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wade
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Zhukov said:Once a typical ICBM ends it's powered ascent phase and begins to coast, it is traveling 15,000 mph, is 50 miles above the surface of the earth, and is about 25 minutes away from impact. No realistic amount of additional acceleration is going to propel a platform interceptor 35,000 more miles in the next half hour that it would take the standard ICBM to reach it's target. It would instantly have to be going 70,000 mph.
Cassini was cruising a few k below 70,000 mph. It took a 45 minute burn to reach that speed once it was already in orbit and going over 4,000 mph.
But the missile starts slowing immeadiately after the boost phase ends. It then decelerates until the end of the post-boost phase which carries it from approximately 50 miles to 800 miles above the earth before it enters the mid-course phase. Plotting and achieving an intercept to such a position is not unreasonable if the the ABM is fired shortly after the ICBM. ABM warheads are smaller than ICBM's and require no re-entry sheilding. Therefore they are much lighter and can affordably be made to accelerate much faster.
Zhukov said:Diplomatic pouches would solve that problem nicely.
Hmmm.. I have never seen or heard of a diplomatic pouch large enough to hold a full size refidgerator. Anything smaller than that (and that's probably not big enough), should stand out like a sore thumb to our detection equipment.
Zhukov said:Individual missile silo operators do not have independent authority to fire. Without clearance they cannot fire at all.
So? I don't understand why you think this is relevant.
Zhukov said:Why? Are our bigger, slower, and louder ballistic missile submarines somehow impervious to the torpedos of smaller, faster, quieter boats?
I do not believe their detection systems are sufficiently advanced to overcome our advantage, and it will be a very long time before they are. Perhaps our submarine fleet needs to be improved. Should be easy to do, we can buy some real solid expertise from the former Soviet Union.
Zhukov said:You're just wrong. I've worked we these guys. I've read their papers. There are already organizations that have worked out the logistics to minute detail. It is in their estimation that a lunar base could be constructed with the first lunar crew arriving at an operational base eight years after funding was approved.
http://vulcain.fb12.tu-berlin.de/koelle/lbq/LBQ2-01.pdf
Hmm.. first off this puts the first viable operational of such a station at 2019, this is in line with what I already posted. Second, this proposal assumes 90% of the O2 required for the station can be obtained from moon bases sources, which is an unknown. Third, to work as you propose raw nuclear material has to be transported to the moon, this would be very expensive given the figures proposed.
Getting the first crew up there and getting to a point of productivity are two very different things. This whole thing is based on the idea that such a base could produce rocket fuel, which is probably not unreasonable IFF moon based sources of water can be located (or perhaps other chemicals). But to assume moon based uranium will be locatable and mineable within any reasonable period of time is wishful thinking.
Zhukov said:The additional uranium needn't have a high density to be fissile. The neutrons created from the fusion explosion induce fission absent critical mass.
Well, sort of. As I said it does not need to be weapons grade. In fact, it does not even need to be U-237, it can be U-238, but for a bigger bang mildly enriched U-237 is used. But if it is not realatively dense then it is likely to be blown away without fissioning, and the fission products are likely to be less intense. Just because it is not heavily enriched does not mean it is not heavy. In any case, you want pretty pure uranium (237 or 238), and that is heavy stuff. Don't confuse the quality of the material (in terms of weapons or non-weapons grade) with the weight of the material. To be "less dense" it would have to be less pure, and you don't want that!
Zhukov said:A fusion warhead is a more devastating weapon than a fission warhead of the same weight. A pure fission warhead of equal power to any fusion warhead would be a heavier and larger warhead would it not? A pure fission warhead would have more plutonium in it than a fusion warhead of comparable power. Do you deny this? Or was I right when I said:
By using smaller but more powerful fusion devices with only fission triggers instead of pure fission devices, we can further reduce the amount of dangerous material that must be initially launched from Earth.
Hmmm. You are over simplifying the whole thing. Let me try to explain:
First lets consider pure fission bombs. To achieve a super-critical fission reaction (nuclear blast) requires a minimum amount of fissionable material be brought to sufficient density in proper geometry to create a blast before the material melts. This is done either by slamming two componets together (uranium style bomb) or by imploding a spehrical shaped component to achieve super-critical mass. In either case there is a minimum amount of material that will achieve the desired effect, this is true whether the device is used alone as a weapon or to be a trigger for a multi-stage explosion. There is also a maximum size for such a core, if it gets bigger than this, much of the material will fail to fission, being blown away by fissioning of other parts of the reaction. So for pure fission weapons, there is a minium size of a few kilos of uranium or a bit more of plutonium, and there is a maximum size which, I believe is about 80kg (don't hold me to this, I'm not confirming this and it's been years since I took the physics class where I learned this stuff). The thing to keep in mind is that the chain reaction is caused by free neutrons, and these are achieved through the decay of the uranium or plutonium, and they determine the rate of the reaction. Highly enriched uranium or plutonium is spittiong out more neutrons per second than less enriched material, which is why the material needs to be enriched to "weapons grade".
Now, lets consider a fission-fusion bomb. This bomb consists of the bomb listed above, but in the center of it (using either two uranium or a hollow sphere of plutonium) is a material containing a lot of Hydrogen (there are a number of options). The fusion reaction takes hydrogen (each with one proton) and converts it to heavier elements (deuterium, triterium, helium-3, helium-4, etc..). Lets just consider the simplest reaction, 2 hydrogens becoming one deuterium. Each hydrogen atom has one proton, but the deuterium nucleus that is formed has two protons emits an antielectron and a neutrino. Each stage of fusion emits neutrinos. This can increase the yeild of the bomb up to about 10 fold, with most of the additional yeild being in the form of neutrinos.
Now lets consider the fission-fusion-fission bomb. This is the same as above, except the whole thing is contained inside a uranium shell. Because of the very high number of neutinos comming out of the fusion bart of the above reaction, the material does not need to be weapons grade (see U-238 and U-237 discussion above), only relatively pure. Unlike the first fission stage, quite a bit of material can be involved, because the neutrino blast is nearly instantaneous, huge by comparison with the pre-fission neutrino emmision levels of the fissionable material, and there is much less concern for perfection of geometry and no concern for pre-reaction deformation from melting prior to chain reaction. This stage can enhance the output of the bomb by 100-1000 fold or even more.
What is important to understand is that while the fission fuel (uranium or plutonium) is very dense, the fusion fuel is not. So going by weight is over-simplifying the whole thing. To get maximum effect for the total weight and size of the warhead, you really want to use the 3 stage bomb. Also, the nature of the blast from the fission reaction is much different than that from the fusion reaction, generating not only large amounts of neutrino radiation, but also large amounts of beta and gamma radiation, which in most cases are more damaging. This can be an advantage or a disadvantage depending on application.
In any case, all the figures I gave were for simple 1 stage devices or for the triggers for 2 stage devices. I never even considered adding in the outer shell to make a full on thermo nuclear warhead, specifically to minimize the amount of dangerous material being considered for launch :teeth:
Zhukov said:Wade said:Thats all well and good, except there are no pure-fusion devices.
Not that we know of.
Well, again you are reaching into science fiction. Any means of generating the necessary temperatures is, using any technology even close to what we have today, going to require a huge device by comparison with a fission trigger. I suppose several of these chemical lasers, all focused on the fusable material, might be able to cause a fusion reaction. But it is impracticle for a deliverable weapon.
Zhukov said:Are you reading anything I write? It's called a deterrent. The original statement I made was: even after we were destroyed we could fire back, and therefore the fear to attack would be too great. Of course it would destroy us, if there still was an us. In the worst case scenario that would require it's use, there would not be. The whole point is to demonstrate that there is no gain to attacking us.
If that is all you want to do, the answer is simple. We simply take a good number of our existing H-Bombs and pile them in the same location right in the center of the USA, deep within the earth. Then we say "if you strike, we will blow you up too". :alco:
Come on, it's silly. For any nuclear weapons systems to be worth the cost of building, they must offer the ability to deliver a fatal blow to the enemy, while recieving a less than fatal blow in return. I really think our existing ballistic weapons systems are sufficently protected to ensure a very large return strike capability against any enemy attack in the forseeable future. Any space based systems we put up should therefore be defensive in nature, and we should only consider such a course if we determine terrestrial based ABM systems cannot do the job.
Wade