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Xenomancers wrote: There is no reason to assume that reflective alloys are going to have a significant weight difference compared to aluminium or whatever they use in ICBM construction.
Sure there is. ICBMs (and rockets in general) are designed with obsessive concern for weight. Pretty much any design change that adds features is going to add weight, because the design is already at the minimum possible weight. If mirrors could do the job without adding weight then every ICBM would already be made out of mirrors simply for the weight reduction.
The cooling systems (if they are even needed) Could be as simple as a heat sinks on important sections of the hull. Who knows?
You know what heat sinks require? Mass. It's kind of in the definition of a heat sink. So just by having a laser exist at all I've reduced your ICBM threat as you have to replace warhead mass with heat sinks. And the heat sinks are unlikely to do anything useful. The threat with lasers is not slowly melting a hole in something, it's the explosive effect of a small area being rapidly heated and expanding. It's unlikely that a heat sink, especially one optimized for weight rather than heat transfer performance, would be able to spread out the heat before the laser blows a hole in the material.
Also, there is no such thing as "important sections of the hull". The entire missile is a critical section, because even relatively minor damage can result in aerodynamic forces tearing the missile apart. And every part of the missile is essential to its function, otherwise it wouldn't be present. For a cooling/mirror system to be effective you have to cover the entire missile with it.
Plus - there are other ways of getting a payload into orbit than building a giant rocket. You can build 2/3 stage rockets. Launch assist with space catapults. There are lots of ways to overcome adding some weight to a missile.
Those "ways" are currently wishful thinking. Weight is not a trivial problem, it's one of the most difficult engineering challenges in rocket design. You can't simply handwave it away and assume that someone will magically find a solution.
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ZergSmasher wrote: What about using a railgun to fire what is basically like birdshot at an approaching missile? Like, the shell is fired by the railgun, travels a ways, then explodes and hits the missile with a cloud of shrapnel. Then the round doesn't have to be as precisely aimed, and the missile still won't be able to easily course correct around it due to a large cloud of little metal projectiles filling the air. And a missile with armor thick enough to withstand the fast moving projectiles won't be able to launch unless it's on a really big rocket.
This would be effective in the very last fractions of a second of the intercept, allowing a very close proximity kill with the explosion instead of requiring a direct hit. It's risky (the shrapnel scatters at random and may not hit, which is why current interceptors use a direct contact kill) but having the ability could be useful if you're not confident in your ability to score a direct hit. But forget about putting a large cloud in the target's path, the sheer volume of space you'd have to cover to prevent evasive maneuvers would spread your shrapnel out at way too low a density to guarantee a hit. The most likely outcome of your idea is the incoming warhead passing right through the cloud of debris without hitting anything. You still need extremely precise guidance to get the interceptor shot very close to the target.
Of course the real answer here is matching nukes with nukes. The ideal interceptor missile is carrying a nuclear warhead of its own, ensuring a kill if the interceptor gets anywhere near its target.
Automatically Appended Next Post: As for railguns in general, forget all the nonsense about OMG DAMAGE SO FAST. The advantage of railguns is not firepower, it's safe ammunition storage. Replacing explosive shells and extremely explosive powder charges with an inert metal spike is a significant improvement in damage resistance as you no longer have to worry about magazine hits destroying your ship/tank/whatever. The rest is mostly marketing hype.
This message was edited 3 times. Last update was at 2018/07/18 08:26:06
There is no such thing as a hobby without politics. "Leave politics at the door" is itself a political statement, an endorsement of the status quo and an attempt to silence dissenting voices.
Xenomancers wrote: There is no reason to assume that reflective alloys are going to have a significant weight difference compared to aluminium or whatever they use in ICBM construction.
Sure there is. ICBMs (and rockets in general) are designed with obsessive concern for weight. Pretty much any design change that adds features is going to add weight, because the design is already at the minimum possible weight. If mirrors could do the job without adding weight then every ICBM would already be made out of mirrors simply for the weight reduction.
Modern ICBMs are already a lot heavier than they need to be, just so they can cram in more or bigger warheads if the need arises. And if all else fails they can go back to using liquid rather than solid fuel.
This message was edited 1 time. Last update was at 2018/07/18 17:11:15
Xenomancers wrote: There is no reason to assume that reflective alloys are going to have a significant weight difference compared to aluminium or whatever they use in ICBM construction.
Sure there is. ICBMs (and rockets in general) are designed with obsessive concern for weight. Pretty much any design change that adds features is going to add weight, because the design is already at the minimum possible weight. If mirrors could do the job without adding weight then every ICBM would already be made out of mirrors simply for the weight reduction.
Modern ICBMs are already a lot heavier than they need to be, just so they can cram in more or bigger warheads if the need arises. And if all else fails they can go back to using liquid rather than solid fuel.
They are NO heavier than they need to be to carry their designated number of warheads. So adding anything for defense requires removing warheads... which is a net gain for the defender who now has fewer terminal-phase targets.
And liquid-fueled missiles are even more delicate than solid fuel ones. Any damage to the body releases liquid fuel or oxidizer all over... and that stuff is corrosive like you would not believe.
Xenomancers wrote: There is no reason to assume that reflective alloys are going to have a significant weight difference compared to aluminium or whatever they use in ICBM construction.
Sure there is. ICBMs (and rockets in general) are designed with obsessive concern for weight. Pretty much any design change that adds features is going to add weight, because the design is already at the minimum possible weight. If mirrors could do the job without adding weight then every ICBM would already be made out of mirrors simply for the weight reduction.
Modern ICBMs are already a lot heavier than they need to be, just so they can cram in more or bigger warheads if the need arises. And if all else fails they can go back to using liquid rather than solid fuel.
They are NO heavier than they need to be to carry their designated number of warheads. So adding anything for defense requires removing warheads... which is a net gain for the defender who now has fewer terminal-phase targets.
And liquid-fueled missiles are even more delicate than solid fuel ones. Any damage to the body releases liquid fuel or oxidizer all over... and that stuff is corrosive like you would not believe.
Not necessarily. I don't know about American missiles, but Russian missiles are designed for variable load-outs. The amount and weight of warheads, as well as countermeasure systems, can all be adjusted depending on the target the missile is meant to go after. If a certain enemy target is heavily defended, you just use lighter warheads, or fewer heavier warheads and use more countermeasures. It is not a net gain for the defender, since that missile full of countermeasures is highly likely to destroy its target despite its lower potential destructiveness. A missile with more warheads but less countermeasures would have been more destructive in theory, but in practice it would have been shot down so it is actually less destructive than the lighter warheads of the countermeasure missile. So yes, missile defenses may force a reduction in the number of warheads a missile will carry, they do not actually reduce the dangerousness of the missiles. And yeah, you are definitely right that liquid fuel has significant drawbacks. It decreases the reliability of a missile. That is why Russia switched to using solid fuel when the Soviets had always used liquid, as liquid fuel allowed them to stuff more warheads into their missiles than the US, giving them a strategic advantage.
This message was edited 1 time. Last update was at 2018/07/19 00:57:49
Xenomancers wrote: There is no reason to assume that reflective alloys are going to have a significant weight difference compared to aluminium or whatever they use in ICBM construction.
Sure there is. ICBMs (and rockets in general) are designed with obsessive concern for weight. Pretty much any design change that adds features is going to add weight, because the design is already at the minimum possible weight. If mirrors could do the job without adding weight then every ICBM would already be made out of mirrors simply for the weight reduction.
Modern ICBMs are already a lot heavier than they need to be, just so they can cram in more or bigger warheads if the need arises. And if all else fails they can go back to using liquid rather than solid fuel.
They are NO heavier than they need to be to carry their designated number of warheads. So adding anything for defense requires removing warheads... which is a net gain for the defender who now has fewer terminal-phase targets.
And liquid-fueled missiles are even more delicate than solid fuel ones. Any damage to the body releases liquid fuel or oxidizer all over... and that stuff is corrosive like you would not believe.
Weight is probably not even the primary concern in ICBM deisgn in regards to hull materials - price/integrity/weight ratio is all part of an equation for your deisred goal. If the enemy can blow all your missles out of the sky with a death ray and all you gotta do is build out of a different material - that is where you start. It's not even a consideration to not build out of an anti laser material at that point. Also - the reflective surface could be something as simple as a coating which would ad negligible mass.
My point about heatsinks was - they could be placed in particularly vulnerable areas - you might not need a huge liquid pump.
This message was edited 1 time. Last update was at 2018/07/19 20:42:42
If we fail to anticipate the unforeseen or expect the unexpected in a universe of infinite possibilities, we may find ourselves at the mercy of anyone or anything that cannot be programmed, categorized or easily referenced.
- Fox Mulder
Zed wrote: *All statements reflect my opinion at this moment. if some sort of pretty new model gets released (or if I change my mind at random) I reserve the right to jump on any bandwagon at will.
Jadenim wrote: Weight is the primary concern of everything that flies. Every. Single. Thing.
In other news: grass is green.
Weight is not the only concern though. Designing a missile, or an aircraft for that matter, is always a process of balancing out different concerns. Absolute weight, lifting power, throw-weight, accuracy, speed, size etc.
Jadenim wrote: Weight is the primary concern of everything that flies. Every. Single. Thing.
It does not matter to the extent is being emphasized. If it provided an advantaged to build missiles with reflective hulls or coatings. It could be accomplished.
Jadenim wrote: Weight is the primary concern of everything that flies. Every. Single. Thing.
In other news: grass is green.
Weight is not the only concern though. Designing a missile, or an aircraft for that matter, is always a process of balancing out different concerns. Absolute weight, lifting power, throw-weight, accuracy, speed, size etc.
Which is what I was saying. The end goal is create a weapon that has the highest chance of completing it's goal.
This message was edited 1 time. Last update was at 2018/07/20 15:47:29
If we fail to anticipate the unforeseen or expect the unexpected in a universe of infinite possibilities, we may find ourselves at the mercy of anyone or anything that cannot be programmed, categorized or easily referenced.
- Fox Mulder
Xenomancers wrote: It does not matter to the extent is being emphasized. If it provided an advantaged to build missiles with reflective hulls or coatings. It could be accomplished.
Sure, it could be accomplished, but at immense cost in complexity and payload capacity. And if building an anti-ICBM laser results in you losing 90% of your total throw weight, well, I've just crippled your force before I fire a single shot. And the laser is still probably going to shoot down some of the missiles you do manage to build. Then my kinetic interceptors are going to have a much easier time, since there are so many fewer incoming threats to intercept. It's quite possible that the situation even gets to the point where your deterrent is no longer effective and I can (and do) launch a preemptive first strike to permanently remove you as a threat.
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Xenomancers wrote: Also - the reflective surface could be something as simple as a coating which would ad negligible mass.
There is no such thing as negligible mass in rocket design.
My point about heatsinks was - they could be placed in particularly vulnerable areas - you might not need a huge liquid pump.
Again, there is no such thing as "particularly vulnerable areas" on an ICBM. Every single component of the missile is vulnerable, because if it wasn't essential to the successful operation of the missile it wouldn't be included. And even relatively minor damage to any part of the exterior of the missile is likely to be a kill as aerodynamic forces tear it apart, so the entire exterior surface of the missile would have to be coated in reflective material and backed by heat sinks.
This message was edited 2 times. Last update was at 2018/07/20 22:17:38
There is no such thing as a hobby without politics. "Leave politics at the door" is itself a political statement, an endorsement of the status quo and an attempt to silence dissenting voices.
1) The vast majority of the missile is fuel tanks, something like 90%. Most of the rest is the warheads and the engines. The electronics are vanishingly tiny in that big missile.
2) Having the equivalent of a stick of dynamite go off on the skin over the 90% that is fuel tanks will either rupture the tank, causing the fuel to detonate, or cause the solid fuel to shatter, causing it to detonate.
A megawatt laser will deliver that stick of dynamite through any conceivable mirror that can be mounted on a ballistic missile and still leave a useable payload, and will survive the trip out of the atmosphere.
Sure, it's possible that something new will come along and change that... just as right now we don't have any megawatt lasers in space that can deliver their throughput at a realistic distance. But the laws of physics say it doesn't look good.
This message was edited 1 time. Last update was at 2018/07/20 22:35:06
