the development of aircraft and spacecraft. It has two major and overlapping branches: aeronautical engineering and astronautical engineering. Avionics engineering is s ...

. He worked at

Peenemünde Peenemünde (, ) is a municipality on the Baltic Sea island of Usedom in the Vorpommern-Greifswald district in Mecklenburg-Vorpommern in north-eastern Germany. It is part of the ''Amt (country subdivision), Amt'' (collective municipality) of Used ...

as a propulsion engineer from 1942 to 1945 with Walter Thiel, then went to the United States with other German rocket scientists and technicians under "

Operation Paperclip The Operation Paperclip was a secret United States intelligence program in which more than 1,600 German scientists, engineers, and technicians were taken from former Nazi Germany to the US for government employment after the end of World War I ...

" in 1947. He worked for a short time with the Von Braun Rocket Team at Huntsville. In 1948, while working for the U.S. Army, Ehricke wrote a story about a crewed mission to Mars called "Expedition Ares". It anticipated the many challenges that still face explorers who will make the journey in the future. In the same year he wrote a book with Wernher von Braun, '' The Mars Project'', which detailed how man could travel to

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

using a ferry system. Upon leaving government service in 1952, Ehricke worked at

Bell Aircraft The Bell Aircraft Corporation was an American aircraft manufacturer, a builder of several types of fighter aircraft for World War II but most famous for the Bell X-1, the first supersonic aircraft, and for the development and production of many i ...

, and then moved to Convair in 1954. While at Convair, he designed the D-1 Centaur, the world's first upper-stage-booster that used liquid hydrogen and oxygen. He also created an early space station design, based on launch by Convair's Atlas rocket. The NEXUS reusable rocket was a 1960s concept designed by a group at

General Dynamics General Dynamics Corporation (GD) is an American publicly traded aerospace and defense corporation headquartered in Reston, Virginia. As of 2020, it was the fifth largest defense contractor in the world by arms sales and fifth largest in the Unit ...

led by Ehricke. Also, during his stay at General Dynamics, he participated in

Project Orion (nuclear propulsion) Project Orion was a study conducted in the 1950s and 1960s by the United States Air Force, DARPA, and NASA into the viability of a nuclear pulse spaceship that would be directly propelled by a series of atomic explosions behind the craft. F ...

Model Space Station with Kraft Ehricke at Blackboard

In 1966, Ehricke was inducted into the International Aerospace Hall of Fame for his engineering achievements and his influential ideas on the purpose of space exploration. Ehricke undertook a major, multi-decade study of the industrial development of the Moon, which he described as Earth's "seventh continent." His lunar industrialization concept was based on the most advanced technologies, such as nuclear-powered freight transporters, and using fusion energy to power his city, Selenopolis, on the Moon. Ehricke famously stated in 1984, "If God wanted man to become a spacefaring species, He would have given man a Moon." He married Ingeborg Ehricke (born 12 September 1922). Ehricke received a space burial on April 21, 1997, when a rocket sent a small amount of his cremated remains into Earth orbit.

Contributions to space flight dynamics

Ehricke was well-known in the field of

astrodynamics Orbital mechanics or astrodynamics is the application of ballistics and celestial mechanics to rockets, satellites, and other spacecraft. The motion of these objects is usually calculated from Newton's laws of motion and the Newton's law of univ ...

and its applications; he published two-volume textbook ''Space Flight'' in 1959. It focuses on methods for exploration of the

Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Sola ...

. Although he was not the first, he clearly demonstrated the so-called "

gravity assist A gravity assist, gravity assist maneuver, swing-by, or generally a gravitational slingshot in orbital mechanics, is a type of spaceflight flyby (spaceflight), flyby which makes use of the relative movement (e.g. orbit around the Sun) and gra ...

" method for utilizing hyperbolic encounters with an intermediate planet to increase (or decrease) the velocity and orbital elements of a space vehicle. This technique was essential for the exploration of the Solar System. Examples include the Voyager missions to the outer planets and the recent ''

New Horizons ''New Horizons'' is an Interplanetary spaceflight, interplanetary space probe launched as a part of NASA's New Frontiers program. Engineered by the Johns Hopkins University Applied Physics Laboratory (APL) and the Southwest Research Institut ...

'' mission to

Pluto Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of Trans-Neptunian object, bodies beyond the orbit of Neptune. It is the ninth-largest and tenth-most-massive known object to directly orbit the Su ...

. His contribution to this important field of exploration has been neglected for many decades and incorrect claims of the "invention" of gravity assist were made by

Michael Minovitch Michael Andrew Minovitch ( 1936 - 16 September 2022) was an American mathematician who developed gravity assist technique when he was a UCLA graduate student and working summers at NASA's Jet Propulsion Laboratory The Jet Propulsion Laborat ...

Extraterrestrial Imperative

Ehricke promoted a

philosophical Philosophy ('love of wisdom' in Ancient Greek) is a systematic study of general and fundamental questions concerning topics like existence, reason, knowledge, Value (ethics and social sciences), value, mind, and language. It is a rational an ...

concept called the "Extraterrestrial Imperative." This idea refers to Ehricke's belief that it was the responsibility of humanity to explore space and exploit the resources of the

, in order to sustain the development of the species. There are no external "limits to growth," Ehricke insisted, because while the Earth is a "closed system," the exploration of space opens the universe to humanity. For Ehricke, human creativity has no limits.

References

External links

www.hq.nasa.gov

Ehricke, Krafft

Astrophysics Data System The SAO/NASA Astrophysics Data System (ADS) is a digital library portal for researchers on astronomy and physics, operated for NASA by the Smithsonian Astrophysical Observatory. ADS maintains three bibliographic collections containing over 15 ...

Krafft Arnold Ehricke
(in German) from the archive of the Österreichische Mediathek {{DEFAULTSORT:Ehricke, Krafft Arnold 1917 births 1984 deaths 20th-century German inventors V-weapons people German aerospace engineers German spaceflight pioneers NASA people Engineers from Berlin People from Huntsville, Alabama German rocket scientists Space advocates American technology writers German technology writers Technische Universität Berlin alumni Space burials Deaths from leukemia in California Operation Paperclip German male non-fiction writers 20th-century American essayists 20th-century American male writers American male non-fiction writers

Biography

Contributions to space flight dynamics

Extraterrestrial Imperative

Further reading

References

External links