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Project orion
- 5. • Basic Design Basic Design – Containers of bomb/projectile packages – Dropped one by one through hole in pusher plate – Suspenstion system to cushion pusher plate shock on rest of craft – Ignition of bomb at fixed distance from pusher plate
- 7. Maximum Carry Capacity • Super-Orion – volume as large as 10 copies of Great Pyramid – 1 million metric tons • This is equivalent to 10 billion up to 100 kg people! • Several times the capacity of a the largest supertanker • Scalable – 300 tons to 8 million tons
- 8. Some Capabilities • A single Project Orion mission would have been sufficient to establish a large permanent moon base. • Project Orion aimed for a manned mission to Mars by 1965. • Project Orion aimed for a manned mission to Saturn by 1970. • A ship powered by the Orion drive could have travelled to Pluto and back to Earth in less than a year. • All components (except bombs) are reuseable • Could send entire cities to Mars
- 11. Objections • Fallout – Est. as 10 unnecessary deaths per launch by Freeman Dyson • Compare to deaths from fossil fuels, autos, phamacological mishaps.. • EMP • Treaty Problems • Tee up or Toss
- 13. Unmanned Orion • Acceleration bursts not a problem – No shock absorbers needed • Up to 3.3% light speed • Perfect for killer comet or asteroid deflection
Notes de l'éditeur
- A number of designs were proposed in the late 1940's and 1950's to get around the temperature limitation and to exploit the enormous power of the atomic bomb, estimated to be on the order of 10 billion horsepower for a moderate-sized device (8). The Martin Company designed a nuclear pulse rocket engine with a "combustion chamber" 130 feet in diameter. Small atomic bombs with yields under 0.1 kiloton (a kiloton is the energy equivalent of 1000 tons of the high explosive TNT) would have been dropped into this chamber at a rate of about one per second (9); water would have been injected to serve as propellant.
- Project Orion was born in 1958 at General Atomics in San Diego. The company, now a subsidiary of defense giant General Dynamics, was founded by Frederick de Hoffman to develop commercial nuclear reactors. The driving force behind Orion was Theodore Taylor, a veteran of the Los Alamos weapons programs. De Hoffman persuaded Freeman DysonTaylor's specialty at Los Alamos had been the effects of atomic weapons. He was an expert at making small bombs at a time when the drive was toward ever-bigger superweapons. He was also aware of techniques for shaping explosions, for making bomb debris squirt in one particular direction. Taylor adopted Ulam's pusher-plate idea but instead of the propellant disks he combined propellant and bomb into a single pulse unit. The propellant material of choice was plastic, probably polyethylene (15). Plastic is good at absorbing the neutrons emitted by an atomic explosion (i.e. it couples well with the prompt radiation energy) and in addition it breaks down into low-weight atoms such as hydrogen and carbon which move at high speeds when agitated. The advantage of the pusher plate design, as Taylor and Dyson saw it, was that it could simultaneously produce high thrust with high exhaust velocity. No other known propulsion system combined these two highly desirable features. The effective Isp could theoretically be as high as 10,000 to one million seconds (17). The calculated force exerted on the pusher plate was immense; it would have created intolerable acceleration for a manned vehicle. Therefore, a shock absorber system was placed between the plate and the vehicle itself. The impulse energy delivered to the plate was stored in the shock absorbers and released gradually to the vehicle.The Orion workers realized early that the U.S. government had to become involved if the project was to have any chance of progressing beyond the tinkering stage. Accordingly, the Advanced Research Projects Agency (ARPA - later DARPA with "D" standing for "Defense") was approached in April1958. In July, it agreed to sponsor the project at an initial funding level of $1 million per year; it was at this time that the code name of Orion was assigned (22). Work proceeded under ARPA order 6, task 3, entitled "Study of Nuclear-Pulse-Propelled Space Vehicles" (23).At a time when the U.S. was struggling to put a single man into orbit aboard a modified military rocket, Taylor and Dyson were developing plans for a manned voyage of exploration through much of the solar system. The original Orion design called for 2000 pulse units, far more than enough to attain Earth escape velocity. "Our motto was 'Mars by 1965, Saturn by 1970'", recalls Dyson (30).A crisis came in late 1959, when ARPA decided it could no longer support Orion on national-security grounds. Taylor had no choice but to approach the Air Force for funds. It was a hard sell. A common reaction from both military and civilian officials is displayed by the quote: "...you set off one big bomb and the whole shebang blows up."(34) The Air Force finally decided to take on Orion, but only on the condition that a military use be found for it. Dyson says that his Air Force contacts, although sympathetic to the goal of space exploration, felt that their hands were tied (35). One immediate result of the change of management was that all model flight testing was stopped (36). The freewheeling era was over; Taylor's dream of a company of "men of goodwill" exploring the solar system had died.Robert McNamara, Defense Secretary under the Kennedy Administration, realized that Orion was not a military asset. His department consistently rejected any increase in funding for the project, effectively limiting it to a feasibility study (37). Taylor and Dyson knew that another money source had to be found if a flyable vehicle was to be built. NASA was the only remaining option.The Saturn V would eventually transport men to the moon. The Orion workers had produced a new, "first generation" design that abandoned ground launch and instead would have been boosted into orbit as a Saturn V upper stage. The core of the vehicle was a 200,000-pound "propulsion module" with a pusher-plate diameter of 33 feet, limited by the diameter of the Saturn. This design limitation also restricted Isp to from 1800 to 2500 seconds (39). While disappointingly low by nuclear- pulse standards, this figure still far exceeded those of other nuclear rocket designs. The shock absorber system had two sections: a primary unit made up of toroidal pneumatic bags located directly behind the pusher plate, and a secondary unit of four telescoping shocks (like those on a car) connecting the pusher plate assembly to the rest of the spacecraft (40).How many Saturn V's would have been required to put this vehicle into orbit? Dyson says one or two (41); a simple inspection of published drawings indicates at least two, possibly three if the crew module (with crew aboard) was intended to be flown separately (42). In this case, some assembly would have been done on-orbit. Several mission profiles were contemplated; the one developed in greatest detail appears to have been a Mars flight. Eight astronauts, with around 100 tons of equipment and supplies, could have made a round trip to Mars in 125 days
- A hammer blow was delivered in August 1963 with the signing of the nuclear test-ban treaty by the U.S., U.K., and U.S.S.R. Orion was now illegal under international law. Yet the project did not die immediately. It was still possible that an exemption could be granted for programs that were demonstrably peaceful. Surely the treaty reduced Orion's political capital even further, though. Yet another problem was that, because Orion was a classified project, very few people in the engineering and scientific communities were aware of its existence. In an attempt to rectify this, Nance (now managing the project) lobbied the Air Force to declassify at least the broad outline of the work that had been done. Eventually it agreed, and Nance published a brief description of the "first generation" vehicle in October 1964 The Air Force, meanwhile, had become impatient with NASA's temporizing. It was willing to be a partner but only if NASA would contribute significant funds. Hard-pressed by the demands of Apollo, NASA made its decision in December 1964 and announced it publicly the following month: no money would be forthcoming (50). The Air Force then anounced the termination of all funding, and Orion quietly died. Some $11 million had been spent over nearly seven yearsOvershadowed by the moon race, Orion was forgotten by almost everybody except Freeman Dyson and Theodore Taylor. Dyson in particular seems to have been deeply affected by his experience. The story of Orion is important, he says, "...because this is the first time in modern history that a major expansion of human technology has been suppressed for political reasons"
- The basic Orion design: Helix-shaped containers house hydrogen bombs, to be ejected through a hole in its pusher plate. Photo courtesy of Henry Holt and CompanyThis approach, in tandem with the pusher plate concept, offered a unique propulsion system that could simultaneously produce high thrust with high exhaust velocity. The effective specific impulse could theoretically be as high as 10,000 to one million seconds. A series of abrupt jolts would be experienced by the pusher plate, so powerful that, if these forces were not spread out in time, they would result in acceleration surges that were intolerable for a manned vehicle. Consequently, a shock absorbing system was devised so that the impulse energy delivered to the plate could be stored and then gradually released to the vehicle as a whole.
- The Orion nuclear pulse drive combines a very high exhaust velocity, from 20 to 30 km/s, with meganewtons of thrust.[4] Many spacecraft propulsion drives can achieve one of these or the other, but nuclear pulse rockets are the only proposed technology that could potentially deliver bothSince weight is no limitation, an Orion craft can be extremely robust. An unmanned craft could tolerate very large accelerations, perhaps 100 g. A human-crewed Orion, however, must use some sort of damping system behind the pusher plate to smooth the instantaneous acceleration to a level that humans can comfortably withstand – typically about 2 to 4 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 (Tc) of the nuclear fireball. Since fireballs routinely achieve ten million degrees Celsius 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.
- http://www.oriondrive.com/The scientists working on Project Orion didn't just plan to send a few highly trained astronauts on space missions; they intended to go themselves to Saturn, in many cases taking their wives and children with them!
- On the Apollo missions, only 1/601 of the mass sent into space returned. An Orion mission to Mars would return 1/2.5 of its mass and a mission to Saturn would return 1/6 of its mass. In 1958 dollars, an Orion mission would have cost 11 cents per kilogram sent into space, while in 2005 dollars, it would cost 70 cents per kilogram (Farmbrough). More mass fraction would be cargo if you send it up one way.
- Orion orbiting MarsDespite its promise, and despite the fact that is was backed by many prominent figures in the physics and space community, Project Orion never progressed beyond research (the research indicated the project was entirely feasible). The project was outmanoeuvred by its opponents, and killed for political reasons.http://www.youtube.com/watch?v=E3Lxx2VAYi8http://onionesquereality.wordpress.com/2008/02/22/death-of-a-project-project-orion/http://www.ted.com/talks/george_dyson_on_project_orion.html
- http://www.youtube.com/watch?v=V1vKMTYa40A&feature=player_embeddedOne of the greatest appeals of Orion was that the bigger you made it, the better it worked. While chemical rockets scale badly - with big ones much harder to build than small ones - Orion was just the opposite. That meant that large spacecraft, capable of long missions, were not merely possible, but actually easier, for a variety of reasons, than small ones. Bigger spaceships meant more mass for absorbing radiation and shock, more room to store fuel, and so on.Could Orion ever come back? The answer is yes. The Test Ban Treaty is a real obstacle to any future deployment of Orion. However, it binds only a few nations, and many nations (like India and China) that are both nuclear-capable and interested in outer space have never signed it. For an up-and-coming country looking to seize the high ground in space in a hurry, Orion could have considerable appeal. And, of course, even the United States could withdraw from the Treaty, on three months' notice, under the Treaty's own terms.Orion's scientists weren't worried about fallout. Orion would have produced some, but the amount would have been tiny compared to what was being released already from above-ground tests, and there was hope that additional work would have produced even cleaner bombs designed specifically for propulsion. Today, people are much more nervous about radiation and under current political conditions a ground-launched Orion is a non-starter, at least in Western countries. But not everyone cares as much about radiation, and indeed the countries that worry about it the least are those most likely to find Orion appealing as a way to attain space supremacy over more established space powers in a hurry. What's "Orion" in Chinese?Nuclear Orion can achieve launch costs of less than $1/kg and perhaps a tiny fraction of that. This is 1000 to 20,000 times cheaper than current costs.
- http://www.oriondrive.com/p1_story_fallout.phpFallout and Typical OrionThe explosions for Orion that occur in the magnetosphere where the magnetic field lines lead back to earth is where fallout will come back down and be a problem.We have already studied that reducing the fission component of any bomb and getting to higher fusion purity greatly reduces fallout and also a north pole launch reduces the fallout that returns to earth. Having a pile of conventional explosives for the first pulse also helps since the ground contact explosion is messier than the air bursts.It would also seem best to send it up during a snow storm which would contain the fallout that coincides with a solar storm that flattens out the magnetosphere.If you could not make the pure fusion bombs, which has not been done yet then another way to further reduce the radiation is for an unmanned high-G sprint start to a point outside the magnetosphere zone. Another method is to use a large all chemical rocket that is able carry a smaller Orion into space where it is safe to light up the Orion.The tee up or toss. A toss would be to use a stack of chemical explosives to get the projectile moving a bit and clear of the ground when the nuclear charge goes off. A nuclear airburst has less fallout than a ground detonation. A tee-up would be to build a tower and have the projectile at the top and the nuclear charge at the proper distance below. Obviously the tower is utterly destroyed. Also, note that the initial charge or two would not count against any projectile or rocket cargo. It would always be outside.We could also size the projectile so that we go at about 1.5 times the earth escape velocity so that it is a straight shot into the moon. The metal projectile designed to also survive the lunar impact. Ta da cheap cargo delivery to the moon.an underground launch would contain most of the fallout and all of the blast. Any optional dome would be to capture any fallout that leaks from underground.http://nextbigfuture.com/2009/02/nuclear-orion-home-run-shot-all-fallout.html
- Please review the chart (click on pictures for a larger image) with the effects of different size nuclear explosions. Notice that the air eventually stops the nuclear explosion. The fireball stops after 1.1 kilometers because of air. The Orion tests showed that metal with ablative oil can be a few hundred feet away and not be damaged. The ablative oil vaporizes and takes care of the ultraviolet and soft x-rays. The metal has to be big enough to absorb the heat and not get to its melting temperature.
- An unmanned Orion asteroid interceptor was designed. It would not need shock absorbers. Artillery arming, fusing, firing system for shells are regularly built to take 1000 Gs.There was a three page paper: Nuclear explosive propelled Interceptor for deflecting objects on collision course with Earth. JohndaleSolem, Los Alamos, proposed unmanned vehicle. No shock absorber or shielding. The pulse units were 25kg bombs of 2.5 kiloton yield for 100G acceleration of a 3.3 ton Orion. So an unmanned nuclear Orion can survive very high G forces. A single 25 kiloton yield would accelerate 3.3 tons to 1000Gs. A 2.5 megaton yield would accelerate 330 tons by 1000Gs. 25 megaton yield would accelerate 3,300 tons by 1000Gs. The highest acceleration had 0.4 seconds between charges so to get up to speed two or three charges might be needed to get 1.2 seconds of acceleration. Earth escape velocity is 11.2 km/s. 1000Gs is 9.8km/s**2. A structure can be built that can contain the fallout from one or a few bombs.http://www.spacedaily.com/news/nuclearspace-03h.html