NationMaster - Encyclopedia: Project Orion (nuclear propulsion)

Project Orion was the first engineering design study of a spacecraft powered by nuclear pulse propulsion, an idea first proposed by Stanisław Ulam in 1947. The project, initiated in 1958, was led by Ted Taylor at General Atomics and physicist Freeman Dyson, who at Taylor's request took a year away from Princeton's Institute for Advanced Study to work on the project. The first such think-tank of its kind since the Manhattan Project, Project Orion is recalled by many of its team as representing the best years of their lives.^{[citation needed]} Image File history File links NASA-project-orion-artist. ... Image File history File links NASA-project-orion-artist. ... The Space Shuttle Discovery as seen from the International Space Station. ... An artists conception of the Orion basic spacecraft, powered by nuclear pulse propulsion. ... StanisÅ‚aw Ulam in the 1950s. ... Ted Taylor (1925–2004), was a prominent U.S. physicist. ... General Atomics is a nuclear physics and defense contractor headquartered in San Diego, California. ... Freeman John Dyson FRS (born December 15, 1923) is an English-born American theoretical physicist and mathematician, famous for his work in quantum mechanics, solid-state physics, nuclear weapons design and policy, and for his serious theorizing in futurism and science fiction concepts, including the search for extraterrestrial intelligence. ... This article is about the World War II nuclear project. ...

By using energetic nuclear power, Orion offered both high thrust and high specific impulse — the holy grail of spacecraft propulsion. It offered performance greater than the most advanced conventional or nuclear rocket engines now under study. Cheap interplanetary travel was the goal of the Orion Project. Its supporters felt that it had great potential for space travel, but it lost political approval because of concerns with fallout from its propulsion. The Partial Test Ban Treaty of 1963 is generally acknowledged to have ended the project. Specific impulse (usually abbreviated Isp) is a way to describe the efficiency of rocket and jet engines. ... The Treaty Banning poop, in Outer Space, and Under Water, often abbreviated as the Partial Test Ban Treaty (PTBT), Limited Test Ban Treaty (LTBT), or Nuclear Test Ban Treaty (NTBT), although the former also refers to the Comprehensive Test Ban Treaty (CTBT), is a treaty intended to obtain an agreement... For other uses, see 1963 (disambiguation). ...

Nuclear power

Stanisław Ulam realized that nuclear explosions could not yet be realistically contained in a combustion chamber. Such a project did briefly exist, named Helios, but its theoretical performance was so poor that it never got beyond the drawing board. StanisÅ‚aw Ulam in the 1950s. ...

Instead, the Orion design would have worked by dropping fission or thermonuclear explosives out the rear of a vehicle, detonating them 200 feet (60 m) out, and catching the blast with a thick steel or aluminum pusher plate. For the generation of electrical power by fission, see Nuclear power plant. ... At the end of the 20th century, Thermonuclear has came to imply anything which has to do with fusion nuclear reactions which are triggered by particles of thermal energy. ...

Large multi-story high shock absorbers (pneumatic springs) were to have absorbed the impulse from the plasma wave as it hit the pusher plate, spreading the millisecond shock wave over several seconds and thus giving an acceptable ride. The long arm pistons proved one of the most difficult design features but many members of the team said that this seemed solvable. Low pressure gas bags were also proposed as a primary shock absorber. The two sets of shock absorption systems were tuned to different frequencies to avoid resonance. A shock absorber is a mechanical device designed to smooth out or damp a sudden shock impulse and dissipate kinetic energy. ... Pneumatics, from the Greek πνευματικός (pneumatikos, coming from the wind) is the use of pressurized air in science and technology. ... For other uses, see Spring. ... A plasma is a quasineutral, electrically conductive fluid. ... For the American composer, see Walter Piston. ... Sine waves of various frequencies; the lower waves have higher frequencies than those above. ... This article is about resonance in physics. ...

One aspect of the proposed vessel seems counter-intuitive today: because of the force involved in the thermonuclear detonations and the need to absorb the energy without harm, massive vessel designs were actually more efficient. Early designs had crew compartments and storage areas that were several stories tall, as opposed to contemporary chemical rockets whose height was almost all multi-stage fuel tanks with relatively little payload. A remote camera captures a close_up view of a Space Shuttle Main Engine during a test firing at the John C. Stennis Space Center in Hancock County, Mississippi Spacecraft propulsion is used to change the velocity of spacecraft and artificial satellites, or in short, to provide delta_v. ... For other uses, see Fuel (disambiguation). ...

Reaction mass for Orion would have been built into the bombs or dropped between 'pulses' to provide thrust. Polyethylene masses, garbage and sewage were all considered for use as reaction mass. Working mass is a mass against which a system operates in order to produce acceleration. ... Thrust is a reaction force described quantitatively by Newtons Second and Third Laws. ... This article does not cite any references or sources. ...

The smallest 4000 ton model planned for ground launch from Jackass Flats, Nevada had each blast add 30 mph (50 km/h) to the craft's velocity. A graphite based oil was to be sprayed on the pusher plate before each explosion to prevent ablation of the pusher plate. This sequence would be repeated thousands of times, like an atomic pogo stick. Jackass Flats, Nevada (USA) is located at coordinates latitude 36. ... This article is about velocity in physics. ... For other uses, see Graphite (disambiguation). ... Ablation is defined as the removal of material from the surface of an object by vaporization, chipping, or other erosive processes. ... An adult using a Pogo Stick A pogo stick is a device consisting of a pole with a handle at one end, footpads on the other and a spring which supports the stick and user when on the ground. ...

Orion's potential performance was stunning, at least compared to today's chemical or even other nuclear designs. Jerry Pournelle, who is acquainted with the project and its ex-team leader Freeman Dyson, has been quoted as saying that a single mission could have provided us with a large permanent moon base.^{[citation needed]} Alternatively an Orion could reach Pluto and return to Earth inside of a year. Single stage to Mars and back also seemed to be possible.^{[citation needed]} Jerry Eugene Pournelle, Ph. ... Freeman John Dyson FRS (born December 15, 1923) is an English-born American theoretical physicist and mathematician, famous for his work in quantum mechanics, solid-state physics, nuclear weapons design and policy, and for his serious theorizing in futurism and science fiction concepts, including the search for extraterrestrial intelligence. ...

Background

In the 1954 Operation Castle nuclear test series at Bikini Atoll, a crucial experiment by Lew Allen proved that nuclear explosives could be used for propulsion. Two graphite-covered steel spheres were suspended near the test article for the Castle Bravo shot. After the explosion, they were found intact some distance away, proving that engineered structures could survive a nuclear fireball. Year 1954 (MCMLIV) was a common year starting on Friday (link will display full 1954 Gregorian calendar). ... Operation Castle was the highest-yield nuclear test series ever conducted by the United States. ... The Flag of Bikini Atoll Bikini Atoll (also known as Pikinni Atoll) is an uninhabited 6. ... General Lew Allen, Jr. ... The first nuclear weapons, though large, cumbersome and inefficient, provided the basic design building blocks of all future weapons. ... For other uses, see Graphite (disambiguation). ... For other uses, see Steel (disambiguation). ... A black-and-white photograph of the Castle Bravo mushroom cloud. ...

Performance

The Orion nuclear pulse drive combines a very high exhaust velocity, from 20,000 to 30,000,000 m/s, with meganewtons of thrust. Many spacecraft propulsion drives can achieve one of these or the other, but nuclear pulse rockets are the only existing technology that delivers both (see spacecraft propulsion for more speculative systems). Specific impulse measures how much thrust can be derived from a given mass of fuel, and is the standard figure of merit for rocketry. For other uses, see Newton (disambiguation). ... A remote camera captures a close-up view of a Space Shuttle Main Engine during a test firing at the John C. Stennis Space Center in Hancock County, Mississippi Spacecraft propulsion is any method used to change the velocity of spacecraft and artificial satellites. ... Specific impulse (usually abbreviated Isp) is a way to describe the efficiency of rocket and jet engines. ...

Unmanned Orion-style nuclear pulse rockets can tolerate very large accelerations. A human-crewed Orion, however, must use damped springs behind the pusher plate to smooth the instantaneous acceleration to a level that humans can withstand–typically about 1–3

g

The high performance depends on the high exhaust velocity, in order to maximize the rocket's force for a given mass of propellant. The velocity of the plasma debris is proportional to the square root of the change in the temperature (

T c

) of the nuclear fireball. Since fireballs routinely achieve ten million degrees Celsius^{[citation needed]} or more in less than a millisecond, they create very high velocities. However, a practical design must also limit the destructive radius of the fireball. The diameter of the nuclear fireball is proportional to the square root of the bomb's explosive yield.

The shape of the bomb's reaction mass is critical to efficiency. The original project designed bombs with a reaction mass made of tungsten. The bomb's geometry and materials focused the x-rays and plasma from the core of nuclear explosive to hit the reaction mass. For other uses, see Tungsten (disambiguation). ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz...

A bomb with a cylinder of reaction mass expands into a flat, disk-shaped wave of plasma when it explodes. A bomb with a disk-shaped reaction mass expands into a far more efficient cigar-shaped wave of plasma debris. The cigar shape focuses much of the plasma on the pusher-plate.

A 10 kiloton of TNT equivalent atomic explosion will achieve a plasma debris velocity of about 100,000 m/s, and the destructive plasma fireball is only about 100 meters in diameter. A 1 megaton of TNT explosion will have a plasma debris velocity of about 10,000,000 m/s but the diameter of the plasma fireball will be about 1000 m. A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ...

The maximum effective specific impulse,

I s p

, of an Orion nuclear pulse drive generally is equal to:

where

C 0

is the collimation factor (what fraction of the explosion plasma debris will actually hit the impulse absorber plate when a pulse unit explodes),

V e

is the nuclear pulse unit plasma debris velocity, and

g n

is the standard acceleration of gravity (9.81 m/s²; this factor is not necessary if

I s p

is measured in N·s/kg or m/s). A collimation factor of nearly 0.5 can be achieved by matching the diameter of the pusher plate to the diameter of the nuclear fireball created by the explosion of a nuclear pulse unit.

Sizes of Orion vehicles

A 1959 report by General Atomics^[1] explored the parameters of three different sizes of hypothetical Orion spacecraft: A hypothesis (= assumption in ancient Greek) is a proposed explanation for a phenomenon. ...

The biggest design above is the "super" Orion design; at 8 million tons, it could easily be a city.^[2] In interviews, the designers contemplated the large ship as a possible interstellar ark. This extreme design could be built with materials and techniques that could be obtained in 1958 or were anticipated to be available shortly after. The practical upper limit is likely to be higher with modern materials. To meet Wikipedias quality standards, this article or section may require cleanup. ... Jan. ...

Most of the three tons of each of the "super" Orion's propulsion units would be inert material such as polyethylene, or boron salts, used to transmit the force of the propulsion unit's detonation to the Orion's pusher plate, and absorb neutrons to minimize fallout. One design proposed by Freeman Dyson for the "Super Orion" called for the pusher plate to be composed primarily of uranium or a transuranic element so that upon reaching a nearby star system the plate could be converted to nuclear fuel.^{[citation needed]} This article does not cite any references or sources. ... For other uses, see Boron (disambiguation). ... Freeman John Dyson FRS (born December 15, 1923) is an English-born American theoretical physicist and mathematician, famous for his work in quantum mechanics, solid-state physics, nuclear weapons design and policy, and for his serious theorizing in futurism and science fiction concepts, including the search for extraterrestrial intelligence. ... This article needs additional references or sources to facilitate its verification. ...

Applications

The Orion nuclear pulse rocket design has extremely high performance. Orion nuclear pulse rockets using nuclear fission type pulse units were originally intended for use on interplanetary space flights.

The top cruise velocity that can be achieved by a thermonuclear Orion starship is about 8% to 10% of the speed of light (0.08–0.1c). An atomic (fission) Orion can achieve perhaps 3%–5% of the speed of light.^{[citation needed]} A nuclear pulse drive starship powered by matter-antimatter pulse units would be theoretically capable of obtaining a velocity between 50% to 80% of the speed of light.^{[citation needed]} A line showing the speed of light on a scale model of Earth and the Moon, taking about 1â…“ seconds to traverse that distance. ... For other senses of this term, see antimatter (disambiguation). ... A line showing the speed of light on a scale model of Earth and the Moon, taking about 1â…“ seconds to traverse that distance. ...

Missions that were designed for an Orion vehicle in the original project included single stage (i.e., directly from Earth's surface) to Mars and back, and a trip to one of the moons of Saturn.

One possible modern mission for this near-term technology would be to deflect an asteroid that could collide with Earth. The extremely high performance would permit even a late launch to succeed, and the vehicle could effectively transfer a large amount of kinetic energy to the asteroid by simple impact. Also, an automated mission would eliminate the most problematic issues of the design: the shock absorbers.

Nuclear fission pulse unit powered Orions could provide a fast, economical interplanetary transportation with useful human crewed payloads of gargantuan mass.

Orion's technology is also one of very few interstellar space drives that could be constructed with known technology. Orion is the ideal method of propelling a multi-generational starship such as an interstellar ark to the stars at velocities of up to 10% of the velocity of light.

Even at 0.1c, Orion thermonuclear starships will require a flight time of 44 years to reach Proxima Centauri, the nearest star to the Sun, not counting time needed to reach that speed. At 0.1c, an Orion starship would require 100 years to travel 10 light years. The late astronomer Carl Sagan suggested that this would be an excellent use for current stockpiles of nuclear weapons. Proxima Centauri (Latin proximus, -a, -um: meaning next to or nearest to)[4] is a red dwarf star that is likely a part of the Alpha Centauri star system and is the nearest star to the Sun at a distance of 4. ... Sol redirects here. ... Insert non-formatted text here Carl Edward Sagan (November 9, 1934 â€“ December 20, 1996) was an American astronomer and astrobiologist and a highly successful popularizer of astronomy, astrophysics, and other natural sciences. ...

The first improved version of the Orion concept was designed by the British Interplanetary Society (B.I.S.) in the years 1973-1974. Project Daedalus was to be a robotic interstellar probe to Barnard's Star that would travel at 12% of the speed of light (0.12c). In 1989, an improved version of the original Daedalus design was created by the U.S. Navy in Project Longshot. The British Interplanetary Society (BIS) founded in 1933 by Mr. ... An artists conception of the British Interplanetary Society design for Project Daedalus Project Daedalus was a study conducted between 1973 and 1978 by the British Interplanetary Society to design a plausible interstellar unmanned spacecraft. ... Barnards Star is a very low-mass star in the constellation Ophiuchus which was discovered by the astronomer E. E. Barnard in 1916. ... Project Longshot is a design for an interstellar spaceship, an unmanned probe intended to fly to Alpha Centauri powered by nuclear pulse propulsion. ...

From 1998 to the present, the nuclear engineering department at Pennsylvania State University has been developing two improved versions of the Daedalus design known as Project Ican and Project Aimstar.^[3]

Economics

The expense of the fissionable materials required was thought high, until the physicist Ted Taylor proved that with the right designs for explosives, the amount of fissionables used on launch was close to constant for every size of Orion from 2,000 tons to 8,000,000 tons. The larger bombs used more explosives to super-compress the fissionables, reducing fallout. The extra debris from the explosives also serves as additional propulsion mass. Ted Taylor (1925–2004), was a prominent U.S. physicist. ...

Project Daedalus later proposed fusion explosives (deuterium or tritium pellets) detonated by electron beam inertial confinement. This is the same principle behind inertial confinement fusion. However, theoretically, it might be scaled down to far smaller explosions, and require small shock absorbers. An artists conception of the British Interplanetary Society design for Project Daedalus Project Daedalus was a study conducted between 1973 and 1978 by the British Interplanetary Society to design a plausible interstellar unmanned spacecraft. ... Deuterium, also called heavy hydrogen, is a stable isotope of hydrogen with a natural abundance in the oceans of Earth of approximately one atom in 6500 of hydrogen (~154 PPM). ... Inertial confinement fusion using lasers rapidly progressed in the late 1970s and early 1980s from being able to deliver only a few joules of laser energy (per pulse) to a fusion target to being able to deliver tens of kilojoules to a target. ...

Vehicle architecture

From 1957 until 1964 this information was used to design a spacecraft propulsion system called "Orion" in which nuclear explosives would be thrown through a pusher-plate mounted on the bottom of a spacecraft and exploded underneath. The shock wave and radiation from the detonation would make an impact against the underside of the pusher plate, giving it a powerful "kick," and the pusher plate would be mounted on large two-stage shock absorbers which would transmit the acceleration to the rest of the spacecraft in a smooth manner. Image File history File links Question_book-3. ... Year 1957 (MCMLVII) was a common year starting on Tuesday (link displays the 1957 Gregorian calendar). ... Also Nintendo emulator: 1964 (emulator). ... Gasfilled Shock absorber. ...

Radiation shielding for the crews was thought to be a problem, but on ships with mass greater than a thousand tons, the structural bulk of the ship, its stores, and the mass of the bombs and propellent provides shielding for the crew from most of the explosives' radiation. Radiation shielding effectiveness increases exponentially with shield thickness (see gamma ray for a discussion of shielding). This article is about electromagnetic radiation. ...

At low altitudes, during take-off, the fallout would be highly radioactive, and there was a grave danger of fluidic shrapnel being reflected from the ground. The solution was to use a flat plate of conventional explosives spread over the pusher plate, and detonate these to lift the ship from the ground before going nuclear. This would lift the ship far enough into the air that a focused nuclear blast would avoid harming the ship.

A preliminary design for the explosives was produced. It used a fusion-boosted fission explosive. The explosive was wrapped in a beryllium oxide "channel filler", which was surrounded by a uranium radiation mirror. The mirror and channel filler were open ended, and in this open end a flat plate of tungsten propellant was placed. The whole thing was wrapped in a can so that it could be handled by machinery scaled-up from a soft-drink vending machine. R-phrases , , , , , S-phrases , Flash point Non-flammable Related Compounds Other anions Beryllium telluride Other cations Magnesium oxide Calcium oxide Supplementary data page Structure and properties n, Îµr, etc. ... This article is about the chemical element. ... For other uses, see Tungsten (disambiguation). ...

At 1 microsecond after ignition, the gamma bomb plasma and neutrons would heat the channel filler, and be somewhat contained by the uranium shell. At 2-3 microseconds, the channel filler would transmit some of the energy to the propellant, which would vaporize. The flat plate of propellant would form a cigar-shaped explosion aimed at the pusher plate.

The plasma would cool to 14,000 °C, as it traversed the 25 m distance to the pusher plate, and then reheat to 67,000 °C, as (at about 300 microseconds) it hit the pusher plate and recompressed. This temperature emits ultraviolet, which is poorly transmitted through most plasmas. This helps keep the pusher plate cool. The cigar shape and low density of the plasma reduces the shock to the pusher plate.

The pusher plate's thickness was to decrease by about a factor of 6 from the center to the edge, so that the net velocity of the inner and outer parts of the plate are the same, even though the momentum transferred by the plasma increases from the center outwards.^{[citation needed]}

At low altitudes where the surrounding air is dense, gamma scattering could potentially harm the crew. The plan to solve this was to have takeoff stations in inner rooms shielded by supplies and equipment. Such a radiation refuge is necessary anyway on long missions to survive solar flares. In physics, Compton scattering or the Compton effect, is the decrease in energy (increase in wavelength) of an X-ray or gamma ray photon, when it interacts with matter. ... A solar flare observed by Hinode in the G-band. ...

Stability was thought to be a problem due to random placement errors of the bombs, but it was later shown that over time the random errors would tend to cancel out.

A one-meter model using RDX (chemical explosives), called "putt-putt", flew a controlled flight for 23 seconds to a height of 56 meters at Point Loma. RDX redirects here. ...

The shock absorber was at first merely a ring-shaped airbag. However, if an explosion should fail, the 1000 ton pusher plate would tear away the airbag on the rebound. A two-stage, detuned shock absorber design proved more workable. On the reference design, the mechanical absorber was tuned to 1/2 the pulse frequency, and the air-bag absorber was tuned to 4.5 times the pulse frequency.

Another problem was finding a way to push the explosives past the pusher plate fast enough that they would explode 20 to 30 m beyond it, and do so every 1.1 seconds. The final reference design used a gas gun to shoot the devices through a hole in the pusher plate.

Potential problems

Exposure to repeated nuclear blasts raises the problem of ablation (erosion) of the pusher plate. However, calculations and experiments indicate that a steel pusher plate would ablate less than 1 mm if unprotected. If sprayed with an oil, it need not ablate at all (this was discovered by accident; a test plate had oily fingerprints on it, and the fingerprints suffered no ablation). The absorption spectra of carbon and hydrogen minimize heating. The design temperature of the shockwave, 67,000 °C, emits ultraviolet. Most materials and elements are opaque to ultraviolet, especially at the 340 MPa pressures the plate experiences. This prevents the plate from melting or ablating. Image File history File links Question_book-3. ... For other uses, see Carbon (disambiguation). ... This article is about the chemistry of hydrogen. ... For other uses, see Ultraviolet (disambiguation). ...

One issue that remained unresolved at the conclusion of the project was whether the turbulence created by the combination of the propellant and ablated pusher plate would dramatically increase the total ablation of the pusher plate. According to Freeman Dyson, during the 1960s they would have had to actually perform a test with a real nuclear explosive to determine this; with modern simulation technology, this could be determined fairly accurately without such empirical investigation. Freeman John Dyson FRS (born December 15, 1923) is an English-born American theoretical physicist and mathematician, famous for his work in quantum mechanics, solid-state physics, nuclear weapons design and policy, and for his serious theorizing in futurism and science fiction concepts, including the search for extraterrestrial intelligence. ... The 1960s decade refers to the years from the beginning of 1960 to the end of 1969. ...

Another potential problem with the pusher plate is that of spalling–shards of metal potentially flying off the top of the plate. Very high speed photography of a small projectile impacting a thin aluminium plate at 7000 m/s. ...

True engineering tests of the vehicle systems were said to be impossible because several thousand nuclear explosions could not be performed in any one place. However, experiments were designed to test pusher plates in nuclear fireballs. Long-term tests of pusher plates could occur in space. Several of these tests almost flew. The shock-absorber designs could be tested at full-scale on Earth using chemical explosives.

But the main unsolved problem for a launch from the surface of the Earth is nuclear fallout. Freeman Dyson, group leader on the project, estimated back in the '60s that with conventional nuclear weapons, each launch would cause fatal cancers in ten human beings from the fallout (note that this estimate is disputed–see radiation hormesis). The United States Government concurred and decided that because of the danger to human life and the danger to electronic systems on the ground (from electromagnetic pulse) to shelve the project. Fallout is the residual radiation hazard from a nuclear explosion, so named because it falls out of the atmosphere into which it is spread during the explosion. ... The mushroom cloud of the atomic bombing of Nagasaki, Japan, 1945, rose some 18 km (11 mi) above the epicenter. ... Radiation hormesis is the theory that low doses of ionizing radiation are beneficial. ... The term electromagnetic pulse (EMP) has the following meanings: electromagnetic radiation from an explosion (especially a nuclear explosion) or an intensely fluctuating magnetic field caused by Compton-recoil electrons and photoelectrons from photons scattered in the materials of the electronic or explosive device or in a surrounding medium. ...

The magnetosphere would carry fissionables back to earth unless the spaceship were launched from a polar region such as Antarctica. This would require enormous legal changes as the continent is presently an international wildlife preserve.

Orion-style nuclear pulse rockets can be launched from above the magnetosphere so that charged ions of fallout in its exhaust plasma are not trapped by the Earth's magnetic field and are not returned to Earth. A magnetosphere is the region around an astronomical object in which phenomena are dominated or organized by its magnetic field. ...

The fallout for the entire launch of a 6000 short ton (5500 metric ton) Orion is only equal to a ten-megaton (40 petajoule) blast, assuming the use of pure fission weapon-type nuclear explosives. The short ton is a unit of mass equal to 907. ... A tonne (also called metric ton) is a non-SI unit of mass, accepted for use with SI, defined as: 1 tonne = 103 kg (= 106 g). ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... The joule (symbol J, also called newton metre, or coulomb volt) is the SI unit of energy and work. ...

With special designs of the nuclear explosive, Ted Taylor estimated that it could be reduced tenfold, or even to zero if a pure fusion explosive could be constructed^{[citation needed]}. Ted Taylor (1925–2004), was a prominent U.S. physicist. ...

The vehicle and its test program would violate the Partial Test Ban Treaty of 1963 as currently written, which prohibited all nuclear detonations except those which were conducted underground, both as an attempt to slow the arms race and to limit the amount of radiation in the atmosphere caused by nuclear detonations. There was an effort by the US government to put an exception into the 1963 treaty to allow for the use of nuclear propulsion for spaceflight, but Soviet fears about military applications kept the exception out of the treaty. The Treaty Banning poop, in Outer Space, and Under Water, often abbreviated as the Partial Test Ban Treaty (PTBT), Limited Test Ban Treaty (LTBT), or Nuclear Test Ban Treaty (NTBT), although the former also refers to the Comprehensive Test Ban Treaty (CTBT), is a treaty intended to obtain an agreement...

One way around the restrictions of the treaty would be to use a form of the Daedalus fusion microexplosion rocket. Daedalus class systems use pellets of one gram or less ignited by particle or laser beams to produce very small fusion explosions with a maximum explosive yield of only 10–20 tons of TNT equivalent.

The launch of such an Orion nuclear bomb rocket from the ground or from low Earth orbit would generate an electromagnetic pulse that could cause significant damage to computers and satellites, as well as flooding the van Allen belts with high-energy radiation. This problem might be solved by launching from very remote areas, because the EMP footprint would be only a few hundred miles wide. The Earth is well-shielded from the Van Allen belts. In addition, a few relatively small space-based conductive tethers could be deployed to quickly eject the energetic particles from the capture angles of the Van Allen belts. A low Earth orbit (LEO) is an orbit in which objects such as satellites are below intermediate circular orbit (ICO) and far below geostationary orbit, but typically around 350 - 1400 km above the Earths surface. ... The term electromagnetic pulse (EMP) has the following meanings: electromagnetic radiation from an explosion (especially a nuclear explosion) or an intensely fluctuating magnetic field caused by Compton-recoil electrons and photoelectrons from photons scattered in the materials of the electronic or explosive device or in a surrounding medium. ... This article is about the machine. ... This article is about artificial satellites. ... Van Allen radiation belts The Van Allen Radiation Belt is a torus of energetic charged particles (plasma) around Earth, held in place by Earths magnetic field. ... Artists conception of satellite with a tether Tether propulsion uses long, strong strings (known as tethers) to change the orbits of spacecraft. ...

Assembling a pulse drive spacecraft in orbit by more conventional means and only activating its main drive at a safer distance would be a less destructive approach. The space elevator hypothetically provides an excellent solution, but is currently impossible because existing materials such as carbon nanotubes do not have sufficient tensile strength. Existing chemical rocket designs are extremely inefficient (and expensive) when launching mass into orbit. Furthermore, it is unlikely that lifting the immense Orion into orbit in one piece would even be possible, unless multiple elevators or rockets were used in tandem. Adverse public reaction to any use of nuclear explosives is likely to remain a hindrance even if all practical and legal difficulties are overcome. A space elevator would consist of a cable anchored to the Earths surface, reaching into space. ... An electronic device known as a diode can be formed by joining two nanoscale carbon tubes with different electronic properties. ... Tensile strength isthe measures the force required to pull something such as rope, wire, or a structural beam to the point where it breaks. ...

Urban Legends

According to an urban legend, a test similar to the test of a pusher plate apparently occurred as an accidental side effect of a nuclear containment test called "Pascal B" conducted on 27 August 1957.^[4] The test's experimental designer Dr. Brownlee performed a highly approximate calculation that suggested that the low-yield nuclear explosive would accelerate the massive (900 kg) steel capping plate to six times escape velocity.^[5] The plate was never found, and Dr. Brownlee believes that the plate never left the atmosphere (for example it could have been vaporized by compression heating of the atmospheric due to its high speed.) The calculated velocity was sufficiently interesting that the crew trained a high-speed camera on the plate, which unfortunately only appeared in one frame, but this nevertheless gave a very high lower bound for the speed. However the concept of propelling plates with explosives is similar. The Smoky shot of Operation Plumbbob. ... Space Shuttle Atlantis launches on mission STS-71. ...

Appearances in fiction

An early appearance of an Orion-style nuclear pulse propelled rocket in science fiction was in the science fiction novel Empire of the Atom written by A. E. Van Vogt in 1956. In this novel there is a post-atomic-war interplanetary empire called the Empire of Lyn that uses Orion-type nuclear rockets for interplanetary spaceflight. In the story the past atomic war was an interstellar war fought between humans and hostile aliens from another star somewhere between 800 and 8000 years before. Alfred Elton van Vogt (April 26, 1912 â€“ January 26, 2000) was a Canadian-born science fiction author who was one of the most prolific, yet complex, writers of the mid-twentieth century Golden Age of the genre. ...

Early versions of 2001: A Space Odyssey had a ship (Discovery One) using this drive. The final vehicle did not use this idea since Stanley Kubrick was fed up with nuclear bombs after making Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb. United States Spacecraft Discovery One is a fictional spacecraft appearing in The Space Odyssey series, including the movie 2001: A Space Odyssey. ... Kubrick redirects here. ... For the hit 1987 single by Depeche Mode, see the album Music for the Masses Film poster for Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb is a 1964 satirical film directed by Stanley Kubrick. ...

In Jerry Pournelle and Larry Niven's Hugo-nominated novel Footfall, an Orion vessel is constructed as a last-resort weapon against an alien invasion. Jerry Eugene Pournelle, Ph. ... This article does not cite any references or sources. ... The 2005 Hugo Award with base designed by Deb Kosiba. ... Footfall is a 1985 science fiction novel written by Larry Niven and Jerry Pournelle. ...

In the novel King David's Spaceship, also by Pournelle, inhabitants of a planet that is to be readmitted as a colony world to the Empire plot to build the spaceship based on an Orion project concept in order to qualify their planet as a higher-developed, spacefaring, Class Two Imperial world. King Davids Spaceship is a novel by science fiction author Jerry Pournelle. ... The fictional CoDominium universe is a future history (now alternate history) setting for the books in the CoDominium Series by Jerry Pournelle. ...

The Star Trek:TOS episode "For the World is Hollow and I Have Touched the Sky" features a generation ship, constructed out of a hollowed-out iron asteroid, propelled using "Orion class nuclear pulse engines" in which fission bombs were detonated in shafts. It appeared to have been traveling for about 10,000 years, and had traveled about 30 light years on its own power. The starship Enterprise as it appeared on Star Trek Star Trek is a culturally significant science fiction television series created by Gene Roddenberry in the 1960s. ... For the World is Hollow and I Have Touched the Sky is a third season episode of Star Trek: The Original Series. ... A generation ship is a hypothetical starship that travels across great distances between stars at a speed much slower than that of light (see interstellar travel). ... A light year, abbreviated ly, is the distance light travels in one year: roughly 9. ...

The 1998 film Deep Impact featured a spacecraft named Messiah, which utilized the "Orion drive" and appears to be a variant of nuclear detonation propulsion. In the film, the drive is accredited to the Russians. Deep Impact is a 1998 science fiction disaster film released by Paramount Pictures and DreamWorks Pictures. ...

In the books Ilium and Olympos by Dan Simmons a space ship with Orion thrust is used to travel through the Solar System over the course of a week. For other uses, see Ilium. ... Dan Simmons novel Olympos, published in 2005, is the sequel to Ilium and final part of Ilium/Olympus duology. ... Dan Simmons (born April 4, 1948 in Peoria, Illinois) is an American author most widely known for his Hugo Award-winning science fiction novel Hyperion and its sequel The Fall of Hyperion. ...

The book Orion Shall Rise by Poul Anderson, part of his Maurai series of stories, featured a covert group within a resource-deprived, post-apocalyptic civilization resurrecting the Orion program to take humanity to the solar system and beyond. Orion Shall Rise is a science fiction novel by Poul Anderson, published in 1983. ... Poul William Anderson (November 25, 1926â€“July 31, 2001) was an American science fiction author of the genres Golden Age. ... Apocalyptic science fiction is a sub-genre of science fiction that is concerned with the end of civilization, through nuclear war, plague, or some other general disaster. ...

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