Talk:Project Orion (nuclear propulsion)

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Why is there no criticism section?192.235.29.95 15:09, 20 April 2006 (UTC)

Contents 1 Cancellation of Orion 2 Antimatter 3 100,000 vs 1,000,000 vs 10,000,000 m/s 4 Number of deaths per launch 5 International test ban treaty 6 External links 7 pure fusion nuke 8 Plumbob Shot 9 Name being recycled 10 Momentum increases or decreases??? 11 How much would it cost 12 Weight and efficiency 13 Helios 14 dates 15 References in Fiction 16 Question 17 Questions about speed vs number of bombs 18 Slowing down

[edit] Cancellation of Orion

Some text that I moved from another article but have no time to integrate:

In the year 1965 The U. S congress canceled funding for the Orion nuclear bomb pulse propulsion project because of widespread political opposition to it. It was very probably an extremely, foolish , stupid , short sited , and unwise decision for congress to cancel the Orion project in 1965. We need to beat our nuclear swords (nuclear weapons), that we made for fighting an atomic war ,or thermonuclear war of apocalypse into peaceful nuclear plow shares.

Reviving the Orion project may be best, and most productive way to do this. With Orions we can build a true space faring solar system wide civilization. We can even travel to the planets of other stars within 10 light years of the solar system and colonize them within a maximium of 100 years of flight time using multi-generational Orion thermonuclear starships that can accelerate up to 10 % of the velocity of light, and thus achieve interstellar space flight.

Some versions of the Orion Star Ship design can achieve only 3 % or 4% of light velocity , but other versions of the Orion StarShip can go faster.Look up the Orion starship, and learn more about it. Also look up the related Deadalas fusion microexplosion nuclear pulse rocket project.*

DJ Clayworth 21:06, 23 Jun 2005 (UTC)

Everytime you launch an Orion, ten people die, on average, from fallout. That's bad.

And it's not like the Shuttle which kills its own crew, you're killing uninvolved bystanders. People really hate dying for other peoples gain.

The zero-fallout nuclear bombs haven't appeared; and if I understand it, don't appear to work. If you're prepared to actively go out and kill innocent bystanders for your projects, I have a project that involves stopping you; that probably involves police officers and/or legal manoevers. WolfKeeper

You may want to take a look at how many people are killed by a coal power plant every year, or by exhaust from cars, or by hydrazine from existing spacecraft, or... oh, no, I forgot; nuclear is DIFFERENT, yes?

The quote "The Orion starship is the best possible use of the 100,000 + nuclear weapons currently stock piled on the planet Earth . This fact was observed by the late astronomer Carl Sagan in his book cosmos. Carl Sagan was 100% right about this." has a pretty strong POV bent to it. I've tried to change this to reflect the source, but remove to implicit approval. --Icelight 30 June 2005 23:15 (UTC)

The whole article really has a pro-Orion bent, rather than being a flat and neutral account of the project; I can understand why this is, because I grew up reading a lot of science fiction as well, and it would be lovely if Orion could be made to work. It's one of those 'underdog' subjects which people tend to be soft on, and coupled with the substantial overlap between science fiction enthusiasts and the people of Wikipedia this bias is perhaps inevitable. In my experience science fiction enthusiasts tend to be more interested in ideals, principles and the great sweep of human history than trivial practicalities and individual human beings; I was like that myself. The fact that Freeman Dyson's estimate of the people killed by an Orion launch is buried in the middle of the article, and then immediately pooh-poohed away, is testament to how little has changed. -Ashley Pomeroy 12:03, 19 August 2005 (UTC)

OK, we all agree that nuclear fallouts are bad! and most of all, politically incorrect. So why not revive Orion research/testing on the moon once (if ever!) we have a base there (alas, the moon is probably a 'denuclearized' zone? isn't it?). Obviously people will complain if we transport nuclear bombs to the moon or even if we build them there, but at least, theoretically this would solve the fallout and EMP problems! I was shocked when I saw this orion page (find it out after seeing some comments about the new NASA orion crew vehicle), I though relativistic speed were completely out of reach with known technology! But it's not! 1950s technology could do it! It's really frustrating! what a waste! --Edouard 12:08 September 4 2006 (WET)

"Everytime you launch an Orion, ten people die, on average, from fallout. That's bad" Obviusly the idea is to use such a propulsion system at a safe distance, where nobody would be afected by the nuclear fallout. Outer orbit or old nuclear bombs test areas would be the perfect zone for this. 18:58 10 September 2006 (Greenwich Time)

It would probably work better if we used chemical rockets to get into space and then used fusion bombs for acceleration, where the small nuclear fallout wouldn't be a problem. -Jay 360, 1:29 PM —Preceding unsigned comment added by Jay360 (talk • contribs) 20:29, 16 March 2008 (UTC)

But see then you run into the problem of that not being possible! And it's the same with the "launch it from the moon" theory. Do you not understand that the people who go on this spaceship have to live there for 100 years?! You need to make these people comfortable so they don't go crazy and screw up all that scientific work with their feuds with each other over living space. This brings up another issue, you cant ship that shit to the moon! You need shock absorbers several stories high, a """giant""" steel plate, several thousand nuclear bombs, and here's the kicker concrete for sheilding the crew! And you want to ship all that to the moon or into orbit?! Do you understand there probably isn't enough rocket fuel for that? Those things don't even take into consideration crew accomidations, which as I stated before would have to be comfortable. No, the only way you are building this thing is here on Earth. Plus even if you did make it to another planet in another solar system, any civilization you establish will die out in several generations anyways because the inbreeding would be so great that people would soon become infertile, because you can't ship enough people to have enough genetic diversity to stay alive. We need to stop worrying about going to other planets and start worrying about our own, at least until we can get that mess sorted out.Whodoesntlovemonkeys (talk) 01:15, 15 May 2008 (UTC)

[edit] Antimatter

I've deleted this bit on antimatter. My understanding is that antimatter is unbelievably expensive and inefficient to make; a 1/2 gram of antimatter is probably more than will ever be made.

The antimatter story forms one of the key elements in a Joe Haldeman novella, winning the 1977 Hugo-award. The quantity issue was solved by inventing an antimatter star. Anyway, the point is, people have thought about it, so it could get a place in the article Reynaert-ad 11:56, 1 June 2006 (UTC)

I went to a talk about a tiny unmanned antimatter ramjet UAV that somebody designed; it was to use micrograms of antimatter, and even that required orders of magnitude more production of antimatter than there has ever been, and probably would ever be.

The idea that you would launch a vehicle weighing thousands of tonnes; there's just no chance.

If you want to talk about antimatter for interstellar travel, that's fine, maybe you can build massive production facilities in space for it or something. But for Earth launch there's a stupendous gap between theory and practice that may very well be unbridgeable.

p.s. apparently the projected cost of antimatter is $25 billion per gram. You'd need thousands of grams to launch a space craft. Current production is 10 nanograms/year worldwide... maybe when CERN comes on line, maybe they might get up to micrograms/year, who knows? fagetaboutit WolfKeeper

"when CERN comes online"? CERN is an institute.

Meaning is clear, you're being deliberately obtuse; or perhaps you're not doing so deliberately.WolfKeeper

I would also like to mention that views like "more antimatter will never be produced" are incredibly narrow minded and dare I say stupid.

That's a straw man, I never said that. And it's not daring at all to insult people's views when you remain anonymous.WolfKeeper

Can you honestly say you think science will not improve the process?

Can you honestly say that it will, enough to make the difference? The current machines are enormous, the production rate negligable; as is the efficiency.WolfKeeper

To give actual numbers: Antimatter production efficiency in existing facilities is at about 10^-6 efficiency right now. Paper designs exist for facilities specifically optimized for mass production of antiprotons, but the best efficiency anyone thinks they can produce is about 10^-4. This is because lighter particles are produced preferentially to antiprotons, and antiprotons are composite particles (you'd have to create three quark/antiquark pairs of the right type and in the same place to make a proton/antiproton pair). The 10^-4 design assumes that all parameters are optimally tuned to favor antiproton production as much as possible. These numbers are generally interpreted as ruling out useful antimatter production for spacecraft. A dedicated 3 GW nuclear plant connected to a facility with a wall-plug efficiency of 10^-4 (which I don't think was the type of figure quoted) would produce about 100 micrograms per year. A useful interstellar probe would need tonnes (the probe has to be big enough to signal back to you, and that's very hard by any method over those distances). Probes that weren't designed for interstellar use could be built much more cheaply using something other than an antimatter drive.--Christopher Thomas 20:26, 17 November 2005 (UTC)

I suggest you read the "Angels and Demons" FAQ on the CERN website. It is very enlightening on the subject of antimatter, the main point being the enormous expentature of energy to create it, and then the conclusion that it would be impossible to go beyond pure 1:1 conversion, meaning you could never get more energy out of antimatter than you put in creating it. Add to the fact that holding together large (meaning, more than a few nanograms) would be impossible due to magnetic forces (you have to use charged antimatter, because you can't contain it with magnetic fields if it's neutral.) In short, Antimatter would be useless in an energy-generation or weaponized form. -Whursey 07:39, 27 December 2005 (UTC)

I suggest that you re-read my comment to make sure you understand it correctly. Antimatter is potentially useful as a fuel for spacecraft, because even though it has to be synthesized at horrible inefficiency (my quoted figure of 10^-4 to 10^-6, which you seem to have overlooked), it has the highest energy storage density of any available fuel (and so highest Isp). The reason it isn't practical for interstellar travel is that it's prohibitively expensive to produce enough to fuel a useful probe (though I'm not convinced the radiation problems are solvable either). --Christopher Thomas 08:52, 27 December 2005 (UTC)

This is very much correct. I have taken a detailed study looking at various advanced propulsion systems, and pretty much all antimatter systems proposed involve its use as a fusion igniter. Antimatter is a very lightweight method to induce fusion reactions, or so it is theorized. Burning antimatter alone would likely be far too impracticable. -dabman —Preceding unsigned comment added by 71.37.18.74 (talk • contribs) on 20:04, 12 January 2006

I've heard of these proposals, but I'm skeptical of them actually working in a useful way. Antimatter-induced _fission_ would probably work (boil one uranium nucleus, and have it spray off vast numbers of neutrons to trigger other atoms to fission), but as most of the energy in that scheme comes from fission, you're limited to fission exhaust velocities. The main benefit is that you can build a smaller high-thrust fission ship (low-thrust you do with a fission-powered electric drive). The amount of antimatter needed is reduced by 10³ to 10⁴, so it's still very, very expensive to do this. As a result, I'm not sure these craft are practical (depends on how much you need a small high-thrust fission craft).

Antimatter-induced _fusion_ is a lot dodgier. The proposal that I recall hearing about involved using antimatter-induced fission to heat a pellet of deuterium, D+T, or lithium deuteride. The problem is that you end up with what amounts to a miniature fusion-boosted fission bomb, which doesn't boost the yield that substantially over pure fission (it boosts it, but not to anywhere near pure-fusion numbers). Getting substantial amounts of fusion energy by this method gives you the same symmetry problems as with inertial confinement fusion.

The most practical approach to using smaller amounts of antimatter in spaceflight that I've heard of involved magnetically confining a plasma and injecting antimatter to heat it. This lets you make a system with higher thrust and lower Isp than a pure-antimater drive, which uses a lot less antimatter. However, it still ends up needing enough to be impractical. In fact, it's only actually useful when you're going for a better Isp than fission will give you, as in the gas core antimatter drive the reaction mass is dead weight, while in the fission drive it supplies some of the energy. While in principle you could kick-start a magnetic confinement fusion drive using antimatter, in practice I don't see the point, as it would still be as hard to build as a fusion drive that didn't use antimatter (Lawson criterion has to be satisfied to get power from the fusion).

In summary, lots of interesting ideas, but few viable proposals that I'm aware of. If you've heard of one that doesn't suffer these problems, by all means post about it.--Christopher Thomas 07:09, 13 January 2006 (UTC)

[edit] 100,000 vs 1,000,000 vs 10,000,000 m/s

I notice that the plasma velocity for a 10 kT nuclear weapon was changed from 100,000 m/s to 1,000,000 m/s. I also notice a very large jump in the 10 kT and 1 MT velocities. Can sources be cited for this? Back of the envelope estimates give numbers in the same ballpark (2000 km/s hard upper bound for fission, 16000 km/s hard upper bound for fusion), but this is only the case if no energy is lost as neutron radiation, and if the mass of the bomb casing, tamper, and so forth are neglected. In practice a realistic upper bound for fission would be about 200 km/s (as neutrons would carry away most of the decay energy), and for fusion it depends on whether you assume fast neutrons and tritium breeding are part of the fusion cycle, or whether D+⁶Li happens as a single step. For all of these reasons, I'd expect the real values to be much lower. For now, I'm changing the "1000,000 m/s" figure back to the "100,000" figure that was originally present, and leaving things otherwise the same, but citations for all of this would be really handy. --Christopher Thomas 21:24, 17 November 2005 (UTC)

It's a common mistake. The one million figure is a hypothetical upper limit for a long term Orion program. We could probably do a lot better today. Orion's perform most efficiently when built very large. The 100,000 figure is for one of the smaller versions. NASA was never interested in real Orions. They demanded a watered down miniature version for a Mars Mission. Got as far as a few schematics and flight calculations. The most popular article is this one which gives some good info.

The debris velocity for 10 kiloton pulse units is actualy in actual and literal fact about 1,000,000 m/sec. The explosion debris velocity for a 1 megaton pulse unit is in actual fact about 10,000,000 m/sec.The nuclear explosion debris velocity changes proportionate to the sqaure root of the amount of the magnitude of the change in the actual yield of the nuclear pulse unit.This results from the fact, that the actual temperature of the nuclear fire ball ,created by a nuclear explosion ,increase proportionate to the sqaure root of the magnitude of the change, in the actual amount of nuclear energy, that is actualy released by the nuclear explosion . Tim******************************************** http://www.islandone.org/Propulsion/ProjectOrion.html

Another good source is George Dysons fairly recent book "PROJECT ORION" which I ofcourse have on my shelf.

I'm puzzled by your statement that "we could probably do a lot better today", as the reasons for the figure being far below 16000 km/s haven't changed. The problem is that you need a lot of mass that isn't fusion fuel in order for the bomb to work properly. This is covered at nuclear weapon design. You furthermore have an unavoidable tradeoff between having a very thick casing and losing most of the neutron energy. Making the tamper and cladding out of fissile material only gets you to fission exhaust velocities, so it isn't much help.

The link you cited is a very nice overview of the project. I've added it to the links section. --Christopher Thomas 01:56, 9 December 2005 (UTC)

[edit] Number of deaths per launch

I've added a link to an article I wrote some years back for Space Daily. Hope that's ok. I could have added other links but I'm somewhat biasedly in favour of my own work over others. I expect most people are. Wolfkeeper might be interested in knowing that the 10 deaths per launch is based on the Non-Linear Threshold hypothesis and most radiation experts would greet such antiquated and false calculation with the derision it deserves. The radiation hormesis model is a far more accurate method of working out residual fallout risk. A friend of mine redid Freeman's dodgy calculation and came up with the figure of one possible death. Since this was based on 60's tech a modern launch would result in zero deaths.

Not zero. Might be a fraction of a person, but radiation-free nuclear bombs do not exist. Still, after a few thousand launches it adds up.WolfKeeper 05:14, 8 December 2005 (UTC)

Thus destroying your argument completely. Sorry. By the way, over a million people die every year as a result of cars.

But most people drive, or benefit from cars or vehicles. Very few would benefit from launch vehicles. And many would be terrified of radiation. It wouldn't fly politically. And it doesn't fly from a treaty point of view either- at the very least it would need testing with real nuclear bombs to make it work. fagetaboutit WolfKeeper 05:14, 8 December 2005 (UTC)

A pulse engine that has the support of the general public despite this massive carnage. I suppose you will be out on the street demonstrating cars now? Lol.

There's nothing to demonstrate against. At the end of the day, potential problems like spalling of the pusher plate may well be insuperable. Nobody has ever tried to subject something to hundreds of nuclear blasts. Even put-put only had 4 non nuclear. WolfKeeper 05:14, 8 December 2005 (UTC)

Ok Wolfkeeper,

A fraction of a person? Go and look up the theory you are so steadfastly supporting. That'll clear things up. Let me provide an example. The Non-Linear theory if applied to 'heat' would work something like this. If 200 degrees temperature kills a human body then by your reasoning 20 degrees will kill 10 percent of your body. Clearly this is nonsense. LT has been disproved.

Radiation free bombs are not necessary. You are getting more radiation from your computer monitor right now than you would from a remote Orion ground launch. Plane and rocket exhausts are radioactive as is the human body which produces it in the form of potassium. The rocks under your feet and the sunlight hitting your face are radioactive. It's pretty hard to escape. Uranium and Thorium exist in coal beds and thousands of tons gets burned at each plant annually. Multiply that by the number of coal burning plants worldwide and your arguments become silly.

People wouldn't benefit from a cheap super heavy launch system? You must be kidding. I hope you aren't arguing purely for the sake of saving face here. I'm sorry. Allow me to elaborate. Ordinary people colonising space. Mining the asteroids for countless trillions of dollars worth of exotic ores including platinum, berrylium and gold. One asteroid could produce over 100,000 tons of iron ore. That's greater than the annual output of China. Energy, zero-G metallurgy leading to new alloys, medical research, tv rights to planetary exploration, space telescopes looking for earth-like planets. Ordinary people don't benefit from 500 million dollar a flight shuttles for the military elite but Orion is different. Orion opens the door to space conquest. It can put bases on other worlds and habitats in deep space. Right now we have no presence in space unless you think of orbiting the earth as space. I don't. It's just skimming the atmosphere.

Yes, people are irrationally scared of radiation. They used to believe the earth was flat. If we had kept listening to people like you then we'd still believe it.

Putt-putt fired 6 TNT charges. Not 4.

Flying fox.

Nit-pick correction time:

• Your computer monitor is emitting negligeable amounts of ionizing radiation. You're thinking of very old television and CRT sets, which had a tube voltage high enough to produce x-rays that would penetrate the glass.
• The human body does not _produce_ radioactive potassium. It incorporates potassium (and other minerals) from food, and cycles them out eventually just like any other nutrient. I believe what you're referring to is the fact that of the naturally occurring radioisotopes, potassium is the one that's the largest contributor to naturally occurring radioactivity within the human body.
• The rocks under your feet are radioactive, but generally only if they're granite. In areas with granite rock there's enough trace thorium around to give problems with radon accumulating in enclosed areas with stone construction (like concrete basements).
• Sunlight is not "radioactive". Its only significant ionizing radiation component is UV. You're probably thinking of cosmic rays, some of which come from the sun.
• You are correct about fossil fuels dispersing considerable amounts of trace radioisotopes into the atmosphere. However, high-Isp rocket fuels tend to not be based on fossil fuels (though LOX/hydrocarbon rockets are popular for lower-stage boosters).

The _sane_ way of looking at this concern is to ask, "how many people will receive radiation doses substantially above background levels due to Orion launches, and in the event of a launch failure", and perform a risk analysis based on that. You can find further information at ionizing radiation (which covers linear vs. nonlinear models) and at radiation poisoning (for acute effects).

Regarding your points extolling the virtues of space exploration, I believe you are overlooking several facts:

• We're sitting on top of the biggest ball of metal we could ever want. We don't lack ores. The cost of transport and of space-based smelting facilities makes the economics of asteroid mining for a market that's on Earth extremely questionable, even if you assume that development of the Orion craft and asteroid tug technologies are free. For a space-based market, you have the chicken-and-egg problem (no such market presently exists).
• Despite claims of manufacturing benefits since the 1960s or earlier, nobody's been able to make a good enough business case to actually send a plant up there. The mass required for a technology demonstration is low enough that launch cost would be far less than technology development cost (it's about $10 million US per ton). We don't have much trouble making exotic alloys on Earth.
• Space telescopes are likewise expensive enough to produce that launch costs aren't the dominant expense. Building a high-quality telescope is _hard_.
• We've had camera drones light enough to send to other worlds for decades. The Mars rovers are the best examples of this type of technology, and paper designs have been around for years for rovers that are far lighter. Nobody's been able to make a good enough business case for commercializing rovers for remote-viewing for any company to build them, despite a relatively low cost of launch (a Hall-thruster transfer craft is light and uses off-the-shelf parts).

In summary, I find your arguments for vast economic returns from space exploration suspect. They've been made time and again for several decades, but no organization has seen fit to actually implement them. Private industry would have jumped at the chance long ago if the returns could be unequivocally demonstrated.

Lastly, I have frankly not been impressed by either your edits to Project Orion or your linked article. When paper deadlines in the real world have passed, I'll make an editing pass to bring the article back in line with style guidelines and to make sure that all content is factually correct, but for now, I'll settle for asking you to keep an encyclopedic tone, to cite your sources, to fill in your edit summaries, and to otherwise try to preserve the quality of this and other articles when editing them. --Christopher Thomas 01:40, 9 December 2005 (UTC)

Hi Chris, That was some remarkable nitpicking. I'm surprised you didn't start up on my spelling which being Australian doesn't always match english and american standards. Now I hope my solar powered laptop lasts long enough to nitpick your nitpicking.

Wikipedia:Manual of Style, which I referred you to already, covers this under the section "National styles of English" (as long as spelling is uniform within an article, changing it isn't needed). The main reason I pointed you there, and am still pointing you there, is because your writing style is neither WP:NPOV nor as encyclopedic as it should be. Your edits are very verbose and read like a pro-Orion screed. Specifically, statements like Orion creating "a golden age of space travel" and not being obsoleted "in the forseeable future" are both editorializing and poorly supported by the references given in the article. Wikipedia is an _encyclopedia_. It's supposed to contain dry, neutral descriptions of topics, with article contents reflecting the facts stated in the primary sources cited (Wikipedia itself is a "secondary source", summarizing information from elsewhere but not publishing new material). Editorialize or evangelize elsewhere - per Wikipedia:Neutral point of view, the content of the article should reasonably accurately reflect the published views of most experts in the field. Dissenting views (like statements that fallout would be minimal or that health effects from low-level radiation exposure would be minimal) that have been published can certainly be mentioned, but cannot be presented as the view of the majority of experts unless you can document that they _are_.

• Yes, monitors emit negligible amounts of radiation. That was the whole point.

• Granite schmamit. Radon from the ground is the greatest source of background radiation.

• Sunlight IS radiation. Both cosmic radiation and solar radiation is radiation. If you don't think light is hazardous then ask an astronaut about solar flares.

• It has nothing to do with fossil fuels. Practically all energy systems create radiation. With rockets you get the bonus of myriad other toxic nasties to boot.

• QUOTE "how many people will receive radiation doses substantially above background levels due to Orion launches, and in the event of a launch failure". Actually no. That would be insane. In parts of India the background level is as much as 100 times higher than other places like the US. Dosage is dependant upon proximity to the detonation so launching from Nevada would be extremely stupid.

• Monitors emit negligeable radiation compared to ambient background. If you're citing examples, make them relevant ones. I fully understood your original intent - I am trying to point out to you that if your examples are nonsensical, your arguments will be poorly received.
• Radon comes from thorium-bearing minerals. The concentration varies with mineral type. Granite is well-known for being the most problematic in terms of having both a high concentration and being relatively common (your basement isn't going to be lined with thorite or monazite). Go and read Radon#Occurrence if you don't want to take my word for it.
• Sunlight is radiation. Sunlight is not, as you had first stated, radioactive. Furthermore, you aren't going to get radiation poisoning from radio waves (though they may cook you) - it's ionizing radiation that's the problem. Hence, my correction (solar UV is the component to be worried about, and it's a whole lot less penetrating than beta, gamma, or neutron radiation).
• Fossil fuels are the primary power-related source of dispersed radiation. You're not going to get much radiation from a hydroelectric plant, are you? As for rocket fuel, high-Isp chemical rockets burn either hydrogen and oxygen, or fun things like nitric acid and hydrazine. In these cases, the chemicals are produced by processing air and water - not places you find uranium and thorium, compared to ground concentrations. Therefore most radionuclide dispersion will be from things like LOX/kerosene rockets, where contaminants from petroleum refining can stay in the product.
• Far from "insane", that's the only _sane_ way to do a risk analysis. The background level chosen as the baseline is that in the areas affected by the launch. While the health risk of raising radiation exposure by a modest amount is disputed, people whose radiation exposure _isn't_ raised substantially compared to the background they are already receiving are provably _not_ affected, and so have no grounds to sue. Realistically, the launch site and flight path would be chosen so that _no_ people had radiation exposure substantially above their background level, as getting experts to agree on what safe levels are is not presently possible (thus, there is no way to shield from liability). The accident scenario is just as important as the standard-operations scenario, as accidents _will_ eventually happen. Having them bankrupt the space consortium is not conducive to future launches.

Space.

• We lack many ores on earth. Being a big ball, most of the heavy stuff sank to the core long ago. That's why things like Gold are rare buddy. Actually, bringing stuff down isn't all that hard. Don't compare launching something to dropping something at 22km per second into a shallow sea. Mind you, my preference would be to use such resources in space. Makes more sense than ferrying everything up there with Orions. This way only a few launches are necessary. Maybe even just one.

• Conventional rockets couldn't even lift a plant into deep space. Metals of different masses don't mix readily. The heavier stuff sinks in the furnace. Out in space I could make you a mixture of Oil and Water. Only an Orion could lift the industrial infrastructure and workers necessary for such a huge project.

• Building high quality reflector telescopes in zero G is easy.

• Rovers are a joke. They belong at 'Toys R Us'. Not in space. Despite the huge public interest in the last few missions it was Mars the public were eager to see. What would sell is pictures of people on Mars. With Orion that becomes a practical proposition. Hell, we could send hundreds.

• Without nuclear energy we can't reach deep space with manned vehicles. Even exploration is hard. Until nuclear bombs become accessible to the private sector you will never see space mining and that's why it has never been demonstrated.

• We have all the ores we could ever want on Earth. We merely have to be willing to pay to refine them. This is in fact easier on Earth, because geological processes have concentrated desired elements in easy-to-mine mineral deposits. Asteroids aren't going to have veins of gold. Terrestrial quartz deposits do.

• To transport your metal-rich asteroids, you have to use either a very large ion drive or an Orion-style drive. Both cost a lot of money to build, and have to be maintained. Additionally, fusion bombs aren't free. You are going to have to make this ore acquisition process cost-competitive with digging the ore out of a hole in the ground. I have yet to see a reasonable business plan for doing this.

• Demonstration facilities can easily be lifted. I recall a study about doing integrated circuit wafer fabrication in space, for example, with the idea being that the wafers are relatively cheap to transport (being small but valuable), and with space vacuum leeward of the craft being much higher quality than you get in earth-based vacuum facilities. Lift a demonstration facility to prove the concept you're interested in, or send yet another experiment up in the Space Shuttle's research lab, and businesses would be able to make a stronger case for a cheap heavy-lift craft. Despite the studies and experiments being done, an Orion lobby hasn't happened. In practice, if you want to make a lead/aluminum alloy, you do it by using a levitating induction furnace (it's actually quite clever how these are put together). If you want to mix oil and water, you use a surfactant. The reason space industry hasn't materialized is that earth-based alternatives have been cheaper, even with the options of lobbying for Orion or building a moonbase on the table.

• Building high-quality reflector telescopes in zero-g is a royal pain in the tail. _Using_ them is easier, if you can get them there, because the support truss doesn't warp as much when you realign the mirrors, but space-based manufacturing has all of the problems of terrestrial manufacturing with the added hassle of having to develop new techniques and technologies to cope with zero-g and the need for a closed-loop plant environment. Adaptive optics are needed for a telescope above a given size no matter where you build it, so there isn't much of a complexity advantage to building in space. The main reason space-based telescopes are attractive has little to do with building them, and a lot to do with the fact that we're under a thick and constantly-warping blanket of light-absorbing gases.

• I think we're about as likely to make money from seeing celebrities on Mars as we are to make money from holding a concert in Antarctica. Ditto sending tourists (the moon is just as exotic and much cheaper to get to). If a business case for seeing noteworthy people on other planets could be made, the Apollo program wouldn't have ended. It was great for prestige, but didn't make much money.

• With ion drives, Hall effect thrusters, or other electric drives, you can go anywhere, if you're patient. With a nuclear-electric drive, you can get anywhere in the solar system in a timeframe that allows human crew. As a nuclear-electric drive can be scaled down much more easily than Orion, it's a much cheaper option, while still fulfilling exploration and prestige goals.

• If a business case could have been made at the time Orion was active for towing an asteroid to Earth to mine, either the US or the Russians would likely have done it. Even now, an ion craft could move a small rock. You just have to be willing to lift 0.1% of the rock's mass in engine and solar panels as your initial investment. Breakeven for this is about $10/kg for whatever you're hauling back. Use a concentrator or thin-film cells, and it's $1/kg. But, nobody's proposing a trip to do this.

• QUOTE "Lastly, I have frankly not been impressed by either your edits to Project Orion or your linked article.

Pardon me for breathing.

)

Flying fox (Wayne Smith)

My main complaints relate to Wikipedia:Neutral point of view, and secondarily to Wikipedia:Cite your sources (for claims mentioned in my first paragraph above) and Wikipedia:Manual of Style. If you are unclear on what the expected standards for article tone and content are, these and related documents will help you. Also, as mentioned previously, please fill in the "Edit summary" box below the edit window to indicate the nature of the changes you are making with each edit. --Christopher Thomas 07:03, 9 December 2005 (UTC)

I answered the above comments and you've seen fit to delete them. Very well. I have no time for dickheads like you Chris. If you don't like being corrected and shown up as an idiot then you shouldn't be editing. I've wasted enough time correcting your stupid comments.

Flying fox.

Excuse me?

1. I have deleted no comments of yours. See http://en.wikipedia.org/w/index.php?title=Talk:Project_Orion&action=history for details, and click on "compare selected versions" to see what was changed with each edit.
2. I have not removed any of your Project Orion material. My last edit was on 9 Dec. 2005 (diff), adding a link to the "external links" section. Check http://en.wikipedia.org/w/index.php?title=Project_Orion&action=history to see what was edited, and when.
3. You have committed vandalism by blanking my user page and replacing it with an insult (diff). If you want to remain on Wikipedia, don't do that.

In short, check your facts before making accusations (and before editing articles, for that matter). --Christopher Thomas 23:34, 16 December 2005 (UTC)

From reading the debate, it sounds like the topic has waned more towards whether or not Orion is a good idea based on its likely radioactive emissions, rather than what the number of deaths would be. It would be simple to resolve this and say that Freeman's estimate was ten, but much controversy exists on whether this would be higher or lower. Most of the controversy involves the difficulty in predicting fallout and its effects. —Preceding unsigned comment added by 71.37.18.74 (talk • contribs) on 20:24, 12 January 2006

Dear me, here we go again. For all interested, FlyingFox, Aka Wayne Smith, has a long and checkered track-record of pushing the Orion concept, to the point of flooding, spamming, ranting, insulting, spoofing other people's usernames and IP addresses, creating sock-puppets to support his POV, and in one case even hacking into and crashing a message board. While he may or may not have some reasonably good opinions as to Orion, his comportment and methods are highly suspect. Note to FlyingFox: if you are at the stage (and you were six years ago) where you find this kind of behavior acceptable, then there is something seriously wrong with you. Wikipedia is, as mentioned, supposed to be an informational site for reference and research, not your own personal rant-page. —The preceding unsigned comment was added by 68.163.177.5 (talk • contribs) on 13:24, 2 May 2006.

He was blocked indefinitely as of December 2005 for vandalism, so I doubt that messages to him at this stage will accomplish much. --Christopher Thomas 23:20, 2 May 2006 (UTC)

---

Few words about the topic. As far as I understood, the major problem is -- Linear no threshold model or Radiation hormesis model. Actually, what you need is a picture. I saw such one -- an "experimental" function, how the number of genetical changes depends on radiation level. As you go along x axis, at first there is a linear rise, then a "shelf" (with high dispersion), then parabolic rise. Or: at first the organism doesn't notice anything, then -- "shelf" -- special ferments start to repair damaged threads of DNAs, then -- parabolic rise -- damages are so often that the organism is unable to cure itself.

If this would help, I could bring the plot here. ellol 01:00, 16 August 2006 (UTC)

[edit] International test ban treaty

The ITBT parts of the article seem extremely biased. Even if what is said is technacally true, I'm sure that more scientific terms could be utilized. -Whursey 07:41, 27 December 2005 (UTC)

I have three question: Does the International Test Ban Treaty forbide the detonation of nuclear weapons or the detonation of nuclear devices or bombs in space? and Is the dynamite used in a gold mine a weapon or a tool?

Could it not be that a nuclear explosive detonated for moving an spaceship is not a weapon but a tool, like dinamite, or a propelant, like gasoline or gunpowder? 19:07 10 of September (Greenwich Time)

• The PTBT prohibits "nuclear weapon test explosion, or any other nuclear explosion" in outer space, yes. It does not practically diffentiate between explosions labeled as "weapons" and those labeled as "peaceful" because such would create an obviously huge loophole and make the entire treaty pointless. --Fastfission 23:09, 16 October 2006 (UTC)

I think it's completely stupid, what harm is a little radiation in space going to do to us. I can see them not wanting the bombs to be exploded on or near Earth but thats what we have chemical rockets for. Jay360 (talk) 20:38, 16 March 2008 (UTC)

Dyson was involved with the test ban treaty negotiations and writes about the tradeoffs. Read "Disturbing the Universe" for details.

[edit] External links

I've removed links to a discussion forum. IRC wikipedia rules preclude this.WolfKeeper 10:14, 16 March 2006 (UTC)

Can you provide a link to where it says messageboards are not allowed. Quarkstorm 19:54, 16 March 2006 (UTC)

[edit] pure fusion nuke

clearly i meant this and not "fision" in my edit summary. damn i and u keys are next to eachother. Give Peace A Chance 05:06, 20 May 2006 (UTC)

[edit] Plumbob Shot

Operation PLUMBOB was a *series* of nuclear tests conducted during 1957. The "orbital shaft cover" story has never been verified and may be an urban legend.

As far as I'm aware a shaft cover was blasted off the shaft with tremendous velocity, conservatively estimated as twice the escape velocity. This was it's speed as it left the earth's surface, of course it never made it into space as it would have burnt up in the lower atmosphere. So the story is at least partly true. I believe the scientist on charge of the blast gets somewhat frustrated at always being asked about the manhole cover. Quarkstorm 19:01, 28 June 2006 (UTC)

Isn't a plumbob that little diamond thingy from The Sims? FLaRN (talk) 02:28, 2 September 2006 (UTC)

[edit] Name being recycled

NASA announced that its return to the moon plans will fall under the auspices of Project Orion. Eventually, I predict that the old Project Orion will need to yeild and find a new page, as the new one will become more relevant to readers. Info can be found here. Give Peace A Chance 05:38, 22 July 2006 (UTC)

I concur. I have never created an article, but unless someone creates one soon I may create a new article to hold text about the new Project Orion. I assume that the names can be switched later fairly easily? Any comments on naming? --David Battle 02:00, 22 July 2006 (UTC)

Easily enough; it's done via the "move" tab. I'd suggest moving the current page to "Project Orion (nuclear spacecraft)", and put a disambiguation link at the top of the new article when it exists. My name suggestion is pretty ugly, but the problem is that both refer to spacecraft/space exploration projects. --Christopher Thomas 03:00, 22 July 2006 (UTC)

How about "Project Orion (propulsion project)" or if you don't like project being used twice, "Project Orion (propulsion study)" or simply "Project Orion (historical)"? Emax0 04:54, 22 July 2006 (UTC)

There is already a redirect page called Project Orion (spacecraft propulsion) which seems good to me. I'm going to take the dive and do the move, please be a second set of eyes for me since this is the first time I'm doing a move (I read the directions!). Emax0 05:06, 22 July 2006 (UTC)

OK I give up, lol, let an admin handle this. Can't reuse the existing name. Emax0 05:17, 22 July 2006 (UTC)

Actually there are several redirects. However since this is a logical dab redirect I'll make it happen and create the dab page. Vegaswikian 05:27, 22 July 2006 (UTC)

On second thought since this is a new nomination I'm going to opt to wait for additional input. Vegaswikian 05:30, 22 July 2006 (UTC)

• Since there are three uses, this page should become a dab page. There is no way to know that the current use of this name by NASA will be the last or the most important or that it will remain attached to the project thought its entire life. Moving the article is not an issue, but maybe Project Orion (propulsion) would be shorter. Vegaswikian 05:25, 22 July 2006 (UTC)

Well, if this becomes as big as Project Apollo as is the plan, then I don't think we can justify this as being a dab page. I imagine that in addition to dab links at the top, a section of the article will cover previous uses of the name.

I think Project Orion (propulsion) may still be too ambiguous for lay readers. Sending spacecraft to the moon involves propulsion, too, and it just might not be clear enough for some. I propose Project Orion (nuclear propulsion) for the current page and Project Orion (lunar program) for NASA's new project. Give Peace A Chance 05:38, 22 July 2006 (UTC)

OK, Project Orion (nuclear propulsion) does sound better but I still think that the main article should be about the lunar program. There are so many things tied into this, from the retirement schedule of the Space Shuttle (and thus the schedule of the ISS), to the new rockets being developed and the CEV (plus all the infrastructure changes at KSC and elsewhere), that even if the program is a total flop it still be have the greatest historical significance for the Project Orion name association simply based on the amount of resources and potential for historical impact. Emax0 05:56, 22 July 2006 (UTC)

• I've done the move, we can continue working on the dab issue. Emax0 17:44, 22 July 2006 (UTC)

Have just undone it and created a dab page at Project Orion. There's no justification for giving a stub the main billing. If/when any of the proposed moon progamme starts to happen we can come back and look at this again. Mtpt 17:46, 22 July 2006 (UTC)

Project Orion is not the name of a new NASA project as stated on NASA's Site, it is the name of the Crew Exploration Vehicle. Both the orion CEV page and the project to go to the moon Project Constellation have extensive wikipedia pages correctly named. 19:53, 24 August 2006 (UTC)

[edit] Momentum increases or decreases???

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.

It fails from physical point of view. May be the momentum decreases? ellol 22:20, 15 August 2006 (UTC)

[edit] How much would it cost

So it seems like there is no reason why Orion isn't viable right now. How many billions would it take to finish the engineering and build one?

There are still a number of somewhat dubious technical issues with Orion (e.g. dealing with bombs failing to explode, accurately positioning the bomb to control attitude, ensuring that the bombs are put into position fast enough without anything failing in the ejection mechanism), and in the current anti-nuclear climate it's a political non-starter. Mark Grant 15:33, 28 August 2006 (UTC)

Additionally it would also involve extensive nuclear detonations and nuclear testing which would have potentially quite different international political consequences. Even though the US has not ratified the CTBT it effectively abides by it, and something like this would be an obvious violation of the CTBT. --Fastfission 23:11, 16 October 2006 (UTC)

Orion would cost a lot less than our current plans for trips to the moon. It politics thats stopping it from being built. Jay360 (talk) 20:47, 16 March 2008 (UTC)

[edit] Weight and efficiency

In the Nuclear power section, it is stated that :

because of the force involved in the thermonuclear detonations and the need to absorb the energy without harm, large, massive vessel designs were actually more efficient

I'm not sure, but I believe this efficiency criteria is the ratio payload / dry mass or payload / initial mass, increased due to relatively lighter absorption device.

However, I think this should be explained, or else instead of being counter-intuitive, this aspect would stay counter-understandable. Duckysmokton 15:24, 28 August 2006 (UTC)

If I remember correctly, the larger the pusher plate, the more efficient, because it captures more of the blast wave from the bomb. That paragraph could do with a rewrite though. Mark Grant 15:29, 28 August 2006 (UTC)

[edit] Helios

The Helios link at the beginning links to the mythological deity rather than the propulsion system (which doesn't actually have a page at the moment). Given my lack of technical ability, I'm unsure how to correct this. The Dark 14:04, 1 September 2006 (UTC)

The disambiguation page for "Helios" references Helios (propulsion system) for this. That article doesn't exist, but I've changed the link in this article to point to it anyways. --Christopher Thomas 15:25, 1 September 2006 (UTC)

[edit] dates

nuclear pulse propulsion says Ulam proposed it ten years later 83.29.209.148 19:50, 3 December 2006 (UTC)

[edit] References in Fiction

I believe this concept was also used in Stephen Baxter's "Manifold: Space". Can someone confirm?

[edit] Question

Has a chemical version of this style of propulsion ever been developed? (except for the models to test orion)

If so what were the problems with it —Preceding unsigned comment added by 195.229.236.250 (talk) 16:55, 8 October 2007 (UTC)

Off the top of my head -- There wouldn't be much point to it. The idea is that nuclear propulsion can give a much more powerful thrust than chemical, but is difficult to engineer: Orion is a relatively easy "low-tech" nuclear propulsion system. Conventional "continuous thrust during operation" chemical rockets are more efficient than an intermittent thrust chemical rocket would be.

(If we could build one, we'd prefer a continuous-thrust nuclear rocket over Orion, as well.) (See Fusion rocket, Rocket_engine#Nuclear_heating, Nuclear propulsion) -- 201.19.77.39 05:12, 12 October 2007 (UTC)

Amplifying these comments, an Orion uses EXTERNAL pulses of energy. This is necessitated by the nature of an atomic bomb. Using teensy a-bombs INTERNALLY, like the HELIOS design results in poor performance and efficiency.

The problem is (other than the whole issue of Orion being illegal and a justification for creating new a-bomb designs and building 1,000s of bombs) that external detonations are extremely inefficient. A major design issue was creating bombs that focussed their energy in the proper direction. Some applicable weapon's designs apparently achieved collimation of around 85%. On the other hand, chemical combustion or various other nuclear propulsion designs lent themselves to efficient internal containment. That being said, ground launch Orions used a chemical blast at the begining to raise the ship a bit in order to lessen fallout and to increase the effectiveness of the a-bomb explosion. Yale s 14:52, 12 October 2007 (UTC)

[edit] Questions about speed vs number of bombs

At one point the article says that each explosion might add 30 mph to the speed of the ship. That seems very inconsistent with the number of bombs and the tremendous speeds the designs are supposed to be capable of reaching. If there are 1,000 bombs and each adds 30 mph, wouldn't the top speed be only 30,000 mph?

Now, maybe gravity is at play at that point. If there's a bomb per second, then it's losing about 30 mph more per burst to gravity. So, once it's out of the gravity well, the same propulsion could deliver 60 mph per blast. That's still not nearly enough to attain speeds like .01c. What am I missing? --Howdybob 09:06, 25 October 2007 (UTC)

Actually, I think 30mph was at takeoff, you need to use the rocket equation to more accurately calculate the final speed. Towards the last few bombs the vehicle mass would have gone down by a factor of say, 2 and then you would get 60 mph off each bomb. The loss of speed due to gravity depends on how quickly you detonate the bombs; it's a loss of roughly 22 miles per hour per second but it depends on the angle you are firing at and many other things, and they were planning on using two bombs per second anyway.WolfKeeper 14:06, 25 October 2007 (UTC)

Yeah yeah, my "30 mph/s" was off because I was thinking of 32 feet/s/s. Anyway, even if the ship loses half its mass, you're still not anywhere near 3-5% of C. Maybe the max speed figures were for different designs than the figures about the number of bombs? If so, I'd like to know the speeds of the actual proposed designs. --Howdybob 15:44, 25 October 2007 (UTC)

[edit] Slowing down

Just wondering, but how would Orion slow down and stop after attaining whatever its top speed would be? Would it have to have another pusher plate and detonate bombs in front of the craft? 131.61.211.15 (talk) 00:54, 18 January 2008 (UTC)

Well, now that I think about it, I guess you could just rotate the ship while its cruising. I wonder how much stress would be placed on the frame of a "Super" Orion by rotating it while cruising at .1 the speed of light. 131.61.211.15 (talk) 01:01, 18 January 2008 (UTC)

The ship has no idea that it is moving 1 mile per hour or 1000 miles per second. There is no important difference in the stresses involved in rotation at any velocity.Yale s (talk) 07:34, 18 January 2008 (UTC)