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Nuclear Pulse Propulsion
Nuclear pulse propulsion or external pulsed plasma propulsion is a hypothetical method of spacecraft propulsion that uses nuclear explosions for thrust. It originated as Project ''Orion'' with support from DARPA, after a suggestion by Stanislaw Ulam in 1947. Newer designs using inertial confinement fusion have been the baseline for most later designs, including Project ''Daedalus'' and Project ''Longshot''. History Los Alamos Calculations for a potential use of this technology were made at the laboratory from and toward the close of the 1940s to the mid 1950s. Project Orion Project Orion was the first serious attempt to design a nuclear pulse rocket. A design was formed at General Atomics during the late 1950s and early 1960s, with the idea of reacting small directional nuclear explosives utilizing a variant of the Teller–Ulam two-stage bomb design against a large steel pusher plate attached to the spacecraft with shock absorbers. Efficient directional explosives maximi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Partial Test Ban Treaty
The Partial Test Ban Treaty (PTBT) is the abbreviated name of the 1963 Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and Under Water, which prohibited all nuclear weapons testing, test detonations of nuclear weapons except for those conducted underground nuclear weapons testing, underground. It is also abbreviated as the Limited Test Ban Treaty (LTBT) and Nuclear Test Ban Treaty (NTBT), though the latter may also refer to the Comprehensive Nuclear-Test-Ban Treaty (CTBT), which succeeded the PTBT for ratifying parties. Negotiations initially focused on a comprehensive ban, but that was abandoned because of technical questions surrounding the detection of underground tests and Soviet concerns over the intrusiveness of proposed verification methods. The impetus for the test ban was provided by rising public anxiety over the magnitude of nuclear tests, particularly tests of new thermonuclear weapons (hydrogen bombs), and the resulting nuclear fallout. A test ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alan Bond (engineer)
Alan Bond (born 1944) is a British mechanical and aerospace engineer, who served as Managing Director of Reaction Engines Ltd and associated with Project Daedalus, Blue Streak missile, HOTOL, Reaction Engines Skylon and the Reaction Engines A2 hypersonic passenger aircraft. Career Alan Bond is an engineer, with a degree in Mechanical Engineering. He worked on liquid rocket engines, principally the RZ.2 (liquid oxygen / kerosene) and the RZ.20 (liquid oxygen / liquid hydrogen) at Rolls Royce under the tutelage of Val Cleaver, and he was also involved with flight trials of the Blue Streak at Woomera. He then worked for about 20 years at UK Atomic Energy Authority's Culham Laboratory on nuclear fusion, on the JET and RFX nuclear research projects. He was engaged in studies for the application of fusion to interplanetary space travel. He is the leading author of the report on the Project Daedalus interstellar, fusion powered starship concept, published by the British In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Interplanetary Society
The British Interplanetary Society (BIS), founded in Liverpool in 1933 by Philip E. Cleator, is the oldest existing space advocacy organisation in the world. Its aim is exclusively to support and promote astronautics and space exploration. Structure It is a non-profit organisation with headquarters in London and is financed by members' contributions. It is situated on South Lambeth Road ( A203) near Vauxhall station. History The BIS was only preceded in astronautics by the American Interplanetary Society (founded 1930), the German VfR (founded 1927), and Soviet Society for Studies of Interplanetary Travel (founded 1924), but unlike those it never became absorbed into a national industry. Thus it is now the world's oldest existing space advocacy body. When originally formed in October 1933, the BIS aimed not only to promote and raise the public profile of astronautics, but also to undertake practical experimentation into rocketry along similar lines to the organisations above ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freeman Dyson
Freeman John Dyson (15 December 1923 – 28 February 2020) was an English-American theoretical physicist and mathematician known for his works in quantum field theory, astrophysics, random matrices, mathematical formulation of quantum mechanics, condensed matter physics, nuclear physics, and engineering. He was Professor Emeritus in the Institute for Advanced Study in Princeton and a member of the Board of Sponsors of the Bulletin of the Atomic Scientists. Dyson originated several concepts that bear his name, such as Dyson's transform, a fundamental technique in additive number theory, which he developed as part of his proof of Mann's theorem; the Dyson tree, a hypothetical genetically engineered plant capable of growing in a comet; the Dyson series, a perturbative series where each term is represented by Feynman diagrams; the Dyson sphere, a thought experiment that attempts to explain how a spacefaring, space-faring civilization would meet its energy requirements with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kinetic Energy
In physics, the kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes. The same amount of work is done by the body when decelerating from its current speed to a state of rest. Formally, a kinetic energy is any term in a system's Lagrangian which includes a derivative with respect to time. In classical mechanics, the kinetic energy of a non-rotating object of mass ''m'' traveling at a speed ''v'' is \fracmv^2. In relativistic mechanics, this is a good approximation only when ''v'' is much less than the speed of light. The standard unit of kinetic energy is the joule, while the English unit of kinetic energy is the foot-pound. History and etymology The adjective ''kinetic'' has its roots in the Greek word κίνησις ''kinesis'', m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deep Impact (film)
''Deep Impact'' is a 1998 American science-fiction disaster film directed by Mimi Leder, written by Bruce Joel Rubin and Michael Tolkin, and starring Robert Duvall, Téa Leoni, Elijah Wood, Vanessa Redgrave, Maximilian Schell, and Morgan Freeman. Steven Spielberg served as an executive producer of this film. It was released by Paramount Pictures in North America and by DreamWorks Pictures internationally on May 8, 1998. The film depicts the attempts to prepare for and destroy a wide comet set to collide with Earth and cause a mass extinction. ''Deep Impact'' was released in the same summer as a similarly themed film, ''Armageddon'', which fared better at the box office, while astronomers described ''Deep Impact'' as being more scientifically accurate. Both films were similarly received by critics, with ''Armageddon'' scoring 37% and ''Deep Impact'' scoring 46% on Rotten Tomatoes. ''Deep Impact'' grossed over $349 million worldwide on an $80 million production budget. It was the f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dirty Bomb
A dirty bomb or radiological dispersal device is a radiological weapon that combines radioactive material with conventional explosives. The purpose of the weapon is to contaminate the area around the dispersal agent/conventional explosion with radioactive material, serving primarily as an area denial device against civilians. It is not to be confused with a nuclear explosion, such as a fission bomb, which produces blast effects far in excess of what is achievable by the use of conventional explosives. Unlike the cloud of radiation from a typical fission bomb, a dirty bomb’s radiation can be dispersed only within a few hundred meters or a few miles of the explosion. Dirty bombs have never been used, only tested. They are designed to disperse radioactive material over a certain area. They act through the effects of radioactive contamination on the environment and related health effects of radiation poisoning in the affected populations. The containment and decontamination of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Weapon Design
Nuclear weapon designs are physical, chemical, and engineering arrangements that cause the physics package of a nuclear weapon to detonate. There are three existing basic design types: * pure fission weapons, the simplest and least technically demanding, were the first nuclear weapons built and have so far been the only type ever used in warfare (by the United States on Empire of Japan, Japan during World War II, WWII). * boosted fission weapons increase yield beyond that of the implosion design by using small quantities of fusion fuel to enhance the fission chain reaction. Boosting can more than double the weapon's fission energy yield. * thermonuclear weapon, staged thermonuclear weapons are essentially arrangements of two or more "stages", most usually two. The first stage is normally a boosted fission weapon as above (except for the earliest thermonuclear weapons, which used a pure fission weapon instead). Its detonation causes it to shine intensely with x-radiation, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hormesis
Hormesis is a characteristic of many biological processes, namely a biphasic or triphasic response to exposure to increasing amounts of a substance or condition. Within the hormetic zone, the biological response to low exposures to toxins and other stressors is generally favorable. The term "hormesis" comes from Greek ''hórmēsis'' "rapid motion, eagerness", itself from ancient Greek ''hormáein'' "to set in motion, impel, urge on", the same Greek root as the word ''hormone''. The term 'hormetics' has been proposed for the study and science of hormesis. In toxicology, hormesis is a dose response phenomenon to xenobiotics or other stressors characterized by a low-dose stimulation, with zero dose and high-dose inhibition, thus resulting in a J-shaped or an inverted U-shaped dose response (e.g. the arms of the "U" are inhibitory or toxic concentrations whereas the curve region stimulates a beneficial response.) Generally speaking, hormesis pertains to the study of benefits of exposu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fallout
Nuclear fallout is the residual radioactive material propelled into the upper atmosphere following a nuclear blast, so called because it "falls out" of the sky after the explosion and the shock wave has passed. It commonly refers to the radioactive dust and ash created when a nuclear weapon explodes. The amount and spread of fallout is a product of the size of the weapon and the altitude at which it is detonated. Fallout may get entrained with the products of a pyrocumulus cloud and fall as black rain (rain darkened by soot and other particulates, which fell within 30–40 minutes of the atomic bombings of Hiroshima and Nagasaki). This radioactive dust, usually consisting of fission products mixed with bystanding atoms that are neutron-activated by exposure, is a form of radioactive contamination. Types of fallout Fallout comes in two varieties. The first is a small amount of carcinogenic material with a long half-life. The second, depending on the height of detonation, is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linear No-threshold Model
The linear no-threshold model (LNT) is a dose-response model used in radiation protection to estimate stochastic health effects such as radiation-induced cancer, genetic mutations and teratogenic effects on the human body due to exposure to ionizing radiation. The model statistically extrapolates effects of radiation from very high doses (where they are observable) into very low doses, where no biological effects may be observed. The LNT model lies at a foundation of a postulate that all exposure to ionizing radiation is harmful, regardless of how low the dose is, and that the effect is cumulative over lifetime. The LNT model is commonly used by regulatory bodies as a basis for formulating public health policies that set regulatory dose limits to protect against the effects of radiation. The model has also been used in the assessment of cancer risks of mutagenic chemicals. The validity of the LNT model, however, is disputed, and other significant models exist: the threshold mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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