A diamond hull will not be enough!

[a_lost_packet_]

Lol.<br /><br />You probably worded that response so cleverly, that nobody picked up on it! <img src="/images/icons/smile.gif" /> Nice pun btw.<br /> <div class="Discussion_UserSignature"> <font size="1">I put on my robe and wizard hat...</font> </div>

 

[Maddad]

packet<br />Well, I'll be hornswaggled! You actually did find some experimental evidence, you rotten trukey you! Now I can't tell you that you have no experimental evidence. Instead I'll have to look at what your experimental evidence shows or does not show.<br /><br />First of all the spacing in the blasts is at tightest one day. The Franklin Prime blast was on 30 August 1957 and the Smoky blast one day later on 31 August 1957. Most of these tests though were five or more days apart. Orion is not a project using individual nuclear explosions, but rather a series spaced perhaps only one or a few seconds apart. A one day interval represents 10,000 times the spacing that Orion would use, so it is not helpful in showing how material would stand up to repeated nuclear explosions.<br /><br />The second problem is that while you have a manhole cover that was the subject of a test, this cover was never examined afterwards because it was never recovered. It was never subjected to a second test, and certainly not just a few seconds after the first test.<br /><br />The third problem is the railroad bridge. It took an Orion sized blast from 1,800 feet, or 550 meters, enduring "<font color="yellow">severely distorting the interior structural girders</font>. Acording to your sources the bomb would have to be within 3.5 meters of the pusherplate to be effective: "<font color="yellow">Objects can only be propelled to very high velocities by a nuclear explosion if they are located close to the burst point. . . This radius for a 300 ton explosion is 3.5 meters.</font> The proximity ratio between 550 meters and 3.5 meters puts the Orion bomb 160 times closer to the bomb than the railroad bridge. Since blast damage is related to the square of this ratio, <strong><em>the pusher plate would receive 25,000 times the structural damage that the railroad bridge took</em></strong>.<br /><br />Just like the manhole cover, you would never find the pusher plate again

 

[silylene old]

<i>The shock absorbing system needs to be 27,000 times 150 meters, or 4,000 kilometers long. I hope you have a BIG spaceship. </i><br /><br />You neglected the shock absorbing effect of 3000 tons of polyurethane between the bomb and the pusher plate. *wink* <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[a_lost_packet_]

A brief response.. I'm at work and it is difficult for me to think up creative ways to "look" productive while posting on SDC. I need a "machine that goes <i>!ping!</i>" in my office or something...<br /><br />Many simultaneous nuclear tests have been conducted. If you follow that link I posted in my post (nuclearbombsblownup.com or whatever it was) you'll see that there are a significant amount of "simultaneous" nuclear tests. I am still looking through these for "funsies" trying to see if any could relate to our discussion. That's the only reason why I haven't mentioned it before. Rebutting one of your statements with a hollow "yes we did do simultaneous nuclear testing" doesn't mean anything if it can't be applied to the conversation at hand.<br /><br />I agree that just because a "manhole cover" (collimeter plate?) achieved escape velocity it does not mean that it is applicable to the situation at hand. While it is possible that it survived, it is a moot point. We <i>ain't</i> got it to look at. However, the fact that it was deemed very probable that the plate and the previous "unintended projectile" may have survived is interesting in and of itself.<br /><br /><font color="yellow">maddad - ..the pusher plate would receive 25,000 times the structural damage that the railroad bridge took. </font><br /><br />To oversimplify a response: The railroad bridge isn't designed to be a pusher-plate for an Orion type craft.<br /><br /><font color="yellow">maddad - I was interested in how long the shock absorber would have to be to reduce the acceleration to one gravity..</font><br /><br />Why 1G? You can exceed 1G just driving around in your car. Well, driving real fast.. and swerving around a bit.. but.. I suppose if you wish to calibrate at 1G that is your perogative. Did you take into account any system to absorb the initial impact?<br /><br />I'm not sure of the reasoning used in your equation. The shock absorbing system and pusher plate of an Orio <div class="Discussion_UserSignature"> <font size="1">I put on my robe and wizard hat...</font> </div>

 

[paradoxical]

And so the thread ends.<br /><br />As I stated in the beginning, developing new propulsion or drive systems will not be a problem for the engineers of the future.<br /><br />The problem will forever be hull deterioration. Realistically, this fundamental problem will limit us to no more than 0.3C<br /><br />Unless, of course, we develop ships that can fully rejuvenate<br /><br />Or...if it is possible to bypass the ST continuum alltogether, then we wont need to give a &%$#@! about shields anyway.

 

[paradoxical]

I can't believe this forum cuts out the &%$#@! word!<br /><br />It's culturally acceptable to use it constantly where I come from <img src="/images/icons/smile.gif" />

 

[silylene old]

<i>Realistically, this fundamental problem will limit us to no more than 0.3C <br /></i><br /><br />My calculations earlier in this thread showed that 0.1C would be a problem. I suspect speeds as slow as 0.01C would be the upper limit for front shielding. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[a_lost_packet_]

Cool.. we're back on shielding!<br /><br />If there is a will there is a way. For instance, if we developed an engine that was capable of rapidly accelerating to a significant fraction of c, don't you think that the engineers who want to see it work would figure out a way to "make it happen?" You know those engineer types. They'll go through heck to see their favorite toy in action! <img src="/images/icons/smile.gif" /><br /><br />However, I agree that we just don't know "how" to shield a craft adequately when it is traveling at such speeds. I suppose the perfect shielding would be something that allowed the craft to travel in 4D space without seeming to "be in it." ie: Warping/distorting the fabric around and in front of the ship. Sort of a shield which acts as like a knife going through butter; diverting the "fabric" of ST around the ship without effecting it. Anything residing in 4D space would have no impact on the ship. Of course, this is science-fiction at this point.<br /><br />I was reading that several ideas focused on launching a shield in front of such a ship traveling at high c. The shield would remain a few kilo's ahead of the vessel and absorb the impact of small particles during travel. However, one problem came to mind: What if such a shield was diverted from it's course due to an impactor? For every action there's an equal and opposite.. oh well, you get the drift.<br /><br />I don't think that any "physical" shield will do the job that may be needed when it comes to protecting the ship from hi-velocity impactors. There has to be a better way.<br /> <div class="Discussion_UserSignature"> <font size="1">I put on my robe and wizard hat...</font> </div>

 

[a_lost_packet_]

Not to derail the shielding discussion, but I just ran across this WMV file of the Orion concept test using chemical explosives. Very cool if anyone is interested.<br /><br />Techcentralstation - Orion Test- Video<br /><br /> <div class="Discussion_UserSignature"> <font size="1">I put on my robe and wizard hat...</font> </div>

 

[bobvanx]

That video reminds me of running up walls in Marathon by shooting grenades and letting the explosions carry you up.<br /><br />Dang I hated that wet straw sound I would make when I would fall down dead.

 

[paradoxical]

Comet.<br /><br />I agree with you in so far as propulsion is currently a problem. The maximum velocity our flimsy ships reach (as they currently are) is approximately 30KM per second (Voyager 1, I believe, is travelling at about 17KM per second).<br /><br />So yes, the problem is currently propulsion.<br /><br />But let's speculate. Once we stabilise fusion power (only a matter of time, surely?) then we will easily exceed 500 to 1000 KM per second. Assuming we don't blow up our planet, if we continue developing technology at our current rate, it is feasible that in 3 or 4 generations from now we will be exceeding 0.1C.<br /><br />Shielding now becomes more critical that anything else. Do you not agree? Future generations will be more engrossed with shielding than we are with propulsion. There really is no point in even developing high speed ships without effective shields. <br />

 

[paradoxical]

Didn't mean to call you comet last time - that is your forum ranking - apologies.<br /><br />But I feel you are disregarding the fact that propulsion systems discharge particles and energy AWAY from the ship, in the opposite direction of travel. Yes there will be deterioration in the rocket bell; yes there will be enormous pressures to content with; yes we will need to contain radiation, etc, etc. But are we not allowing the propellant to escape, to create thrust? <br /><br />When you really think about it, we don’t need anything more powerful than the space shuttle’s main thrusters – current and proven technology. Now, they’re not made out of anything spectacular, just metal composites. All we need is the fuel source to be able to maintain the thrust. The space shuttle’s main thrusters are capable of full power for 7 continuous hours but only burn for 8 minutes per launch! Imagine if we could provide the fuel for 7 hours of continuous full thrust – she’d get to 100 KM per second easily. Missions to mars would be no problem!<br /><br />Meanwhile, at the bow, our ship is hitting particles head on. Sure, these particles are mostly harmless and do not have the mass to cause problems. But all it takes is one grain of gust, weighing in at 1 gram, to badly damage the hull, or at least accelerate the deterioration process. Any mission that was to last for more than a few years with a velocity in excess of 100 KM per second would massively expose our ship to hull deterioration. <br /><br />The material required to contain the propulsion system and discharge its energy would be very distinct and utterly unlike the material required at the bow to protect the ship. Anything less than carbon nano-tubes type materials or diamond would be suicide. <br />

 

[robnissen]

My belief is -- the Orion project notwithstanding -- the only feasible propulsion source for any significant fraction of c this century is a laser powered sail. And of course the advantage with the sail approach is that there is not a lot of degradation issues on the back end. Of course the disadvantage is you have huge fricken problems with degradation on the front end. That sail will be pretty volumunous and it would definitely haved to be shielded against dust. An ice shield notwithstanding, shielding may be an intractable problem for a laser powered sail.

 

[newtonian]

You all, RobNissen - I didn't read all 12 pages of this thread.<br /><br />Did anyone post on dark energy as the means of propulsion?<br /><br />I suspect that rear discharge would be frictionless.<br /><br />Suggestion: <br /><br />google word: flubber

 

[paradoxical]

...haha, the stuff dreams are made of.<br /><br />If only we could make our ship out of flubber, now that would solve some problems...

 

[mcbethcg]

Incidentally, the articles I read, about the smallest of the orions put the distance of the nukes at 30 to 100 meters at the closest. Bigger ones would be much farther away with much wider plates.<br /><br />Also, the plans I heard mention of had a maximum of 10,000 bombs, 10 g's, hundreds of meters in length.<br /><br />Thirdly, I think our discussion of neutron embrittlement might be premature. A nuclear reactor's steel parts are designed to work in an environment very close to a nuclear reaction for a period of perhap 10 to 60 years of continual exposure, and suffer from embritlement that reduces ductility. A pressure plate of an orion would be 30 to 300 meters from an intense nuclear reaction for less than a millisecond for each explosion, where there might be a maximum of 10,000 explosions, or a total of 10 seconds of intense exposure. Although I am sure that it is possible to calculate and compare the number of neutrons that enter the plate with those that enter a power plants parts, I don't personally have the skills or data or time to do so. The most I can say for sure is that it is my gut feeling that embrittlement is not even close to being an issue.<br /><br />Lastly, and I really ought to start a seperate thread on this topic, I think that it is clear that we have reached nearly the end of the era of advances in physics and engineering. There have been no huge breakthroughs in physics for 80 years and materials sciences have not advanced much in the past 40 years. The advances we have seen in rocketry have been nothing but marginal- and its not through lack of effort. Most advances have been slight improvements in efficiency and the miniturization of electronic components. Generally other than computers, machines might look different than they did in 1970, but they function pretty much the same- cars and planes and boats and rockets perform in the same ballpark. Now compare 1970 to 1936. The diminishing returns from basic research in physics and en

 

[silylene old]

<i>materials sciences have not advanced much in the past 40 years.</i><br /><br />Not true!<br /><br />buckyballs<br />buckytubes<br />high Tc metal oxide ceramics<br />nearly all organometallic compounds<br />multiply bonded non-C compounds<br />organometallic polymers (my graduate studies!)<br />polymer precursors to ceramics<br />formable hyperbranched polymers<br />conductive polymers<br />organic memory storage materials (just wait to you see what we will begin marketing in a few years)<br />advanced sintering processes<br />memory polymers<br />microcapsules<br />hollow sphere pigments<br />DUV photoresists (enabled submicron ICs)<br />dozens of new semiconductor substrates<br />PCR reaction (revolutionized biochemistry)<br />advanced CVD processing<br />light-emitting semiconductors<br />solid state lasers<br /><br />and so much more. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[petepan]

Cool video clip a_lost_packet_<br /> How ever did you stumble across it? On second thought , don't worry <img src="/images/icons/wink.gif" /> <br /><br />Cheers

 

[Maddad]

eburacum45<br />"<font color="yellow">I trust that Freeman Dyson, one of the greatest physics minds of the twentieth century, was able to propose a theoretical shock absorbing system that could absorb the first blast without being 4000 km long; you are oversimplifying to the point of spoof.</font><br /><br />Yes, I was spoofing somewhat. The inaccurate assumption I was using was that the shockabsorbing system would have the same mass as the manhole cover. The mass of the proposed system should be at least three orders of magnitude greater, meaning that you would need a shock absorber only 4 kilometers long. That's still pretty big, but then again, the shock absorbing system might be much more than just a thousand times more massive.<br /><br />Good of you to spot that.<br /><br />"<font color="yellow">Many simultaneous nuclear tests have been conducted.</font><br />From your mouth to God's ears. Give me the link.<br /><br />Maddad<br />"<font color="Lime">the pusher plate would receive 25,000 times the structural damage that the railroad bridge took.</font>"<br />packet<br />"<font color="yellow">To oversimplify a response: The railroad bridge isn't designed to be a pusher-plate for an Orion type craft.</font><br />Yes, the pusher plate is not as robust as the railroad bridge, so it cannot withstand as much in stress. It would suffer far more than the railroad bridge even if it didn't get 25,000 times the blast effect.<br /><br />"<font color="yellow">Why 1G? You can exceed 1G just driving around in your car.</font><br />Really? You feel a sustained force in excess of 1 g while you drive? Not.<br /><br />"<font color="yellow"> Did you take into account any system to absorb the initial impact?</font><br />You are the one saying that you have a shock absorbing system; I have never made any such wildly optimistic and obviously fundamentally flawed claim. Howsomever, should you have such a system, the object of its engineer

 

[Maddad]

eburacum45<br />"<font color="yellow">if you have a propulsive discharge of energy at the back end this must be more energetic than the friction at the front end; otherwise the ship would not accelerate.</font><br /><strong><em>Any</em></strong> such action at the back end will result in forward acceleration. It is only if your coefficient of <strong><em>static</em></strong> friction is greater than your motive force that you will not accelerate, and there is no static friction in space, only dynamic friction if any.<br /><br />mcbethcg<br />"<font color="yellow">the plans I heard mention of had a maximum of 10,000 bombs, 10 g's, hundreds of meters in length.</font><br />10,000 bombs limits the outward trip to 40 minutes under power. Human beings do not tolerate 10 g's for that long, and hundreds of meters will not absorb the shock.<br /><br />A problem with your thoughts on embrittlement, distance from the explosions, maximum time of exposure is that we are back to having no experimental evidence. The evidence we do have is of chemical, not nuclear, explosives, single events instead of multiple events. It suffers from the claim that there is no difference between chemical and nuclear temperatures. This absolutely requires experimental proof since the obvious is that jacking the temperature up three orders of magnitude should in fact make a difference. Remember that liquid helium is not expected to burn steel. If I insisted that it would, you would say, "Show me."

 

[a_lost_packet_]

<font color="yellow">maddad - Yes, the pusher plate is not as robust as the railroad bridge, so it cannot withstand as much in stress. It would suffer far more than the railroad bridge even if it didn't get 25,000 times the blast effect. </font><br /><br />?? The railroad bridge did not suffer as much blast damage because it had less surface area exposed to the initial blast as you suggest. However, that is slightly misleading. Not only is a pusher plate designed to withstand the initial blast, it is also designed to "ride" that blast. It isn't designed to "withstand" a blast by maintaining a static position. Think of it like a leaf on the wind. If anchored to the ground, a leaf will tear apart in a high wind. However, riding on the wavefront of a storm, the leaf is undamaged.<br /><br /><font color="orange">??? - "Many simultaneous nuclear tests have been conducted." </font><br /><font color="yellow">maddad - From your mouth to God's ears. Give me the link. </font><br /><br />I provided a link for just that topic in one of my above posts. Here ye go: Nuclearweaponarchive.org A great site and the life's work of it's author, now deceased.<br /><br />Click around abit until you find the individual tests. Look at the descriptions and firing times of "Simultaneous Tests." That is your "simultaneous test" confirmation.<br /><br /><font color="orange">a_lost_packet_-"Why 1G? You can exceed 1G just driving around in your car." </font><br /><font color="yellow">maddad - Really? You feel a sustained force in excess of 1 g while you drive? Not. </font><br /><br />Sustained? Where did I say sustained? Really maddad, such obfuscation is beneath you. Interesting word-play on your part. Such simple ploys don't work very well. Let's stay "in context" shall we? "Exceed" has a different meaning than "sustain." Don't you agree?<br /><br /><font color="orange">a_lost_pack</font> <div class="Discussion_UserSignature"> <font size="1">I put on my robe and wizard hat...</font> </div>

 

[Maddad]

"<font color="yellow"> The railroad bridge did not suffer as much blast damage because it had less surface area exposed to the initial blast</font><br />So your position is that if you add the word designed to your word processing, then it no longer matters that the blast is 25,000 times stronger, the structure is weaker, and the exposed surface area is greater? Those are parameters that design the Orion pusher plate to utterly vanish in the first blast. Buy a clue, packet.<br /><br />"<font color="yellow">??? - "Many simultaneous nuclear tests have been conducted." <br />maddad - From your mouth to God's ears. Give me the link. <br />I provided a link for just that topic in one of my above posts.</font><br />The link you provided had <strong><em>zero</em></strong> simultaneous tests. The closest you came to simultaneous was <strong><em>two</em></strong><br />tests spaced <strong><em>one day</em></strong> apart. Orion needs perhaps <strong><em>thirty</em></strong> tests space <strong><em>one second</em></strong> apart to meet its design concept. Buy a clue, packet.<br /><br />"<font color="yellow"> Sustained? Where did I say sustained?</font><br />You have to be talking sustained if you are talking about moving tens of millions of miles in just a few months. Buy a clue, packet.<br /><br />"<font color="yellow"> You're saying that a shock absorber system is "fundamentally flawed" yet you go on to say that it would be a good idea to use such in steadying the g's to close to 1g?</font><br />I make no such claim that it would be a good idea. Any idea that cannot work is not a good idea. The shock absorber would have to be impossibly long. It would have to withstand impossible temperatures, pressures, and neutron radiation. Because of this impossibility your shock absorber idea cannot work. Buy a clue, packet.<br /><br />"<font color="yellow"> Do you know anything about the testing connected with Orion?</font><br />I

 

[a_lost_packet_]

<font color="yellow">maddad - So your position is that if you add the word designed to your word processing, then it no longer matters that the blast is 25,000 times stronger, the structure is weaker, and the exposed surface area is greater? Those are parameters that design the Orion pusher plate to utterly vanish in the first blast. Buy a clue, packet.</font><br /><br />The blast for Orion would be 25,000 times stronger and the structure of the pusher plate would be weaker? Where did you get this information by the way? Twenty-five thousand times greater? Huh? Structurally weaker? What?<br /><br />The bridge was 1800 feet from the blast point. The test was codenamed "Priscilla." The actual device used was a stockpile 40kt bomb. The end yield was 37kt.<br /><br />But maddad says <b><font color="yellow">.. that the blast is 25,000 times stronger..!!</font>/b> Well maddad, where do you get your information from. I know; you make it up as you go and phrase it so it sounds "impressive" and adds credence to your suppositions. However, I assume another reader may wish to view this so I will post the truth. In my first post on this thread I linked this document (This copy is on a diff site I think, but still the same doc) Project Orion: It's life, death and possible rebirth<br /><br />However, evidently, you have not been using your critical reading skills. Therefore, in order to be of service, I will copy and paste excerpts from the article I initially posted many moons ago.(which happen to be fact)<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>...The mass of the vehicle on takeoff would have been on the order of 10,000 TONS (28); most of this mass would have gone into orbit. The bomb units ejected on takeoff would have yielded 0.1 kiloton; initially the ejection rate would have been one per second. As the vehicle accelerated the rate would slow do</p></blockquote></b> <div class="Discussion_UserSignature"> <font size="1">I put on my robe and wizard hat...</font> </div>

 

[a_lost_packet_]

For the record, I'd like to add that regardless of the content of any of my posts in response to maddad, I have no personal issues with him. I hope that he realizes this. I am just guilty of "tit for tat" I guess. In any event, let's move the thread forward. I'd like to see some ideas for shielding against high speed particles.<br /><br />Maybe we could build a shield of freeze-dried kittens? I'm sure that laboratory supply warehouses are overstocked on these since recent environmental lobbying groups have poo-poo'd on their use in high-school anatomy classes. <img src="/images/icons/smile.gif" /><br /><jk btw /><br /><br /> <div class="Discussion_UserSignature"> <font size="1">I put on my robe and wizard hat...</font> </div>

 

[jcdenton]

Packet, I hope for your sake that you back up all your posts (reports) lest there be another Great Cleansing at SDC. <img src="/images/icons/wink.gif" /><br /> <div class="Discussion_UserSignature"> </div>