Materials science

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dualstow
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Re: Materials science

Post by dualstow »

Libertarian666 wrote: Small enough balls won't have very high terminal velocities.
Or they could be made out of something that would burn up or otherwise disintegrate on re-entry.
What you you invent this and it comes to fruition, and someone nefarious builds something similar, but modified to not burn up on re-entry?
Could that be used to take out an entire nation with something like flechettes? A locust-like swarm of BB's? Or is that impractical.
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Re: Materials science

Post by Libertarian666 »

Pointedstick wrote:
Libertarian666 wrote: Hmm, I would think that the projectiles would actually be less complicated and expensive than normal artillery shells, as they wouldn't contain any explosives or detonation mechanism. They would be spin-stabilized and just open up at their intended altitude. So they would need some sort of timing mechanism but that's about it.

And of course the entire system would be a lot less complicated than systems that attempt to hit an incoming missile by aiming at it, and wouldn't be affected by course changes or the like.

What am I missing?
This pellet cloud would need to be generated pretty close to the missile itself, which suggests perfect calculation on the ground or a proximity fuze, which will add a lot to the cost. The launcher itself will be expensive, too, and some of that cost needs to be amortized into the per-shot price. A gun that can fire projectiles into the mesosphere would not be cheap, nor would the launching charge to actually propel it up to that height. Also, tungsten isn't cheap. Steel balls would be cheaper but probably less effective. Finally, there is also the military-industrial complex mark-up to contend with. Something that would be manufactured for $10 inevitably reaches a final price of $200 after its component parts have been separately built in all 50 states and shipped to China for final assembly.

Bottom line: I think $2,000 to shoot a high-tech flak shell almost into space is a very reasonable price--probably too reasonable given all the real-world complications. If the price per shot was much lower than this, it would be pretty sweet.
I'm still not getting through. I know you're smart, so it must be me.

There is NO attempt to create the pellet cloud near any missile. In fact, there is no targeting at all.

The guns put up a "fountain" of pellets around the target cities as soon as the missile launch is confirmed and the missiles are calculated to be coming into range. The shells are very low-tech, as they have no aiming or fusing. They may be engineered to unscrew after a certain number of rotations due to their spin coming out of the barrel, or perhaps need a timer to know when to disperse the pellets, but that's it. The guns keep the fountain up as long as there are incoming missiles to be destroyed. Any missiles would run the gauntlet of the pellets and be destroyed in the process.

Is that clearer?
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Re: Materials science

Post by Libertarian666 »

Tyler wrote:
Pointedstick wrote: This pellet cloud would need to be generated pretty close to the missile itself, which suggests perfect calculation on the ground or a proximity fuze, which will add a lot to the cost. The launcher itself will be expensive, too, and some of that cost needs to be amortized into the per-shot price. A gun that can fire projectiles into the mesosphere would not be cheap, nor would the launching charge to actually propel it up to that height.
My first reaction was to ditch the gun and make it satellite based.  Use the economy of scale to launch all of the pellets into space, and let the military satellites already tracking the missiles handle distribution back into the atmosphere.  At that point it's a matter of accuracy and response time.
Nope. We don't need any more space junk, and that could be used offensively. I believe it would also be much more expensive.
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Re: Materials science

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Libertarian666 wrote: I'm still not getting through. I know you're smart, so it must be me.

There is NO attempt to create the pellet cloud near any missile. In fact, there is no targeting at all.

The guns put up a "fountain" of pellets around the target cities as soon as the missile launch is confirmed and the missiles are calculated to be coming into range. The shells are very low-tech, as they have no aiming or fusing. They may be engineered to unscrew after a certain number of rotations due to their spin coming out of the barrel, or perhaps need a timer to know when to disperse the pellets, but that's it. The guns keep the fountain up as long as there are incoming missiles to be destroyed. Any missiles would run the gauntlet of the pellets and be destroyed in the process.

Is that clearer?
Ok, I think I understand now. If you are attempting to basically create a huge cloud of tiny projectiles in the atmosphere such that a missile would be forced to hit one or more pellets as it descends towards its target, I see how that would work, but I also see a couple of remaining problems:

1. Since the pellets would be in motion and affected by gravity following their release from the shell, you would need to continuously fire the flak shells into the air or else the "cloud" would rapidly disperse and be too sparse for a missile to be guaranteed to hit a pellet. Let's say I'm wrong and each shell only costs $50 (still overoptimistic IMHO). $50 per shell * 1000 guns firing 1 shell per second * 20 seconds of firing = $1,000,000 per interdiction, which is approaching the cost of anti-missile missiles, and has a much higher upfront cost for the 1,000 gun emplacements. Still feasible, but a harder sell, I think. If these guns could be mounted on trucks in quad mounts or something, that could work, as long as they could be deployed quickly enough.

2. This will create an absolutely huge quantity of potentially hazardous debris falling on the city. These kinds of balls will gum up infrastructure terribly. Think of how many will wind up in sewers. You would really need to choose a material that's hard enough but either biodegradable or capable of burning up during re-entry. I don't know as much about the physics of this so it's possible that tiny tungsten balls would vaporize, I dunno.
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Re: Materials science

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Pointedstick wrote:
Libertarian666 wrote: I'm still not getting through. I know you're smart, so it must be me.

There is NO attempt to create the pellet cloud near any missile. In fact, there is no targeting at all.

The guns put up a "fountain" of pellets around the target cities as soon as the missile launch is confirmed and the missiles are calculated to be coming into range. The shells are very low-tech, as they have no aiming or fusing. They may be engineered to unscrew after a certain number of rotations due to their spin coming out of the barrel, or perhaps need a timer to know when to disperse the pellets, but that's it. The guns keep the fountain up as long as there are incoming missiles to be destroyed. Any missiles would run the gauntlet of the pellets and be destroyed in the process.

Is that clearer?
Ok, I think I understand now. If you are attempting to basically create a huge cloud of tiny projectiles in the atmosphere such that a missile would be forced to hit one or more pellets as it descends towards its target, I see how that would work, but I also see a couple of remaining problems:

1. Since the pellets would be in motion and affected by gravity following their release from the shell, you would need to continuously fire the flak shells into the air or else the "cloud" would rapidly disperse and be too sparse for a missile to be guaranteed to hit a pellet. Let's say I'm wrong and each shell only costs $50 (still overoptimistic IMHO). $50 per shell * 1000 guns firing 1 shell per second * 20 seconds of firing = $1,000,000 per interdiction, which is approaching the cost of anti-missile missiles, and has a much higher upfront cost for the 1,000 gun emplacements. Still feasible, but a harder sell, I think. If these guns could be mounted on trucks in quad mounts or something, that could work, as long as they could be deployed quickly enough.

2. This will create an absolutely huge quantity of potentially hazardous debris falling on the city. These kinds of balls will gum up infrastructure terribly. Think of how many will wind up in sewers. You would really need to choose a material that's hard enough but either biodegradable or capable of burning up during re-entry. I don't know as much about the physics of this so it's possible that tiny tungsten balls would vaporize, I dunno.
I think it is important to remember that these guns would be fired only after a missile attack has been launched. Assuming that this plan would actually work, that "detail" greatly reduces the relative harm to the infrastructure compared to doing nothing and allowing thermonuclear devices to be detonated in or near a city...
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Re: Materials science

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Libertarian666 wrote: I think it is important to remember that these guns would be fired only after a missile attack has been launched. Assuming that this plan would actually work, that "detail" greatly reduces the relative harm to the infrastructure compared to doing nothing and allowing thermonuclear devices to be detonated in or near a city...
True, but we're comparing it not to doing nothing but rather to alternative missile defense systems which would not have the same collateral damage issue.
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Re: Materials science

Post by Libertarian666 »

Pointedstick wrote:
Libertarian666 wrote: I think it is important to remember that these guns would be fired only after a missile attack has been launched. Assuming that this plan would actually work, that "detail" greatly reduces the relative harm to the infrastructure compared to doing nothing and allowing thermonuclear devices to be detonated in or near a city...
True, but we're comparing it not to doing nothing but rather to alternative missile defense systems which would not have the same collateral damage issue.
Ok, but those are far more complex and expensive, and the complexity makes me wonder whether they could ever work in the real case. That has to be the #1 criterion... other than for the MIC, of course, which only cares that they are hideously expensive.  :P
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Re: Materials science

Post by rickb »

Did anyone play the arcade game Missile Command in their misspent youth?

Techno's idea is very similar to the winning strategy for this game.  Rather than try to shoot each missile as it arrives, you set up a protective cloud (which, in the game, sustains itself by the arrival of more missiles - the more incoming missiles the longer the protective cloud lasts).  You still need to individually shoot down the smart missiles that detect the cloud and maneuver around it.  My guess is modern cruise missiles would be a real world analog.
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Re: Materials science

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rickb wrote: Did anyone play the arcade game Missile Command in their misspent youth?
But of course. https://www.google.com/search?site=&tbm ... le+command
Misspent you say?  ???
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