A diamond hull will not be enough!

mcbethcg · Sep 18, 2004

To take care of atomic sized particles, how about making the sheild out of iron? Make the ship extremly magnetic. As the shield is ablated, at least some of the blasted off particles might return to the poles, to be remanufactured into plates that could be returned to the sheild. For larger particles, the only thing that could prevent damage would be a free floating sheild a few thousand miles ahead, to convert incoming rocks or chunks of dust into atomic sized particles through collision.

a_lost_packet_ · Sep 18, 2004

maddad - what makes you think that there is a shred of experimental evidence?.. Get real. "Get real" ??? Just what is your problem? Why the rant? I posted a link to data pertinent to tests involving the Orion drive even though I am not a proponent of such a system. This was done in the interest of serving the discussion on the subject. Did you read any of it? Or, instead, was it more entertaining for you to just rant/flame? maddad - In the very same way the chemical explosive tests are about a thousand times colder than the nuclear bomb blasts that would drive Orion. Chemical explosives give you tens of thousands Kelvin; nuclear bomb blasts give you tens of millions Kelvin. You cannot experimentally test for the melting of steel on the Sun with liquid helium, and you cannot test for the ablating of the Orion pusher plate with chemical blasts. (Uh. Tens of millions Kelvin? Golly.) You are wrong. By inducing a plasma state in the helium, as the article suggested, you could reach the melting point of a steel alloy. You can also test for ablative effects by using chemical "blasts" if they are relative to the material in same degree as to the the kinetic effects your are testing for in a nuclear explosion. In other words, the degree of damage will be the same given similar amounts of energy. What do you think "nuclear" is? You treat it like some sort of unkown form of energy. Yes, a nuclear blast is nothing to scoff at. However, it is just energy. You can classify it into varying degrees of type. Most of the initial damage is kinetic. In the immediate vicinity, thermal damage due to interations of material with intense radiation occur. Absorbption of thermal energy by surrounding materials cause combustion. Interaction of intense gamma and x-ray radiation with matter produces <div class="Discussion_UserSignature"> I put on my robe and wizard hat... </div>

mcbethcg · Sep 18, 2004

Eloquent.

Maddad · Sep 20, 2004

mcbethcg "Where in the world did you get the 10 million number? How many seconds are there in a four month mission? 10 million, right? If you space your blasts one second apart then that's how many you'll need. You cannot run Orion with spacing much greater than one second intervals because it would give you a bumpy ride. The wider the spacing, the bumpier. "Additionally, while the core of a nuclear explosion may reach the temperatures you describe, the average temperature of the entire device is lower by several magnatudes. That's highly debatable, and <big>you still don't have a trace of experimental evidence.</big> "Then that expanding cloud hits the pusher plate after dispersing. . . if you knew a damn thing about physics, gases temperatures decline as presure decreases. Funny that you should mention physics. The problem isn't the expanding cloud; it's the radiant energy. If you knew a damn thing about experimental evidence . . . packet "I posted a link to data pertinent to tests involving the Orion drive . . . Dude! Read my lips. You posted a link to speculation, not pertinent tests. "Uh. Tens of millions Kelvin? Golly.) You are wrong. As much as 100 million Kelvin, but that's not the point. Ever hear of <big>experimental evidence</big>? Show me some and then tell me I'm wrong. "Did you read anything presented? Did you present a nuclear test of multiple exposures? <big>No!!</big> So you ain't presented nothin'!! You say that a nuc

a_lost_packet_ · Sep 20, 2004

maddad - mcbethcg "Where in the world did you get the 10 million number?" maddad - How many seconds are there in a four month mission? 10 million, right? If you space your blasts one second apart then that's how many you'll need. You cannot run Orion with spacing much greater than one second intervals because it would give you a bumpy ride. The wider the spacing, the bumpier. Perhaps you have not looked at the design of the craft? The majority of the undercarriage is designed as a giant shock absorber. It is designed to handle such a load. As far as the interval is concerned, I'll have to take a look at the proposals. However, there were tests conducted using a steel plate. The plate melted not because of the heat of the explosion, but from the friction of the atmosphere due to acceleration. The "bumpy ride" is not an issue and was accounted for in the design. mcbethcg(?)-Additionally, while the core of a nuclear explosion may reach the temperatures you describe, the average temperature of the entire device is lower by several magnatudes. maddad - That's highly debatable, and you still don't have a trace of experimental evidence. The "trace" of experimental evidence is included in the link that I provided in my above posts. A full bibliography is available at the bottom of that page. Every presentation of pertinent data mentioned is referrenced in the bibliography. You are capable of clicking on the link and looking at it for yourself. I shouldn't have to re-post it again should I? mcbethcg(?) - Then that expanding cloud hits the pusher plate after dispersing. . . if you knew a XXXX thing about physics, gases temperatures decline as presure decreases. maddad - Funny that you should me <div class="Discussion_UserSignature"> I put on my robe and wizard hat... </div>

silylene old · Sep 20, 2004

So, your opinion rests on "multiple nuclear blasts?" Well then, why? Explain your position. How would the results for tests of equal-distant spacing of multiple nuclear blasts against a theorized pusher-plate invalidate the results of the experimental test detailed and the subsequent opinions of the researchers involved with project Orion? Well, for one, what is the effect of neutron capture on the embrittelement of the pusher plate? It is very well known that fast neutrons impinging on metals induce point defects in the metal which rapidly causes embrittlement, and then catastrphic failure. Metal embrittlement increases with time, causing fatigue and failure. That's why the reactors of nuclear power plants have a limited lifetime. The neutron emission rate from a bomb is orders of magnitude more than a "soft" nuclear reactor, and the neutrons are "faster" and not mitigated by various damping materials typically used in a reactor. Hence the embrittlement rate of the exposed pusher plate will be faster. Also, the rate of embrittlement changes with temperature, and I don't think that models for the very hot temperatures the pusher plate would experience have even been studied. I would think the continual extreme jarring effect of impacts on the pusher plate (which, by design, must be on the high-impact side of the shock absorbers) would only exacerbate the fatigue on the pusher plate as it becomes embrittled. There are dozens of excellent links on embrittlement of steel and other alloys on the web, and many books and thousands of refereed scientific papers on this subject. I am simply suggesting that this is one of the many engineering "details" that can rapidly become a fatal flaw with no known alternative. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center">- - - - - - - - - - - - - - - - - - - - - - </div><div class="Discussion_UserSignature" align="center">I really, really, really miss the "first unread post" function. </div> </div>

Maddad · Sep 20, 2004

packet "there were tests conducted using a steel plate. No dude! There were no test conducted because there have never been a series of nuclear blasts testing the survivability of a material. I like the word pertinent that you used above. Orion proposes a nuclear propulsion system. If you only give it a chemical test, then <big>you have no experimental evidence</big>. "Will you choose to ignore all data unless it conforms to the "multiple exposure" rule? I am glad that you finally have a firm grasp of the obvious. Orion proposes multiple nuclear exposures. If you do not have experimental evidence involving multiple nuclear exposures, then you have nothing for anyone to look at and your tin hat fantasy dies right there. Now, if you have any links at all to a closely spaced series of nuclear blasts, then give me the link. Otherwise you're just flapping your gums like a SETI forum lunatic.

a_lost_packet_ · Sep 20, 2004

Silylene - Thank you for your informative reply! This is exactly the type of question that should be raised when considering the issue! Maddad - take a look at Silylene's post. That is how you should post when presenting an argument for your idea. Shouting in green text is not how you should present an argument to support your position in this forum. Silylene - I do not have a counter at this time for your suggestion. I have to stress, I was not a supporter of the Orion project. I was just a presenter of information that I thought would be helpful at the time. Netron radiation can degrade material. Moreover, it does nasty things that can initiate other forms of radiation when interacting with certain materials at "ground zero." In the interests of serving your post, I'll see if I can come up with something specific on the issue of neutron radiation on materials similar to the proposed puser-plate of Orion. Thank you for an intelligent post. As an aside: I have been defending the validity of the tests performed, not the validity or worthiness of the project itself. <div class="Discussion_UserSignature"> I put on my robe and wizard hat... </div>

a_lost_packet_ · Sep 20, 2004

maddad - I like the word pertinent that you used above. Orion proposes a nuclear propulsion system. If you only give it a chemical test, then you have no experimental evidence. I changed your "shouting in green text" over to a more pleasing bold. Making your letters larger doesn't increase the validity of your counter argument. You should take notes from Silylene's post. You did not understand the tests performed as they were outlined in the report. There were nuclear tests performed, specifically, in relationship to the ablation of the pusher-plate. Read it again. The chemical plasma test was only one of a series that was conducted in experiments outlined in the report. a_lost_packet_ - Will you choose to ignore all data unless it conforms to the "multiple exposure" rule? maddad - I am glad that you finally have a firm grasp of the obvious. Orion proposes multiple nuclear exposures. If you do not have experimental evidence involving multiple nuclear exposures, then you have nothing for anyone to look at and your tin hat fantasy dies right there. First off: It is not my fantasy. I linked the report in the interest of serving the discussion at hand. I have no personal interest in Orion other than discussing the possibilities and the experiments that were conducted. Specifically, I joined this thread to discuss shielding of craft traveling at a significant fraction of c. Second: You do not understand the validity of the experiments performed because you can not see the application of the data to the proposal of Orion. Whether or not this is because you did not read the report or it is due to your lack of comprehension of basic scientific inquiry is unknown. The test performed were valid experiments to determine the feasibility of proceeding with further investigation of the proje <div class="Discussion_UserSignature"> I put on my robe and wizard hat... </div>

mcbethcg · Sep 21, 2004

The interesting thing about all this to me is this: There is no such thing as a star ship. Non have ever been built. There has never been a space elevator, there has never been a solar sail, or even a test to indicate that they would work, there has never been an operating MHD drive. The only engine that has actually been tested that could possibly send a ship to another star in less than 10,000 years are ion drives, which are entirely unsatisfactory. No one has ever created sustained fusion. No one has ever collected interstellar gasses with a magnetic scoop. No one has ever created a worm hole or a warp drive or antigravity or a reactionless drive. There is only one propulsion system that has had any examination by scientists, with any experiments at all, that we know may be possible with current technology. All other systems rely on science fiction technology. You know what? maybe the orion won't work. I think it will. Maddad thinks it will not. But it is the most mature technology that has the most experimental data. And Maddad does not know much about it- he thinks that there should be 10,000,000 bombs to go to mars, for instance, as if anyone ever proposed that it be used constantly all the way there. He has a lot of other questions that he throws out, but there is no indication he knows much about them either. He talks about neutrons causing embrittlement, but does not know, obviously, that most orion plans proposed putting a hydrocarbon sheild on each bomb that would absorb the neutrons before disintegrating. Maddad is just a knee jerk anti-nuke who knows nothing about what he talks about.

silylene old · Sep 21, 2004

He talks about neutrons causing embrittlement, but does not know, obviously, that most orion plans proposed putting a hydrocarbon sheild on each bomb that would absorb the neutrons before disintegrating. Actually I believe I was the one who brought up the subject of neutron embrittlement of the pusher plate <img src="/images/icons/wink.gif" /> Please post a link supporting that a hydrocarbon shield would work (experimental data preferred, or at least a logical explanation). I am completely unaware of this concept. Hydrocarbon "shields" to my knowledge have a completely different purpose in nuclear weapons design. Typically the radiation channels within the bomb design are filled with a dense plastic foam such as polystyrene, that has been foamed with a hydrocarbon gas (pentane for example). The channel is thus filled only with carbon and hydrogen. Remember that the ionization energy of the last electron in carbon is 490 eV (hydrogen's ionization energy is a mere 13.61 eV), which corresponds to the average particle energy at a temperature of 5.7 x 10^6 K. So as the radiation channel approaches this temperature, the foam will become completely ionized and nearly transparent to thermal radiation. Polyethylene wall linings have been used instead of plastic foam (in the Mike weapon for example). Unless the casing is flushed with a low-Z gas, the higher ionization energies of nitrogen and oxygen may cause significant thermal absorption. A high radiation pressure is required for proper compression in order to maximize fusion yield. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center">- - - - - - - - - - - - - - - - - - - - - - </div><div class="Discussion_UserSignature" align="center">I really, really, really miss the "first unread post" function. </div> </div>

a_lost_packet_ · Sep 21, 2004

There is nothing that can be imagined which can not be done. - ibid I agree stevewh, there is a host of technology that is teasing our fingertips during this century. All we have to do is reach for it. <div class="Discussion_UserSignature"> I put on my robe and wizard hat... </div>

mcbethcg · Sep 21, 2004

http://encyclopedia.thefreedictionary.com/Nuclear%20kinetic%20propulsion Look at the paragraph that mentions neutrons.

silylene old · Sep 21, 2004

http://encyclopedia.thefreedictionary.com/Nuclear%20kinetic%20propulsion Look at the paragraph that mentions neutrons. Well I did: <blockquote>In reply to:<hr />Most of the three thousand tons of each of the "super" Orion's propulsion units would be inert material such as polyethylene or boron salts, used to transmit the force of the propulsion unit's detonation to the Orion's pusher plate, and absorb neutrons to minimize fallout. <hr /></blockquote> These materials would be destroyed if they were between the pusher plate and the bomb blasts on the first blast. How does the design intend to replace 3000 tons of neutron absorbing material between each nuclear detonation? <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center">- - - - - - - - - - - - - - - - - - - - - - </div><div class="Discussion_UserSignature" align="center">I really, really, really miss the "first unread post" function. </div> </div>

a_lost_packet_ · Sep 21, 2004

stevewh33- Anyone hear of any other harder than diamond substances, reported in the journals? Materials which could serve as very hard space craft hulls? Buckyballs under pressure

and their slightly flexible too!) Materials Science (Purdue Univ. towards bottom of page Borazon@ (Boron Nitride) GE Superabrasives Description-Borazon Osmium (High compression strength) Science News - Osmium Abstract - Osmium Compressibility I'm sure there are probably more and I bet I missed an obvious one somewhere. <div class="Discussion_UserSignature"> I put on my robe and wizard hat... </div>

robnissen · Sep 21, 2004

"Anyone hear of any other harder than diamond substances, reported in the journals?" Yes. Cubic zirconium reported in the journal Domus Tabernarius Circulor, authored by S. Summers.

mcbethcg · Sep 21, 2004

Its disposable. For reference: The proposed Daedalus unmanned flyby probe used 50,000 tons of (impossible to get, retrieved from the atmosphere of Jupiter) He3, and moves nothing but a set of probes. The "super orion" uses 1080 propulsion units that weigh maybe 3001 tons each (3000 tons of polyurethane) or 3 million tons, and moves a city. The Saturn V rockets to the moon weighed 6.1 million pounds when fully loaded with fuel, or 31,000 tons.

silylene old · Sep 21, 2004

mcbethq: I read it and was unimpressed. And I still don't understand how the 3000 tons of neutron absorber between the bomb and the pusher plate will be replaced after each detonation. And I don't believe polyurethane will be a very effective neutron shield either (compared to other possible materials). If this material were so good, we would use polyurethane nuclear reactor scram rods and polyurethane within nuclear reactor housings. We don't. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center">- - - - - - - - - - - - - - - - - - - - - - </div><div class="Discussion_UserSignature" align="center">I really, really, really miss the "first unread post" function. </div> </div>

mcbethcg · Sep 21, 2004

Its disposable, used once and blown to smithereens. 1080 of them would be needed, and weigh 3 million tons We don't use materials with low tolerance to heat, like polyurethane, in reactors, because they get destroyed by the heat. Great at absorbing neutrons, though.

Maddad · Sep 21, 2004

mcbethcg "You know what? maybe the orion won't work. I think it will. Maddad thinks it will not. You are correct; I do not believe that Orion would work. However, I do not know that Orion cannot work. I can only know that, one way or the other, if we obtain experimental evidence. "And Maddad does not know much about it- he thinks that there should be 10,000,000 bombs to go to mars, for instance, as if anyone ever proposed that it be used constantly all the way there. Fair enough. How much are you proposing? Power on for what, one percent of the travel time? Good thinking. Now we only need 100,000 nuclear bombs. Of course they now need to be bigger bomds, so you now need a bigger shock absorbing system, and it already would have to be gargantuan to achieve its objective. Otherwise we subject the crew and structure to even bigger stresses. And of course we lose a major claim of the Orion project. Supposedly the trip would be much shorter than other proposals because you could be under power the entire time. "He talks about neutrons causing embrittlement, but does not know, obviously, that most orion plans proposed putting a hydrocarbon sheild on each bomb that would absorb the neutrons before disintegrating. Hang on Clyde, I haven't said word one about embrittlement. That was somebody else's contribution. But now that you bring it up, you have a problem. The hydrocarbon shield will absorb some neutrons, sure, but what percentage? Suppose that it's 99%. That's an awful lot, probably more than any possible design, but let's work with that number. Ok, you need only 100,000 nuclear bombs to drive Orion to Mars, thanks to shutting off the power 29 hours into the flight. The fast neutrons from only 1% of them get through to the pusherplate, so you're subjecting the push

a_lost_packet_ · Sep 21, 2004

What do you mean when you say "harder" than diamonds? That may help narrow it down. <div class="Discussion_UserSignature"> I put on my robe and wizard hat... </div>

a_lost_packet_ · Sep 22, 2004

Even though I originally jumped in the thread because of interests in shielding, this Orion thing has gotten me interested. So, I'm running through lists of nuclear tests. <img src="/images/icons/smile.gif" /> There were a number of underground tests to determine the feasibility of containing small yield underground nuclear blasts. I believe one of the posts earlier described the "flying manhole cover." There were actually two of these types of test (Pascal A + B) which used a concrete casement and structures within that were not designed to act as a plug, but ended up trying really hard to. <img src="/images/icons/smile.gif" /> Here's a link to the tests: Plumbob (great site btw) A couple of humorous snips from the page: Pascal A test)Campbell: The first thing we at LASL did in a hole was called Pasal-A. It was 500 feet deep, in a cased hole. We put the bomb at the bottom of it, and we didn't stem it. So, we fired it. Biggest damn Roman candle you ever saw! It was beautiful. Big blue glow in the sky... Bill Ogle was out there, in that timing station. When he saw that thing come out of the ground he knew he couldn't come south the way he came or he'd get into trouble... He was really excited about how they were going to get back... They were damn lucky they didn't go right through that cloud. Carothers: Why didn't you stem it? Campbell: Didn't need to. We did have a lid on that hole. Nobody's seen it since. We never did find that. On that lid was one of Johnny Malik's detectors, and we wanted a line of sight to see if we could measure some reactions. There was a kind of plug in the hole. It was a couple of hundred feet off the bottom, as I remember. All it was, was a concrete cylinder with a hole through the center of it, so the detector could look through it. And it had an annulus, so it wouldn't bind anywhere going down. It was suspe <div class="Discussion_UserSignature"> I put on my robe and wizard hat... </div>

paradoxical · Sep 22, 2004

There is nothing stronger that diamond. Cubic zirconium is a widespread and inexpensive diamond simulant that would never stand the rigour of high speed space travel. Another substance is aerogels - which consist of highly porous glass and plastic creating one of the lightest and strongest material known. According to Sciencedaily.com, the strongest material known to currently exist is carbon nano-tubes (which is actually diamond. Is this the same as Buckytubes?). Some scientists claim that spider silk has greater structural integrity than any known substance. And finaly, Buckytubes, are the ultimate engineering polymer, 100 times stronger than steel at less than one sixth the weight

thechemist · Sep 22, 2004

According to Sciencedaily.com, the strongest material known to currently exist is carbon nano-tubes (which is actually diamond. Is this the same as Buckytubes?). Carbon nanotubes resemble more the graphite structure (hexagonal), and bear no relation to diamond's tetrahedral molecular structure. People mean different things by using words such as hard and strong, and also how the material is used (fiber or bulk) makes a difference. Diamond cannot be threaded to fibers, while the spider's web can make pretty strong (bulletproof) clothing, stronger than kevlar if I remember well. Brittleness is also a heavy issue, a pure diamond hull would not stand a chance. It would have to be reinforced by something. <div class="Discussion_UserSignature"> I feel better than James Brown. </div>

robnissen · Sep 22, 2004

"Anyone hear of any other harder than diamond substances, reported in the journals?" My response: "Yes. Cubic zirconium reported in the journal Domus Tabernarius Circulor, authored by S. Summers." Then a couple responses back stating the rather obvious that Cubic zirconium won't work. Jeez, I learned my lesson, I will never try to make a joke here. "Domus Tabernarius Circulor" is Latin for Home Shopping Network (loosely translated), S. Summers is of course that world-renowned physicist Suzanne Summers. I guess that explains why you seldom see latin humor on HBO.

A diamond hull will not be enough!

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