However, it is more fuel-efficient for a craft to burn its fuel as close to the ground as possible ; see Oberth effect and reference.

* The Oberth effect: doing burns deep in gravity fields to gain speed

* Oberth effect

Another effect is the Oberth effect-this can be used to greatly decrease the delta-v needed, as using propellant at low potential energy / high speed multiplies the effect of a burn.

Because the slingshot effect and Oberth effect depend on the position and motion of bodies, the delta-v budget changes with launch time.

In astronautics, the Oberth effect is where the use of a rocket engine when travelling at high speed generates much more useful energy than one at low speed.

Oberth effect occurs because the propellant has more usable energy ( due to its kinetic energy on top of its chemical potential energy ) and it turns out that the vehicle is able to employ this kinetic energy to generate more mechanical power.

It is named after Hermann Oberth, the Austro-Hungarian-born, German physicist and a founder of modern rocketry, who apparently first described the effect.

Oberth effect is used in a powered flyby or Oberth maneuver where the application of an impulse, typically from the use of a rocket engine, close to a gravitational body ( where the gravity potential is low, and the speed is high ) can give much more change in kinetic energy and final speed ( i. e. higher specific energy ) than the same impulse applied further from the body for the same initial orbit.

For the Oberth effect to be most effective, the vehicle must be able to generate as much impulse as possible at the lowest possible altitude ; thus the Oberth effect is often far less useful for low-thrust reaction engines such as ion drives, which have a low propellant flow rate.

Oberth effect also can be used to understand the behaviour of multi-stage rockets ; the upper stage can generate much more usable kinetic energy than might be expected from simply considering the chemical energy of the propellants it carries.

* Oberth effect

The technique to do this uses the Oberth effect, where releasing the payload when the tether is moving with higher linear speed, lower in a gravitational potential gives more specific energy, and ultimately more speed than the energy lost picking up the payload at a higher gravitational potential, even if the rotation rate is the same.

By his own account and that of many others, around the age of 11 years old, Oberth became fascinated with the field in which he was to make his mark through reading the writings of Jules Verne, especially From the Earth to the Moon and Around the Moon, re-reading them to the point of memorization.

" Oberth criticized the German system of education, saying " Our educational system is like an automobile which has strong rear lights, brightly illuminating the past.

In parts of 1928 and 1929, Oberth also worked in Berlin, Germany as a scientific consultant on the first film ever to have scenes set in outer space, Frau im Mond (" The Woman in the Moon "), which was directed and produced by the great film pioneer Fritz Lang at the Universum Film AG company.

In the autumn of 1929, Oberth conducted a static firing of his first liquid-fueled rocket motor, which he named the Kegeldüse.

Around the end of World War II in Europe in May 1945, the Oberth family moved to the town of Feucht, near Nuremberg, Germany, which became part of the American Zone of occupied Germany, and also the location of the high-level war-crimes trials of the surviving Nazi leaders.

In 1953, Oberth returned to Feucht, Germany, to publish his book Menschen im Weltraum ( Men in Space ), in which he described his ideas for space-based reflecting telescopes, space stations, electric-powered spaceships, and space suits.

* In the 1920s, Hermann Oberth described a method in which the rocket is assembled vertically on a floating barge, which he used in the movie Frau im Mond.

He also joined Germany's amateur rocket movement, the Verein für Raumschiffahrt ( VfR-" Society for Space Travel ") which was centered on Oberth.

The year before, Hermann Oberth had published the influential theoretical work " Die Rakete zu den Planetenräumen " (" The rocket to interplanetary space "), which in turn introduced Zander and other Russian enthusiasts to the ground breaking work by Robert Goddard (" A Method of Reaching Extreme Altitudes " published in 1919 ).

A major stimulus for the project was Friedwardt Winterberg's inertial confinement fusion drive concept for which he received the Hermann Oberth gold medal award.

Nearby craters of note include Tikhov, which is nearly attached to the southeast rim, Oberth to the west, and Schjellerup to the north-northwest.

The Hermann Oberth society is an association named after Hermann Oberth, the German astronautics pioneer, which develops and builds rockets and trains engineers in space technology.

At this time Berthold Seliger began to build rockets in this society, which was renamed the Hermann Oberth society.

In 1961 Berthold Seliger created his own company, the Seliger Forschungs-und Entwicklungsgesellschaft mbH, which cooperated with the Hermann Oberth society.

Exhibits include a Kumulus rocket and a Cirrus rocket, which were developed at the beginning of the 1960s by the Hermann Oberth Society and launched near Cuxhaven, Germany.

It features some books, models, awards and recognitions which belonged to Hermann Oberth.

Hermann Oberth worked on the design during 1941, and in December 1941 Walter Thiel proposed that the A10 use an engine composed of six bundled A4 engines, which it was thought would give a total thrust of 180 tonnes.

In 1892 Sir James Dewar invented a container that could keep liquids hot or cold ( the thermos ) which led three men – Tsiolkovsky, Robert Goddard, and Hermann Oberth – to construct a large thermal flask for either liquid hydrogen and oxygen or for solid fuel combustion for use in rocket propulsion, applying the thermal flask principle to keep rocket fuel cold and successfully using it for the V-2 rocket and the Saturn V rocket that put man on the moon.

High-pressure pumps for larger missiles had been discussed by rocket pioneers such as Hermann Oberth.

Starting in 1930, he attended the Technical University of Berlin, where he assisted Oberth in liquid-fueled rocket motor tests.

Influenced by Verne's books and ideas, Oberth constructed his first model rocket as a school student at the age of 14.

) Oberth moved to Peenemünde, Germany, in 1941 to work on Nazi German rocketry projects, including the V-2 rocket weapon, and in about September 1943, he was awarded the Kriegsverdienstkreuz I Klasse mit Schwertern ( War Merit Cross 1st Class, with Swords ) for his " outstanding, courageous behavior ... during the attack " on Peenemünde by Operation Hydra, part of Operation Crossbow.

In 1960, back in the United States again, Oberth went to work for the Convair Corporation as a technical consultant on the Atlas rocket program.

In July 1969, Oberth returned to the United States to witness the launch of the Apollo project Saturn V rocket from the Kennedy Space Center in Florida that carried the Apollo 11 crew on the first landing mission to the Moon.

Ley and Oberth had hoped to receive funding from Lang for a real life experimental rocket launch coinciding with the movie's premier.

He also began corresponding with every known rocket enthusiast in Europe, including Oberth himself.

Oberth was tasked with building a small rocket, to be launched at the film's premiere.

Since rocket scientist Hermann Oberth worked as an advisor on this movie ( he had originally intended to build a working rocket for use in the film ; time and technology kept this from happening ), it was popular among the rocket scientists in Wernher von Braun's circle at the Verein für Raumschiffahrt ( VfR ).

Karl Poggensee and the Hermann Oberth society ( succeeded by the DAFRA, German work company for affairs of rocket ) operated between 1952 and 1957 a launch site for small rockets with a maximum flight level of some kilometers, close to this farm.

A Kumulus rocket is on display at the Hermann Oberth Space Travel Museum in Feucht.

After the termination of rocket launches in the Cuxhaven area the Hermann Oberth society put its emphasis on the education of future space technology engineers.

The Cirrus is a sounding rocket with two stages, developed by the " Hermann Oberth Society ".

A Cirrus rocket is exhibited at the Hermann Oberth Space Travel Museum in Feucht, Germany.