Question: Oberth effect is named after a physicist who passed away in what year ?

full_context: Document 1: Ulrich Walter: Prof. Dr. Ulrich Hans Walter (born February 9, 1954) is a German physicist/engineer and a former DFVLR astronaut.
Document 2: Oberth effect: In astronautics, a powered flyby, or Oberth maneuver, is a maneuver in which a spacecraft falls into a gravitational well, and then accelerates when its fall reaches maximum speed. The resulting maneuver is a more efficient way to gain kinetic energy than applying the same impulse outside of a gravitational well. The gain in efficiency is explained by the Oberth effect, wherein the use of an engine at higher speeds generates greater mechanical energy than use at lower speeds. In practical terms, this means that the most energy-efficient method for a spacecraft to burn its engine is at the lowest possible orbital periapse, when its orbital velocity (and so, its kinetic energy) is greatest. In some cases, it is even worth spending fuel on slowing the spacecraft into a gravity well to take advantage of the efficiencies of the Oberth effect. The maneuver and effect are named after Hermann Oberth, the Austro-Hungarian-born German physicist and a founder of modern rocketry, who first described them in 1927.
Document 3: Johannes Kepler ATV: The "Johannes Kepler" ATV, or Automated Transfer Vehicle 002 (ATV-002), was an unmanned cargo spacecraft built to resupply the International Space Station (ISS). It was launched on 16 February 2011 by the European Space Agency (ESA). "Johannes Kepler" carried propellant, air and dry cargo weighing over 7000 kg , and had a total mass of over 20000 kg , making it, at the time, the heaviest payload launched by the ESA. The spacecraft was named after the 17th-century German astronomer Johannes Kepler.
Document 4: Orion abort modes: NASA's newest spacecraft, the Orion Multi-Purpose Crew Vehicle (MPCV), will be the first American spacecraft since Project Apollo to use an escape system in the event of a launch abort, something its predecessor, the Space Shuttle, had for only its first four orbital test flights in 1981-1982. Like the Apollo Command-Service Module (CSM), the Orion CEV will use the Launch escape system (LES), a solid-fueled tractor rocket that will be able to pull the Orion crew module away from a malfunctioning Space Launch System (SLS) rocket during the initial launch phase. Based on the launch escape system found on the Soviet/Russian Soyuz spacecraft, the LAS, designed and manufactured by ATK for the Orion CEV, will be larger than the Soyuz version and will have more thrust than the Atlas 109-D booster that carried astronaut John Glenn into orbit in 1962.
Document 5: Walter Dornberger: Major-General Dr. Walter Robert Dornberger (6 September 1895 – 27 June 1980) was a German Army artillery officer whose career spanned World War I and World War II. He was a leader of Nazi Germany's V-2 rocket program and other projects at the Peenemünde Army Research Center.
Document 6: Christian Doppler: Christian Andreas Doppler ( ; ] ; 29 November 1803 – 17 March 1853) was an Austrian mathematician and physicist. He is celebrated for his principle — known as the Doppler effect — that the observed frequency of a wave depends on the relative speed of the source and the observer. He used this concept to explain the color of binary stars.
Document 7: Ramjet: A ramjet, sometimes referred to as a flying stovepipe or an athodyd (an abbreviation of aero thermodynamic duct), is a form of airbreathing jet engine that uses the engine's forward motion to compress incoming air without an axial compressor. Because ramjets cannot produce thrust at zero airspeed, they cannot move an aircraft from a standstill. A ramjet-powered vehicle, therefore, requires an assisted take-off like a rocket assist to accelerate it to a speed where it begins to produce thrust. Ramjets work most efficiently at supersonic speeds around 3 Mach . This type of engine can operate up to speeds of 6 Mach .
Document 8: Space fountain: A space fountain is a proposed form of structure extending into space that, like a space elevator, can extend to geostationary orbit, but does not rely on tensile strength for support. In contrast to the space elevator design, a space fountain is a tremendously tall tower extending up from the ground. Since such a tall tower could not support its own weight using traditional materials, fast-moving pellets are projected upward from the bottom of the tower and redirected back down once they reach the top, so that the force of redirection holds the top of the tower aloft. Payloads ascend or descend by coupling with this stream of pellets or by climbing up the side of the tower. The space fountain has some advantages over a space elevator in that it does not require materials with extreme strength, can be located at any point on a planet's surface instead of just the equator, and can be raised to heights lower than the level of geostationary orbit. Its major disadvantages come about from the fact that it is an extremely-high-energy active structure. It requires constant power input to make up energy losses and remain erect. The high energy content of the kinetic component of the structure also continually threatens to cause the collapse of the tower if the containment systems fail.
Document 9: Pontryagin's maximum principle: Pontryagin's maximum (or minimum) principle is used in optimal control theory to find the best possible control for taking a dynamical system from one state to another, especially in the presence of constraints for the state or input controls. It was formulated in 1956 by the Russian mathematician Lev Pontryagin and his students. It has as a special case the Euler–Lagrange equation of the calculus of variations.
Document 10: Arthur Rudolph: Arthur Louis Hugo Rudolph (November 9, 1906 – January 1, 1996) was a German Nazi rocket engineer who was a leader of the effort to develop the V-2 rocket for Nazi Germany. After the war, the United States Government's Office of Strategic Services (OSS) brought him to the U.S. as part of the clandestine Operation Paperclip, where he became one of the main developers of the U.S. space program. He worked within the U.S. Army and NASA, where he managed the development of several systems, including the Pershing missile and the Saturn V Moon rocket. In 1984, the U.S. Government investigated him for war crimes, and he agreed to renounce his United States citizenship and leave the U.S. in return for not being prosecuted.
Document 11: Herman Bank: Herman Bank (October 26, 1916 - November 2, 2012) was an American mechanical engineer who worked for the Jet Propulsion Laboratory (JPL) from 1947 to 1984. He was one of the “Rocket Boys” who were first generation scientist and engineers of the Space Age.
Document 12: Gerhard Thiele: Dr. Gerhard Paul Julius Thiele (born September 2, 1953) is a German physicist and a former ESA astronaut.
Document 13: Penrose process: The Penrose process (also called Penrose mechanism) is a process theorised by Roger Penrose wherein energy can be extracted from a rotating black hole. That extraction is made possible because the rotational energy of the black hole is located not inside the event horizon of the black hole, but on the outside of it in a region of the Kerr spacetime called the ergosphere, a region in which a particle is necessarily propelled in locomotive concurrence with the rotating spacetime. All objects in the ergosphere become dragged by a rotating spacetime. In the process, a lump of matter enters into the ergosphere of the black hole, and once it enters the ergosphere, it is forcibly split into two parts. For example, the matter might be made of two parts that separate by firing an explosive or rocket which pushes its halves apart. The momentum of the two pieces of matter when they separate can be arranged so that one piece escapes from the black hole (it "escapes to infinity"), whilst the other falls past the event horizon into the black hole. With careful arrangement, the escaping piece of matter can be made to have greater mass-energy than the original piece of matter, and the infalling piece has negative mass-energy. Although momentum is conserved the effect is that more energy can be extracted than was originally provided, the difference being provided by the black hole itself. In summary, the process results in a slight decrease in the angular momentum of the black hole, which corresponds to a transference of energy to the matter. The momentum lost is converted to energy extracted.
Document 14: Hermann Oberth: Hermann Julius Oberth (] ; 25 June 1894 – 28 December 1989) was an Austro-Hungarian-born German physicist and engineer. He is considered one of the founding fathers of rocketry and astronautics, along with the French Robert Esnault-Pelterie, the Russian Konstantin Tsiolkovsky and the American Robert Goddard.
Document 15: Wubbo Ockels: Wubbo Johannes Ockels (28 March 1946 – 18 May 2014) was a Dutch physicist and an astronaut of the European Space Agency (ESA). In 1985 he participated in a flight on the space shuttle Challenger, STS-61-A, making him the first Dutch citizen in space. After his astronaut career, Ockels was professor of "Aerospace for Sustainable Engineering and Technology" at the Delft University of Technology.
ground_truth: 1989