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#21
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Armadillo Aerospace drop test
George William Herbert wrote:
Kaido Kert wrote: I agree with everything you say, but i have this one important nitpick: rocket technology equals missile technology NOT. While its true that most modern missiles of all kinds are propelled by various rocket engines, a rocket is not a missile. There are other things that missiles need, other than what a space launch type rocket can bring to the table. And military applications tend to optimize on solution spaces differently than space launch (storability, etc being larger concerns). However, the dual use nature and convertability ^^^^^^^^ ah, see there is a big problem here. As things stand you end up with a big mondo list, that just about includes "soap" (armies have to wash themselves every now and then) and shoclate (aka high energy food you might pack for your troopps). Not only is teh notion and lits of dual-use goods ill-thought out concept, it is also in its present incarnation wrong, irrelevant and there is no meaningful oversight what appers in it. of many space launch systems to weapons purposes is hard to avoid. A lot of CATS amateurs haven't looked at the military side enough to understand that the differences between modern rockets and missiles don't mean there isn't a significant dual use problem. There is. Really. Even John Carmack's and Burt Rutan's equipment could be made into medium grade SRBMs, the Armadillo stuff without too much effort. you should take a look at the 'how to build a cruise missle with $5000' page from New Zealand... IIRC no dual use goods at all were involved. Over the long term (20 years) proliferation of low cost rocket technology is a lost cause IMHO. It is lost *now*. For that matter, I cant'tthink of any reasson why one would claim this was not always the case in the first place. Over the medium term (5-10 years) how we treat the technology in terms of level of detail we publish and allow foreigners open access to could make a large difference in hostile nations capability growth. This is fundametaly wrong - it has been demonstrated times and times again by states other than the US that the US has no monopoly on bright minds who grok rockets. All the present mindless thrashing what can and cannot be published will result is in a stunted growth rate for sciences inside the US. This is not an ideal situation, but it is reality. But a changable part of it. -george william herbert -- Sander +++ Out of cheese error +++ |
#22
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Armadillo Aerospace drop test
Sander Vesik wrote:
George William Herbert wrote: However, the dual use nature and convertability ^^^^^^^^ ah, see there is a big problem here. As things stand you end up with a big mondo list, that just about includes "soap" (armies have to wash themselves every now and then) and shoclate (aka high energy food you might pack for your troopps). Since the other side (whoever they are) already knows how to make soap and chocolate, there's no problem. Not only is teh notion and lits of dual-use goods ill-thought out concept, it is also in its present incarnation wrong, irrelevant and there is no meaningful oversight what appers in it. Dual use is a useful concept when talking about technologies that the other side (potential enemies) does not have easy access to. Rocket engines and guidance systems are exactly such technologies when the potential enemies in question are Iran, North Korea, or nations at a similar stage of technological development. There is no way a reasonable person can conclude that such nations would not be helped in their weapons development program by technologies currently being developed for X-Prize class vehicles. There may be differences in certain details between weapons-optimized engines and guidance and transport-optimized engines and guidance, but there is unquestionably a significant overlap. There is a separate issue of whether export restrictions are effective, and whether alternative strategies (such as a vigorous missile defense program) might provide better security. you should take a look at the 'how to build a cruise missle with $5000' page from New Zealand... IIRC no dual use goods at all were involved. The cruise missile in question has never flown. Even if it had flown, it has no bearing on other technologies that might be used to make weapons. This keeps coming up when possible use of rocket related technologis to build weapons is discussed - people start designing alternative weapons systems and tactics for terrorists to use, and claiming that they are simpler than slapping a stick of dynamite on a model rocket. Even if true, it doesn't impact the utility of rockets. Similarly, even if the garage cruise missile works, it says exactly nothing about the utility of transportation rocket engines and guidance systems for military purposes. Over the long term (20 years) proliferation of low cost rocket technology is a lost cause IMHO. It is lost *now*. For that matter, I cant'tthink of any reasson why one would claim this was not always the case in the first place. Because North Korea has been having a hard time getting their long range missiles to work. The fact that they've had some recent successes is no argument for making their task any easier. Over the medium term (5-10 years) how we treat the technology in terms of level of detail we publish and allow foreigners open access to could make a large difference in hostile nations capability growth. This is fundametaly wrong - it has been demonstrated times and times again by states other than the US that the US has no monopoly on bright minds who grok rockets. And it has been demonstrated time and again that people outside the US have had their tasks made easier by access to technologies from within the US (and vice versa). The stupidity of US export regulations in their current form should be understood for what it is - an overreaction to a real problem, not simple random idiocy. .......Andrew -- -- Andrew Case | | |
#23
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Armadillo Aerospace drop test
Sander Vesik wrote:
George William Herbert wrote: Kaido Kert wrote: I agree with everything you say, but i have this one important nitpick: rocket technology equals missile technology NOT. While its true that most modern missiles of all kinds are propelled by various rocket engines, a rocket is not a missile. There are other things that missiles need, other than what a space launch type rocket can bring to the table. And military applications tend to optimize on solution spaces differently than space launch (storability, etc being larger concerns). However, the dual use nature and convertability ^^^^^^^^ ah, see there is a big problem here. As things stand you end up with a big mondo list, that just about includes "soap" (armies have to wash themselves every now and then) and shoclate (aka high energy food you might pack for your troopps). Not only is teh notion and lits of dual-use goods ill-thought out concept, it is also in its present incarnation wrong, irrelevant and there is no meaningful oversight what appers in it. I'm sorry, but that is just idiotic. We are not discussing food or bathing products. We are discussing vehicles that travel at supersonic, hypersonic, or orbital velocities with small to large payloads, with precision guidance systems. You could turn the Armadillo vehicle into a SRBM with a 3-person-weight HE bomb and a software update. That is one of the very good reasons that governments want to monitor and provide oversight on launch type activities. Declaring that space launchers, even reusable ones, are not capable of being used for military purposes or being developed into militarily useful weapons systems is wrong. This point is not debatable. Some of them make remarkably bad weapons. The current lines drawn regarding the risks of various technologies are arguably wrong. But space launch *is* a major missile technology proliferation risk area. Period. you should take a look at the 'how to build a cruise missle with $5000' page from New Zealand... IIRC no dual use goods at all were involved. The question is not 'can one proliferate missiles without using dual use or space launch tech'. The question is, 'does space launch tech constitute a missile technology proliferation risk' and the answer is Yes. Over the long term (20 years) proliferation of low cost rocket technology is a lost cause IMHO. It is lost *now*. For that matter, I cant'tthink of any reasson why one would claim this was not always the case in the first place. How many foreign missile programs have you studied? I have studied enough to have contributed some of the early analysies of looking at Japan's space launchers as a candidate ballistic missile project, and looked at other nations varied ballistic missile projects in a fair depth. What we're doing here now in the US is a lot different and potentially a lot cheaper. It is going to get out eventually, and possibly sooner rather than later, but it getting out to some people is clearly a bad thing. Sticking your head in the sand about the problem and risks is not a technically, politically, or morally reasonable attitude. There is no clear right answer, and I am certainly not happy with where the laws are now and some of the restrictions. But the core issues are real and serious. -george william herbert |
#24
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Armadillo Aerospace drop test
On Wed, 9 Jul 2003 10:32:59 +0200, in a place far, far away, "Ultimate
Buu" made the phosphor on my monitor glow in such a way as to indicate that: Welcome to the world of high density fuels and non-NASA designs. Why does it look a little small to you? If you read the web page you will note that this drop was done with the smaller of two tanks, and if it turns out they need more fuel, they will just swap tanks. Now that is what simple designs let you do. If you read the rest of the website you will see that flight hops and test firng of the engines already means they know thier fuel requirements. I always assumed that hydrogen peroxide packed a much smaller punch per pound and that therefore a lot more fuel would be needed. If it works with this or a slightly larger tank, so much the better! But if it works, I'm starting to wonder why al other rockets have to be so large and cumbersome compared to John's elegantly small design. John's design is small because it isn't going to orbit. Most "other rockets" do... -- simberg.interglobal.org * 310 372-7963 (CA) 307 739-1296 (Jackson Hole) interglobal space lines * 307 733-1715 (Fax) http://www.interglobal.org "Extraordinary launch vehicles require extraordinary markets..." Swap the first . and @ and throw out the ".trash" to email me. Here's my email address for autospammers: |
#25
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Armadillo Aerospace drop test
Hi Mr Carmack,
Your site weblog said the following: "When we got it back to the shop, we pulled some things apart to take a closer look. The bent mounting studs unscrewed right out of their mounts, so replacing those is trivial. We are considering adding some more bracing below the engine plates, which would probably keep them from bending at all. When we got the crush cone off, we did find that the cabin had been bent right at the end of the cone, and the buckle in the crush cone had pushed in far enough to crease the honeycomb bulkhead." Well, my understanding is that there are now various grades of carbon-fiber loaded engineering polymer resins on the market, which show more flexion under stress and have pretty high strength. They would likely provide weight savings relative to whatever alloy you're using, and can more readily be formed into parts. Have you ever considered using something like that for part of your spacecraft? Perhaps an inner hull, just to ensure pressure integrity in the face of repeated usage? Maybe the key to a simpler but successful design is in more expensive, better-performing materials. |
#27
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Armadillo Aerospace drop test
In article ,
John Carmack wrote: ...opting for an ogive nose cone instead of a conical one could quadruple the cost, or more, for very minor theoretical gains... And often you can do almost as well with a little cleverness. For this particular example, a double cone (starting with a gentle taper and then switching abruptly to a steeper one partway up) gets you most of the benefit of an ogive without the fabrication difficulties. -- MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer first ground-station pass 1651, all nominal! | |
#28
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Armadillo Aerospace drop test
Earl Colby Pottinger writes:
Myself, would have to say "The key to a simpler but successful design is build it cheap, test it and find the places where you need more expensive, better-performing materials. " One of NASA's big problems was they tend to build with only more expensive, better-performing materials. I used to work with a programmer that had a NASA like philosophy when it came to writing code. Got all worried about the performance of lists that contained, at most, a few hundred entries of less than 1k of data each, even though you'd only access those once per scenario. Spent way too much time writing special purpose code to store the things in a fast hash table instead of just sticking them in a simple list. Deeper in the scenario, there were lists that contained, at most, a million entities, also less than 1k in size. Guess where most of the CPU time was really spent? Guess where we really needed to work on the code to increase performance? Sometimes, making it "better" is a waste of time, effort, and money. Jeff -- Remove "no" and "spam" from email address to reply. If it says "This is not spam!", it's surely a lie. |
#29
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Armadillo Aerospace drop test
(John Carmack) wrote in message . com...
All we need is a little more bracing in a couple places, no big deal. There are Really Large benefits to working with relatively low strength aluminum for development projects. You can weld handles on, grind them off, drill holes all over the place, then fill them back in, and it doesn't really effect the strength of the design. If you started with a highly optimized alloy or composite system you could save weight, but every modification would impact the design. High tech composites often don't like random holes being punched in them, and strong metals usually can't be welded without ruining the heat treatment. Well, I'd read about foamed metals being investigated by the big automakers for bumpers with better impact-absorption. Apparently, foamed metal can absorb impact energy better due to what they call "cell collapse" effect. Since a cone is a simple shape, have you considered taking an off-the-shelf cylindrical stock-shape made out of foamed aluminum, and machining it into the cone shape for your crush cone? Consider that foamed metal parts are significantly lighter, and are easily machined. I've also read it has excellent electromagnetic shielding properties, which can protect whatever computer crap you have on the inside. http://www.itc-g.com/IPM/FA.htm http://www.mb2010.com/research/foamed_metals.html It was also rather surprising how much cheaper rolled aluminum construction was. For complex curves like airfoils, composites are often cheaper to fabricate, but if your design can be built with just sheet metal brake and roll work, it is much cheaper, because the final product is completely self supporting during fabrication. There is a good lesson here -- opting for an ogive nose cone instead of a conical one could quadruple the cost, or more, for very minor theoretical gains. Fabrication difficulties are easy to overlook when making clean sheet designs. Gee, since your computer-heavy reputation is well-known, I'd assumed your efforts were very CAD-intensive. Is the prototyping all being done in the workshop? What are you doing in the way of CAD, or even flight dynamics simulation? The basic idea of using exotic materials to simplify the rest of the design has a lot of merit, but we haven't hit on a poster-child case for it yet. I spent a good chunk of money researching radiatively cooled engines of exotic construction: TZM (moly alloy) base with a disilicide oxidation protection coating, sealed to the injector with a silver plated, nitrogen pressurized metalic O-ring. It was very simple, and it worked, but it cost a LOT, and there were unanswered fabrication questions in scaling it up from the 50lbf size we tested with to the 1500lbf size we were looking at. When we found that we could make regeneratively cooled engines out of plain old aluminum without too much trouble, we dropped the exotic material work. Somewhat more complex plumbing, but much easier to fabricate and scale. The poster-child for exotic materials that I hope for is nanotube composites allowing pressure fed SSTO designs with conventional propellants. John Carmack www.armadilloaerospace.com Yeah, the nanotube stuff will be the coolest once it comes out. Hopefully that would be available in 10 years time. Apparently, some guy came out with a simple dipping method that could be used to build a laminate structure (perhaps a spaceship hull?). All you'd need is a vat with your nanotube solution and a vat with polymer resin. The only problem is the availability of the blessed nanotubes. http://www.nature.com/nsu/021007/021007-13.html Probably stuff you'd already heard about, but just food for your thought anyway. Maybe if you stay in the rocket business, you can eventually incorporate this stuff in v4.0! |
#30
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Armadillo Aerospace drop test
On 14 Jul 2003 16:51:44 -0700, (sanman) wrote:
Well, I'd read about foamed metals being investigated by the big automakers for bumpers with better impact-absorption. Apparently, foamed metal can absorb impact energy better due to what they call "cell collapse" effect. ....What's interesting is that I've heard of additional research in the auto *repair* industry about producing metal foamers that are relatively inexpensive to use to repair tears and holes in bumpers and doors as opposed to Bondo jobs. I figure within 5 years you'll be able to buy it at Auto Zone for $10 a can. OM -- "No ******* ever won a war by dying for | http://www.io.com/~o_m his country. He won it by making the other | Sergeant-At-Arms poor dumb ******* die for his country." | Human O-Ring Society - General George S. Patton, Jr |
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