Talk:Project Orion (nuclear propulsion)/Archive 1

Archive 1

Archive 2

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

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)

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)

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)

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)

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)

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)

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)

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)

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)

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)

dates

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

References in Fiction

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

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)

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)

Archive 1

Archive 2

Citation request

Just for the record, most of the facts with "citation request" or "original research" warnings refer to facts quoted from the citations at the bottom of the page. The persons requesting citations could be more constructive by generating modern Wikipedia citations from Dyson's very interesting book, which has an excellent index and is available in many public libraries, or finding the research reports, which note, are cited with locator numbers and are also publicly available. Ray Van De Walker (talk) 23:09, 17 September 2008 (UTC)

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.

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)

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)

In it's own frame of reference the ship is stationary unless it's under thrust, it's the universe that's moving.
That said, the ship would almost certainly travel the majority of time in a 'reverse' orientation, much the same as the current space shuttles travel backwards while on orbit. Collision with interplanetary (or interstellar) dust particles would be the biggest single hazard, so travelling with the pusher plate as a shield would protect the craft from strikes. -Martin 220.253.165.90 (talk) 10:05, 27 August 2008 (UTC)

I think it gets worse -- using nuclear explosions is ok when you're traveling _away_ from them, but to use them to slow down you'd have to travel toward/through them. Unless you create some strange long parachute (??) that absorbs energy and can exert a force in the opposite direction, the project is toast for interplanetary "travel" (though it would probably make a terrific space probe). 132.239.215.15 (talk) 09:18, 25 April 2009 (UTC)

As long as you're outside the atmosphere, there's no difference between speeding up and slowing down. --Carnildo (talk) 10:43, 25 April 2009 (UTC)

Likewise, since the ship would have to be radiation shielded to travel through space safely, there's no worry about that; in any case, it doesn't matter which end the explosions happen on with respect to danger because relative to the ship the explosions would expand toward it at the same rate. Rifter0x0000 (talk) 19:45, 7 December 2009 (UTC)

Removed all fact and OR tags

All of these appear to have been added to people with little understanding of the subject matter and less understanding of mathematics. Don't fact and or tag a science-related article unless you can articulate intelligent criticism of what's posted on the talk page. Jtrainor (talk) 09:44, 11 October 2008 (UTC)

I agree. None of the statements in this article strike me, an interested and educated layman, as exceptional or in need of particular citations. The article is well-written with sufficient sources. It has been very stable so these aren't stray additions that need to be vetted. Two editors who are experts in the field have reviewed the article and found no serious issues. ·:· Will Beback ·:· 09:54, 11 October 2008 (UTC)

I added 2 fact tags before I read the above. I was requesting an inline citation to the source rather than doubting its truth. Since it's such a long article I think more inline citations would add to its value. Rod57 (talk) 20:10, 26 October 2008 (UTC)

How fast?

Im not sure if im missing something, but I havent found anything that states the speed of nuclear pulse propulsion (ie delta v) in this article or the nuclear pulse propulsion article. All ive found is stats for specific impulse and thrust, and that doesnt paint a clear picture of how it would perform. Bigdan201 (talk) 19:52, 27 February 2009 (UTC)

In general, "speed" isn't meaningful for spacecraft. The "top speed" of a spacecraft depends on where you're coming from, where you're going to, what path you're taking, what sort of propulsion you're using, how much reaction mass you're carrying (if you're using a system that needs it), how good your shielding is (at higher speeds), and in some cases (eg. Bussard ramjets) the density of the interplanetary/interstellar medium. Specific impulse is a measure of how fuel-efficient an engine is, and thrust is a measure of how powerful it is. These two combine with the propellant mass fraction of the spacecraft (a measure of how much fuel you're carrying) and the path taken to determine the available delta-v (the change in spacecraft velocity). --Carnildo (talk) 23:17, 27 February 2009 (UTC)

I see, thanks for the response. That explains why "speed" of a propulsion system cant be simply stated - there are way too many variables. However, I think a good statistic to add to the various propulsion articles would be - how long would it take to get to, say, Jupiter or Saturn from earth? And how long would it take to get from earth to Alpha Centauri? Since the two main questions of spaceflight are getting around the solar system and getting to nearby stars, that info would be helpful. Bigdan201 (talk) 06:41, 8 March 2009 (UTC)

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

The cancer death estimates were not based on 2010 medical knowledge, and would not be accurate today. —Preceding unsigned comment added by 207.5.148.229 (talk) 14:53, 27 February 2010 (UTC)

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?

Utter nonsense. I don't know where you get that an Orion is going to kill people every time it's launched. There are no people to die from fallout in space, and you don't have to use nuclear propulsion to get it off the ground. It is likely the ships would be built in space, anyway, for other reasons. Rifter0x0000 (talk) 19:07, 7 December 2009 (UTC)

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)

All this talk of "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" is very short sighted. If previous explorers had had that attitude we'd never have left Africa. Solving the problems of space exploration have direct applications here on Earth. Besides the new technology we've developed which has made life better on Earth in so many ways, the problems of pollution and environment management are likely to be better solved precisely because we are doing the research into those things necessary to do things like maintain life support for long trips and colonies.

As far as genetic diversity goes, cloning could be used instead of inbreeding, but in any case we could (and probably would have to) bring lots of genetic material in a very small space. DNA samples, which we might soon be able to amplify to the point of being able to inject into cells, take up very little mass and volume, and even sperm, egg cells, or embryos would be negligible in the context of a generation ship you imagine.

Now one thing that constrains us here is that it would be likely we would need, and it would probably be desirable, to bring other life forms which help support life as we know it on Earth, much as the Polynesian and European explorers did. We'd probably need to figure out ways to bring those things in a more compact package, like with the DNA material above.

Oh but all this work with DNA and cloning and the like again have direct impact on the Earth and its problems. For instance better ways of recording, amplifying, and reinserting DNA might help us preserve endangered species. It's probably a good idea for us to gather as much genetic material as possible anyway because you never know when a gene might come in useful and even prolific species (for instance the banana) can suffer catastrophic loss (in that case poor diversity was a contributing factor).

So, again, anything we work on to help projects like this is also useful for the problems we have on Earth. This is quite apart from the fact that we could have catastrophe on Earth that might wipe out life or make it less than habitable even if humans clean up their ways, which is a good argument for colonies elsewhere which might preserve life. Rifter0x0000 (talk) 19:35, 7 December 2009 (UTC)

Overall, project orion and nuclear propulsion in general have great potential for transportation through space. creating nuclear fallout on earth would not be good, that is why it would be more prudent to make a non-nuclear launch from earth, then fire up nuclear propulsion in space. hopefully research can continue . . . it seems that orion cancellation was a bad side-effect of nuclear containment. and whodoesntlovemonkeys, im not sure what youre talking about. your argument was all over the place. Bigdan201 (talk) 20:02, 27 February 2009 (UTC)

Wolfkeeper, how do you know that only the crew of a space shuttle will die if it explodes? What if fragments hit some vessel out at sea? They do have a restricted zone to limit the possibility of people being hit by falling boosters, but the risk is still there, or don't you think about it because launches are relatively commonplace? What about the effect on people with respiratory problems with burning chemical rockets, there's bound to be some nitrogen oxides produced by the thrust in the atmosphere, and this is just conventional rocketry. There are plenty of other pursuits we do, including using arsenide in semi conductors, which may kill people. Certainly burning coal in power stations is estimated to result in deaths of people through enduced asthma attacks and other respiratory issues. In fact, the environmental campaign against DDT has certainly resulted in thousands of deaths every year from malaria in many parts of the developing world. If we look at things we do, a statistical average of 1 to 10 extra deaths doesn't seem to be much of a deterent, either because it's counterbalanced by saving more lives that this, or because of some "higher good" (i.e. DDT ban).

Whodoesntlovemonkeys, I think you need to rethink your comment. The point about Orion is that it makes round trips, or multiple trips feasible. A Mars colony would not require cloning or any of these "sci fi" nonsence. You need a breeding population of 50 or more. Well Orion can actually take that number of people to Mars. There would also be several expeditions, and establish a population of hundreds, which would not "die out" from inbreeding. Nor with this necessarily be the end of the story. Put it this way, what was the point in colonising the "American Colonies" as the Pilgrams on the Mayflower were relatively few, and hence America should be dead from genetic inbreeding! You are right, however, on the question of building it on the Moon. You'd need an entire industrial facility up there, and that will take decades (particularly with programes being started and then cancelled). The most obvious way to get that sort of infrastructure up there would be to actually use an Orion to launch it from earth! Launching segments from Chemical rockets would be so expensive as to rule it out. The Saturn V could launch 45 metric tons to the moon, note this is to luna orbit NOT luna landing which would require much of this mass to be fuel for the decent. So even if the craft were assembled in one of the lagrangian points, you'd need 100 Saturn V launches to move the material from the Earth's surface for a 4,500 metric ton spacecraft! Also a crew would not need to spend 100 years on an Orion for use in the solar system. The point about Orion is that this technology would genuinally open up the solar system to human exploration and colonization, and to commercial use. All those O'Neill space colonies, so beloved of some conservationists, would require this technology literally to get off the ground. As for "not doing anything" until "we've solved our problems on earth", well there will always be problems, so we'll never go anywhere then. I'm sure plenty of people whined about the cost of satellites and how much better spent that money would have been on social programs etc. Do you think we're better off with weather satellites, communication satellites, landsat etc?

In actual fact, those involved with the project felt they could slowly refine the system to reduce the level of statistical deaths to the rate of 0.1 or less people per launch. The issue isn't so much the actual pollution released from such a launch (or landing) but the political ramifications, particularly given how the the general public is so absolutely hysterical at even the mention of the name "nuclear".

Orion is an example of a technolgical development we've walked away from. A good counter example to people who claim we "always move forwards", and that technology will develop in various ways whether we like it or not. Personally, I think it is a bad thing we walked away from this one. Whilst it isn't practical for intersteller human travel, it would certainly open the solar system to a wide range of human activity.

— Preceding unsigned comment added by 212.39.162.130 (talk) 16:17, 5 October 2010 (UTC)

Inertia Principle

To the best of my knowledge there hasn't been any research done to stop this turn it around and come back the other way. Which would mean that it would only be good as one way probe that will keep on going sending pictures back from where ever it goes. In fact I don't think anything that has ever left Earth's orbit has ever been intended to return regardless of what type of propulsion it uses. Outside of the moon landings and space stations everything has been automated. This article makes claims that are almost certainly not supported by known science. Yet anyway. For more on the inertia principle see Newton's laws of motion.

Zacherystaylor (talk) 04:52, 27 September 2008 (UTC)

If you want to accelerate in a particular direction, turn the ship to point that way, and KABAMM!

—WWoods (talk) 15:55, 27 September 2008 (UTC)

Perhaps but this is just theory for now and it would require extra power whenever changing direction or speed. I will ammend my previous statement about nothing returning I think there was one exception a automated satalite that orbited the sun before returning it collected small amounts of matter that was in space or something like that but it didn't land on a planet or go into the outer solar system. That would require more power. The story that was presented by the media seemed strange though can't remember the details.

Zacherystaylor (talk) 05:37, 29 September 2008 (UTC)

...you do realize that current space ships and satellites in existence, right now, use exactly this method to maneuver, right? Jtrainor (talk) 04:38, 10 October 2008 (UTC)

Zacherystaylor, to enter Luna orbit, the Apollo space craft fired it's Service Module engine in the direction of motion to slow the craft down. Nothing "theoretical" about that, it was done with every manned Apollo flight apart from Apollo 9 (LEO) and Apollo 13! It is done with the automated Luna orbiters, whatever country they're from. It's done with all craft that have orbited Mars, Venus, Jupiter and Saturn. There are no excess stresses in turning an unaccerating body in a vacume, other than the turning moment itself, no matter what the velocity (at least in non-relativistic velocities). So slowing down and coming back are not a problem. It is primarily a question of how much fuel you carry. The Orion system has the necessary power and efficiency to carry sufficient fuel for this.

As for slowing down, it would simply requiring turning the ship on its axis, which would not require much force, and then firing the "rockets" again. Obviously, any change in velocity requires work and it would take just as long to speed up as to slow down. As for returning, I don't see any reason why this technology could not power a return trip, if that were desired for some reason. Regarding the article as a whole, User:Fastfission, an expert, edited it back in 2006, and didn't report that there were still major errors (not that he was necessarily checking). The article has barely changed since then.[1] What particular problems do you see? ·:· Will Beback ·:· 07:18, 10 October 2008 (UTC)

For one thing the article is full of citation requests and concerns about original research. The Orion Project is mostly a propulsion research project. It doesn't adress the needs for long distance manned flight. It implies that a single mission could provide a permanent moon base which is probably false besides other technology could do that better. Carl Sagan said in Cosmos that it would have to be built in space to avoid polluting the Earths envirnment which is true even if it was launched in Antartica using nuclear power it would pollute the earth. Furthermore they are not prepared to launch anything from Antartica. I have read several artilces and books that mention Orion but no claims that it can go 50-80 % of the speed of light as the following Quote says: "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]" Project Longshot and Project Daedalus are much clearer articles without all the citation requests which didn't come from me. This Project is used by sci-fi buffs to claim that interstellar space travel is possible already in some cases but this is mostly theoretical. It has never been put through the final test. this could be made clearer in the article. When it comes to high speeds reversing direction would get much tougher. A trip to Mars might be as simple as you imply but the higher speeds neccisary to get to other systems would require more than the technology currently available from Orion. In order to slow down or speed back up after you reach 10% the speed of light would require much more power.

In general I just thought this article could use the attention of someone with more expertise in the subject. I don't claim to have that expertise but I've read enough to have a lot of doubts about the article and how it could be used by pseudoscientist etc. If an expert looked at this I'm guessing he would find even more problems with it than I do.

Zacherystaylor (talk) 09:02, 10 October 2008 (UTC)

Disclaimer - I'm an aerospace engineer as part of my work, and I'm familiar with space propulsion in general and nuclear weapons and their effects. I've made a hobby study of Project Orion.

The citation needed requests and {{fact}} tags and so forth are in fact mostly asking for information which is in the sources listed already, the reliable and in some cases quite good books about the program which have come out recently, and the origional now mostly declassified project reports about the designs.

I appreciate your concern, but the article as it stands is very accurate. Georgewilliamherbert (talk) 20:52, 10 October 2008 (UTC)

Additionally, Zacherystaylor, it takes the same amount of energy to stop as it did to accelerate to the current velocity, not "much more." This doesn't change regardless of speed. Rifter0x0000 (talk) 19:54, 7 December 2009 (UTC)

Thanks for looking at it. If I get the chance I'll read more on it and perhaps find sources to cite to remove tags but it probably won't be soon

Zacherystaylor (talk) 03:34, 11 October 2008 (UTC)

BTW, I looked at Project Longshot and Project Daedalus. Those articles are much shorter than this one, with fewer sources. Those are both more recent, and the information may not be available yet, or they may have been less thorough studies than this one. As noted, the Orion technology does not require any major discoveries, while both of the other projects depend on laser-triggered inertial confinement fusion, which is still being developed. They would also require phenomenal amounts of helium-3. The point being that those articles are clearer because they are shorter and simpler. This articles discussed more of the engineering and design challenges and in greater depth. ·:· Will Beback ·:· 10:17, 11 October 2008 (UTC)

Zacherystaylor, Carl Sagan did NOT say it would have to be built in space. He was a bit of an environmentalist, and a bit of an anti-nuclear activist, and so he wasn't happy about launching from the earth's surface from a political/philosophical standpoint. He only said there was no problem so long as it was launched far enough from the earth. Just one line, not the extensive comment you've attributed. Besides, how do you justify your assertion that a single mission could establish a luna base? The quoted figures for the "advanced interplanetary" quote 5700 tons to luna landing compared to 52 tons for the Saturn V (which is actually to luna vicinity, not landing). At least in theory, a single Orion launch could carry all the physical infrastructure needed for the base, and put it on the luna surface. I also can't see how you can assert that chemical rockets would "do it better"? Rocketry is all about lifting power, the more the lifting power the greater the payload, the more you can do. No rocketry system we have has the lifting power of the Orion concept, so Orion is easily the most powerful, and hence capable, rocketry system currently within the scope of our technology. Whilst the article is clearly written by people who are in raptures over the "lost opportunity" the fact that Orion could open the solar system to us should not be in dispute. — Preceding unsigned comment added by 212.39.162.130 (talk) 16:17, 5 October 2010 (UTC)

Will EMP Be a problem or not?

The 'Potential Problems' section states both:

• "The danger to electronic systems on the ground (from electromagnetic pulse) is insignificant from the sub-KiloTon blasts proposed."
• "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."

These seem to be completely opposed summaries of the effect of the electromagnetic pulse. Neither are cited, which is correct? Tom (talk) 18:31, 23 September 2009 (UTC)

Doing a little original research based on the good old Effects of Nuclear Weapons it seems that the maximum deposition region is, in any high-altitude case, around 40 mile altitude. Empirical results from tactical nuclear tests suggests that as far as surface bursts are concerned micro-nukes produce negligible EMP in that if you're close enough to worry about EMP, you've greater things to worry about. What I think this suggests is that as an Orion craft ascends it creates a greater and greater risk to satellites until it's far enough away that the inverse cube (?) law makes the result once again negligible compared to day-to-day variance. By this, it seems both statements are true: the danger to electronic systems on the ground is insignificant; but it could cause significant data to computers [on] satellites in orbit.

This is, of course, original research and inappropriate for inclusion in the article, but it gives us an idea what to look for in some future source. --The Centipede (talk) 21:49, 2 April 2010 (UTC)

Wrong Numbers ?

Under "Energy limited Orion" it is stated that the diameter is 20000m and the Mass 10 000 000 tons, that is only 33kg for a square meter. —Preceding unsigned comment added by 84.150.197.205 (talk) 11:10, 15 February 2010 (UTC)

Wrong Units!

In this version of the page the author has converted metric tons to US short tons. Bad! Very bad! Remember the Mars Climate Orbiter?

NASA is working with the metric unit system. NASA is asking its subcontractors to use metric system. All space agencies are metric. Anything about space space travel should be metric. Why screwing numbers which were expressed with the good unit in the first place? —Preceding unsigned comment added by 134.160.83.73 (talk) 04:32, 22 September 2010 (UTC)

What does the pushing?

The article fails to state what does the actual pushing of the spaceship. I mean, here on earth explosions have shock-waves due to the fact that we have atmosphere, and that could be harnessed by the pusher plate like wind and sail. In vacuum of space the only result of a nuclear explosion would be a bunch of photons, neutrons and trace amounts of matter from the bombs casing, no? How can the pusher plate turn this into kinetic energy? It should be stated in the article. Ma770 (talk) 09:12, 12 March 2010 (UTC)

It is the plasma wave of the volatilized materials of the bomb. Especially an inert mass of tungsten topping the unit, check this image for the conception of the pulse unit. Duckysmokton ^blabla 23:34, 14 March 2010 (UTC)

Speed again

I see a problem concerning top speed of the Orion. The 10% speed of light figure is present in Carl Sagan's "Cosmos" but he does not cite any sources for this himself...Nor does he explains from where did he get it...Maybe you should reconsider sourcing article with his book???

Also, I find strange conclusions concerning Dyson's calculation. He claims that 300.000 Mt of energy can make 100.000 tons of rest mass moving with the speed of 10.000 kilometers per second. The problem is that according to Einstein's theory the factor gamma that describes the relationship between rest mass of the body and the mass of the same body moving with certain velocity ($\gamma =1/{\sqrt {1-v^{2}/c^{2}}}$ that factor takes value ca. 1.0005 for v= 10.000km per sec. That implies, that the mass of 100.000 ton Orion measured from static frame of reference should amount to ca 100.050 tons...The additional 50 tons should be equal to energy used to speeding up the spaceship. But 1 kilogram of mass is equal to 21.4 Mt of energy....So 50 tons = 50.000 kilograms should require at least 1.050.000 Mt of energy....Yet Dyson writes that 300.000 bombs with 1 MT yield is enough....Could someone check it?

Here is a link to Dyson's article: regardless of feasibility of my remark, the link may be used to improve the article:

http://galileo.phys.virginia.edu/classes/109.jvn.spring00/nuc_rocket/Dyson.pdf —Preceding unsigned comment added by 193.25.0.13 (talk) 18:10, 16 April 2010 (UTC)

Important information- the info in chart is misleading...It suggests that Orion can achieve 10.000 km per second using 300.000 nukes each with one tonne mass and one megatonne yield...This is wrong. Dyson states in his article that one tonne-one megatonne construction is the lower limit while the upper is kinda "pure fusion" bomb with 100 Mt yield and one tonne mass (I am not sure whether such thing is even possible)..However the article seems to suggests, as far as I understand it -that to achieve 10.000 km per sec each one tonne bomb should have a yield ca 70 MT...So I suggest removing info from chart that each bomb has a yield of one Mt.... —Preceding unsigned comment added by 193.25.0.13 (talk) 23:21, 19 April 2010 (UTC)

I think the figure of 0.1 c should be removed from the article; it looks to me like Sagan just made it up. That whole chapter of Cosmos is pretty far divorced from reality.

The special relativistic rocket equation implies that the best achievable fuel-to-payload ratio for a rocket in vacuum is e^{Δα / β} − 1, where Δα is the total change of speed (0.2 for acceleration to 0.1 c and then back to 0) and β is the exhaust speed. This ratio is hopelessly large unless your exhaust speed is comparable to your maximum cruising speed. The high-speed designs walk a very fine line if they're sensible at all (which I somewhat doubt). -- BenRG (talk) 04:53, 10 May 2010 (UTC)

Wildly inconsistent claims of exhaust velocity

The lede says 10 to 1,000 km/s. It cites this article, but that article actually says "10,000 to one million seconds", i.e., 100 to 10,000 km/s (multiplying by g ≈ 10 m/s²). But it cites the declassified General Atomic report, which (on page 17) gives values in the range of around 1,000 to 4,000 s, i.e., 10–40 km/s. Meanwhile, the article body has numbers ranging from 20 to 30,000 km/s in various contexts. Can someone with a knowledge of the subject sort out this mess? -- BenRG (talk) 04:21, 10 May 2010 (UTC)

Ground nuclear tests

The Background part says that tests with steel spheres were during the Operation Castle in 1954. But some sources say it was Redwing Inca device in 1956 (for example, http://glasstone.blogspot.com/2006/04/ten-largest-nuclear-tests.html:"Dr Taylor says in The Curve of Binding Energy (by McPhee) that the idea stemmed from the 15.2 kt REDWING-INCA nuclear test on June 26, 1956, where 30 cm diameter carbon-coated steel balls were placed 9 metres from the bomb by researcher Lew Allen, and were undamaged with only a loss of 0.1 mm of surface graphite!"). There is a great differnce between 15 kt and 20 Mt. I've found no sources with information about both Castle and Redwing sphere tests. Can someone help with that? -- Xahtep (talk) 10:24, 18 January 2011 (UTC)

Mass of the "Super Orion" charges?

This table gives them an individual mass of 3000 tonnes, not 3 tonnes as the article states. —Preceding unsigned comment added by 174.118.10.147 (talk) 19:00, 16 February 2011 (UTC)

Multiple plates

An I.C.E. uses explosions, to generate thrust. But, by using multiple detonation chambers, cycled rhythmically, a smooth output thrust can be approximated. Could not, therefore, an Orion craft use multiple pusher plates, arranged in a circle, as a (if one would) "O-6" nuclear pulse engine?? Also, could not the pusher plates themselves be shaped, curved with concavity (like a standard rocket thruster cone), to 'catch' more of the blast?? And, 'active cooling' could be used, with 'veins' threaded through the pusher plate, through which coolant liquids would be continuously flushed, to extract the heat (a little like a water-cooled I.C.E.). And more, those heated liquids could be used to generate steam-turbine power (perhaps???). 24.143.65.75 (talk) 04:47, 18 May 2011 (UTC)

External links

The following link needs to be updated because Peoples Archive have now been moved to a new website called Web of Stories:

Freeman Dyson talking about Project Orion on Peoples Archive

The correct link to the Web of Stories website (http://www.webofstories.com) should be:

• Watch Freeman Dyson talk about Project Orion

193.201.196.10 (talk) 15:05, 4 July 2011 (UTC)

Contradictory EMP Paragraphs

One paragraph states that EMP would not be a problem because small nuclear devices do not result in EMPs. Later on in the same section there is a paragraph which states EMP would be a problem and discusses possible solutions. Something needs to change, but since neither seemed to have any sources, I couldn't verify which was right.76.27.123.7 (talk) 06:55, 24 October 2011 (UTC)

Interstellar missions

The payload and the crew capacity need to be added to the Interstellar missions chart. Keraunos (talk) 05:18, 26 July 2012 (UTC)

Use of US short tons

Shouldn't the values listed in the table in this section use kilograms instead of US short tons? Richard Munroe 17:54, 14 August 2012 (UTC) — Preceding unsigned comment added by Rimunroe (talk • contribs)

I agree. It makes no sense using the metric system for lenght/height, diameter etc and using the US short tons for weight. Either have 1 system for all measurements or use both in parentheses. — Preceding unsigned comment added by 37.6.49.247 (talk) 23:41, 23 September 2012 (UTC)

Broken links in Further Reading

All of the PDF links in the Further Reading section are broken. — Preceding unsigned comment added by 68.175.103.89 (talk) 00:59, 18 October 2012 (UTC)

Improving the article

The page could be substantially improved by including material taken from the French or German wikipedia pages on the project. Have a look below, and translate the page if you're rusty on French & German.

• http://de.wikipedia.org/wiki/Orion-Projekt

• http://fr.wikipedia.org/wiki/Projet_Orion

What do you think? They're much better articles, right? 86.41.232.78 (talk) 11:42, 20 July 2013 (UTC)

Errors in "Appearances in fiction" section?

This entry exists in the wiki page at present (without citation):

"The novel by Arthur C. Clarke, 2001: A Space Odyssey, included a ship "Discovery 1" using this drive. The vehicle in the movie did not use this idea since Stanley Kubrick was disillusioned with nuclear power after making Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb."

But looking at the Wiki on the Discovery One, this does not appear to be the case:

"powered by "Cavradyne" gaseous core nuclear reactor engines" - http://en.wikipedia.org/wiki/Discovery_One

Which is actually the engine described here: https://en.wikipedia.org/wiki/Gas_core_reactor_rocket

I'd do a direct edit, but it's been so long since I played with Wiki, and this is a potentially signifigant page, I didn't want to edit unilaterally.

Tensin (talk) 17:00, 22 July 2014 (UTC)

Wkiki Gnome type question about an unclear statement

This is just one of several questions I have about the writing style of this article. Please imagine that the target reader is a high school student who is learning pre-pre-engineering terminology. What does this statement mean? "The pusher plate's thickness would 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." How can it be re-written to be more clear to the general reader? Is the factor 6 a multiplicand? a log? a percentage? is it positive or negative? is the edge thicker or is the middle thicker? What is a differential velocity in parts of a solid object? Thanks! Trilobitealive (talk) 15:21, 25 October 2014 (UTC)

Credibility of citation 23

Is there any credibility to the claim that Coca-Cola was consulted on this design? It's an interesting factoid but it smells pretty fishy.

131.151.159.66 (talk) 21:54, 21 November 2014 (UTC)

Project: Orion Battleship Version

So, I was thinking: why has Wikipedia not added in the Battleship Orion version of the design? Based on some popular science fiction sites and on the book about Project Orion by George Dyson, there was a version that was designed as a battleship. Or is this incorrect? - Ace009, Alternate History Wiki — Preceding unsigned comment added by 24.48.194.85 (talk) 21:28, 29 September 2015 (UTC)

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ISP is incomplete

The page gives a formula for what the ISP of an Orion engine is and gives values for two of the three terms--but doesn't provide the slightest hint about the value of the third.Loren Pechtel (talk) 21:36, 15 May 2016 (UTC)

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