Defense against Hypersonic Glide Vehicles

[sferrin]

...Just use kiloton-scale nuclear warhead on SAM. It would compensate the lack of accuracy.

Uhm, how about no?

 

[edwest4]

I second your no. The heating problem would be a point of weakness. Also to be considered is the relatively short transit time of a hypersonic warhead flying a depressed trajectory. To put a reverse on an old saying: They said it couldn't be done but we did it anyway.

 

[Dilandu]

Uhm, how about no?

Why? It's a simplest effective solution.

 

[sferrin]

Uhm, how about no?

Why? It's a simplest effective solution.

Does it really need to be explained? Okay, say you have a conventionally armed glider coming at your overseas base. You want to set off a nuke over foreign territory (or even if it were your own) for a couple hundred pounds of high explosive?

 

[Dilandu]

Does it really need to be explained? Okay, say you have a conventionally armed glider coming at your overseas base. You want to set off a nuke over foreign territory (or even if it were your own) for a couple hundred pounds of high explosive?

First of all: how I should know what exactly is those glider carrying? Is it labeled? Or would the enemy be so kind to allow be to inspect this glider before launching it? The only situation when the assumption that glider is strictly conventional is if it is launched by non-nuclear power; but problem is, that there isn't exactly much non-nuclear powers that could build hypersonic weapons.

Secondly, what's the problem with nukes? As long as the only thing affected is the unmanned glider, it is not the reason for escalation. Low-yield nuke altitude airburst would not create any noticeable fallout.

Thirdly, if the target is, say, aircraft carrier - which cost billions, and housed thousands of highly trained crewmembers - then the costs should be estimated in compairson with the possibility of carrier's loss. Do you agree that the probability of losing a major warship justify the use of defensive nukes?

 

[Forest Green]

First of all: how I should know what exactly is those glider carrying? Is it labeled? Or would the enemy be so kind to allow be to inspect this glider before launching it? The only situation when the assumption that glider is strictly conventional is if it is launched by non-nuclear power; but problem is, that there isn't exactly much non-nuclear powers that could build hypersonic weapons.

Secondly, what's the problem with nukes? As long as the only thing affected is the unmanned glider, it is not the reason for escalation. Low-yield nuke altitude airburst would not create any noticeable fallout.

Thirdly, if the target is, say, aircraft carrier - which cost billions, and housed thousands of highly trained crewmembers - then the costs should be estimated in compairson with the possibility of carrier's loss. Do you agree that the probability of losing a major warship justify the use of defensive nukes?

Small problem of an EMP over potential friendly foreign territory. Sorry, I just switched off all your hospital life-support machines, emergency comms and ATC network.

 

[sferrin]

Does it really need to be explained? Okay, say you have a conventionally armed glider coming at your overseas base. You want to set off a nuke over foreign territory (or even if it were your own) for a couple hundred pounds of high explosive?

First of all: how I should know what exactly is those glider carrying? Is it labeled? Or would the enemy be so kind to allow be to inspect this glider before launching it? The only situation when the assumption that glider is strictly conventional is if it is launched by non-nuclear power; but problem is, that there isn't exactly much non-nuclear powers that could build hypersonic weapons.

So? How many nuclear powers have launched cruise missiles, many of which come in nuclear variants, over the years? NOBODY is going to assume a weapon is nuclear unless it's going to land in the Continental US.

 

[rooster]

Tend to agree with you sferrin, but I think you can add Israel to the short list. If they see a cruise missile coming at them from Iran, I would bet they think its a first strike.

 

[rooster]

Currently there are no lasers yet planned to be fielded to intercept ballistic, let alone HGVs as far as I know. Hypersonic targets already have pretty good heat shields, and depending on the distance of the laser trying to hit it that would be quite a challenge. Probably a mobile nuclear reactor might be good start before having plans of hitting hypersonic targets.

It might be easier than you think. HGV bodies are already under a lot of stress, even the slightest damage would send it out of control, and a little added heat to something already heated near the limit would surely cause damage.

It also imposes design costs on your adversary which is an important considerations as well.

I would think missiles and aircraft are the easiest to destroy unlike anything that floats or "crawls" and the energy isn't much. For gosh sakes we've been planning on lasers seriously since the 80s. Just need to compromise the skin. A missile hitting a maneuvering hypersonic missile seems to expensive and extremely complex and will take a decade to field something even with a low probability of kill.

 

[bring_it_on]

It also imposes design costs on your adversary which is an important considerations as well.

I would think missiles and aircraft are the easiest to destroy unlike anything that floats or "crawls" and the energy isn't much. For gosh sakes we've been planning on lasers seriously since the 80s. Just need to compromise the skin. A missile hitting a maneuvering hypersonic missile seems to expensive and extremely complex and will take a decade to field something even with a low probability of kill.
[/QUOTE]

And you are grossly underestimating the complexity of using to take out a BGV. It would probably require multiple MW class SSL to get the altitude, distance and range even for point defense. Laser scaling efforts right now are looking at a much smaller lasers than that and it will take time to scale to that size and still provide a tactically deployable system. Kinetic options in the meanwhile are much easier to field earlier though they will most certainly be expensive. Ballistic Missiles are required to hang around in the atmosphere for tens of seconds. Boost Glide Vehicles on the other hand are likely to have flight within the atmosphere measured in minutes. They are designed to be more robust and resistant to the thermal challenges that the mission confronts.

 

[In_A_Dream]

And you are grossly underestimating the complexity of using to take out a BGV. It would probably require multiple MW class SSL to get the altitude, distance and range even for point defense. Laser scaling efforts right now are looking at a much smaller lasers than that and it will take time to scale to that size and still provide a tactically deployable system. Kinetic options in the meanwhile are much easier to field earlier though they will most certainly be expensive. Ballistic Missiles are required to hang around in the atmosphere for tens of seconds. Boost Glide Vehicles on the other hand are likely to have flight within the atmosphere measured in minutes. They are designed to be more robust and resistant to the thermal challenges that the mission confronts.

There may be other types of weapons systems that can destabilize a relatively large area prior to any launch occurring, should we have enough warning. Doesn't necessarily have to be nuclear.

In terms of mid-course interception, space based DEW (once the technology matures) will be a preferable option. There isn't much air density protecting the GV at that point.

 

[Dilandu]

Small problem of an EMP over potential friendly foreign territory. Sorry, I just switched off all your hospital life-support machines, emergency comms and ATC network.

Sigh. We are not talking about space explosions, you know. Small burst on 5-10 km altitude would create no such effect.

So? How many nuclear powers have launched cruise missiles, many of which come in nuclear variants, over the years? NOBODY is going to assume a weapon is nuclear unless it's going to land in the Continental US.

To put it simply: you are absolutely wrong. Hypersonic missiles are costly. They aren't as cheap as subsonic cruise missiles. If against you a hypersonic missile was launched, it is more logical to assume that it is actually nuclear.

 

[Forest Green]

Sigh. We are not talking about space explosions, you know. Small burst on 5-10 km altitude would create no such effect.

HGVs will not be travelling at 5-10km altitude, or even close to that, but a nuke at that altitude would still create an EMP and probably smash windows too, then there's the fallout.

 

[Dilandu]

HGVs will not be travelling at 5-10km altitude, or even close to that, but a nuke at that altitude would still create an EMP and probably smash windows too, then there's the fallout.

Sigh.

1) HGV closing to the target would be at much smaller altitudes.

2) To get the EMP, you need an altitude of at least 20-40 km. Otherwise the gamma ray deposition would be far too low to produce enough high-energy electrons.

3) A kiloton-scale explosion on 5 km would literally cause zero effect on the surface. The range of 1 psi overpressure for even SURFACE kiloton blast would be about 1,2 km. Even without counting the thinner air on 5 km altitude, it is utterly impossible for 1-kiloton blast on 5 km altitude to break any windows even directly beneath the bomb. The distance is far too high.

4) There is NO fallout. The only matter that contact with the nuclear fireball is the missile itself, which is of very little mass. The amount of radioactive byproducts that you could manage of one-ton missile body would be minuscule, and due to altitude, they would be dispersed in air streams to almost-undetectable concentration long before they would descend on the surface.

Seriously, your knowledge of nuclear weapon seems flawed.

 

[sferrin]

To put it simply: you are absolutely wrong. Hypersonic missiles are costly. They aren't as cheap as subsonic cruise missiles. If against you a hypersonic missile was launched, it is more logical to assume that it is actually nuclear.

In the real world, not Call of Duty, that is not the case. If I know a couple B-2s are forward deployed to Guam a half dozen hypersonic glide vehicles to kill them would be a bargain. Nobody's ever suggested we defend empty tents with missile defense.

 

[Dilandu]

In the real world, not Call of Duty, that is not the case.

Newsflash: there is no "save/load" option in real world. That's why military always tried to prepare for the worst possible scenario.

If I know a couple B-2s are forward deployed to Guam a half dozen hypersonic glide vehicles to kill them would be a bargain.

As well as using nuclear interceptors to stop them. It would still be far less costly than failing to intercept them at all.

 

[sferrin]

In the real world, not Call of Duty, that is not the case.

Newsflash: there is no "save/load" option in real world. That's why military always tried to prepare for the worst possible scenario.

If I know a couple B-2s are forward deployed to Guam a half dozen hypersonic glide vehicles to kill them would be a bargain.

As well as using nuclear interceptors to stop them. It would still be far less costly than failing to intercept them at all.

Okay sweetie. Buh bye.

 

[Dilandu]

Okay sweetie. Buh bye.

I take it that you do not have any other arguments except "it would be politically incorrect"?

 

[GARGEAN]

Nuke going off at 100+km heigh is not exploding "over someone's terrain". It's exploding in space won't affect any county legally. Nor it will physically: there is no chance small (or even not that small) yield warhead will disable "life support systems" in hospital even if said hospital was at zeroed vector under it.

 

[Forest Green]

Sigh.

1) HGV closing to the target would be at much smaller altitudes.

2) To get the EMP, you need an altitude of at least 20-40 km. Otherwise the gamma ray deposition would be far too low to produce enough high-energy electrons.

3) A kiloton-scale explosion on 5 km would literally cause zero effect on the surface. The range of 1 psi overpressure for even SURFACE kiloton blast would be about 1,2 km. Even without counting the thinner air on 5 km altitude, it is utterly impossible for 1-kiloton blast on 5 km altitude to break any windows even directly beneath the bomb. The distance is far too high.

4) There is NO fallout. The only matter that contact with the nuclear fireball is the missile itself, which is of very little mass. The amount of radioactive byproducts that you could manage of one-ton missile body would be minuscule, and due to altitude, they would be dispersed in air streams to almost-undetectable concentration long before they would descend on the surface.

Seriously, your knowledge of nuclear weapon seems flawed.

1. Nobody wants to leave an intercept that late.

2. Nope. And have you considered air traffic both wrt the EMP and the explosion?

3. Too bad for any aircraft inside 1.2km.

4. Depends entirely on the weather.

 

[sferrin]

Not to mention right now the threshold for using a nuclear weapon is extraordinarily high. Do we really want to make it common? And it's not like micro-nukes haven't been considered before. Back in the 80s they were kicked around for Mk48 & Mk50 torpedos to deal with large, double-hulled Soviet subs. The thinking was way out at sea, underwater, maybe nobody would care, or at least not as much. Even then they decided against it. If they're not willing to use a tiny nuke against a Typhoon carrying a couple hundred nukes there's no way a glider is going to have nukes tossed at it.

 

[Dilandu]

1. Nobody wants to leave an intercept that late.

Agreed, but since you could not guarantee intercept on earlier stages - it is better to have last-ditch weapon with high intercept probability.

2. Nope. And have you considered air traffic both wrt the EMP and the explosion?

You seems to not understood at all, how the nuclear EMP works...

3. Too bad for any aircraft inside 1.2km.

I'm sorry, what exactly are the probability that some aircraft would be exactly in the range of burst? You seems to not understood, that situations when aircraft are closing with each other are quite rare outside the intense traffic corridors.

4. Depends entirely on the weather.

Sigh. Now I knew that you have absolutely no idea about nuclear weaponry.

Watch this:

This is a footage of AIR-2 Genie nuclear air-to-air rocket (not missile; it was unguided), airburst in 1957 live test. The 2-kt weapon was detonated on roughly 5600-6000 meters altitude, exactly over the group of observers, which stand directly under explosion.

No one of them was harmed. The dose of radiation they received was negligible.

There is NO fallout from altitude bursts. The fallout is a result of matter from surface being drawn into a fireball, irradiated, and them sucked upward into atmosphere with hot air current. But if fireball did not have contact with surface, the only matter in contact with fireball is the missile itself. Which is a Really Tiny Mass, that simply could not provide enough matter for irradiation - regardless of weather!

 

[Dilandu]

Not to mention right now the threshold for using a nuclear weapon is extraordinarily high. Do we really want to make it common?

As a defensive measure against enemy weapon system - why not? No men would be harmed from nuclear anti-missile hitting HGV, you know.

Stop worrying and love the bomb, frankly. If the clever solutions failed to work, it's time for a good ol' brute force to do the job.

 

[Dilandu]

P.S. There is one alternative to nuclear SAM's that MAY be effective against HGV's. It is orbital laser array of megawatt-class, capable of burning through HGV heat protection.

The HGV's are more vulnerable to lasers than usual ballistic RV's. There are two reasons to that:

* HGV trajectory is partially-atmospheric, and they are subjected to rather high thermal loads while still on mid-course. While ballistic RV only subjected to high thermal load during the last phase of its flight.

* HGV could not be hidden in a cloud of decoys. To imitate the HGV flight, such decoys essentially must be a HGV's by themselves (which is not cost-effective). I.e. it could not hide in a cloud of cheap, numerous inflatable balloons, chaffs, ect.

So, if you have something like good ol' Zenith Star - more than one, actually - on orbit, you could stop HGV's without getting into nuclear area.

 

[Desertfox]

For the record the Russians currently field nuclear-tipped interceptors and their ICBM-range HGVs are most certainly nuclear-armed.

If the target is a tactical conventionally-armed HGV, then sure try to kill it with kintetics or lasers, but if the target is a nuclear-armed HGV, I would much rather take a high-altitude kiloton nuclear blast over a ground-level megaton blast, especially if the probability of kill is much higher with the nuclear-tipped interceptor.

 

[Dilandu]

For the record the Russians currently field nuclear-tipped interceptors and their ICBM-range HGVs are most certainly nuclear-armed.

Yep. We still have our A-135 ABM system around Moscow, which is slated to be refitted into A-235 model. So, at least Moscow region have protection against hypersonics.

If the target is a tactical conventionally-armed HGV, then sure try to kill it with kintetics or lasers, but if the target is a nuclear-armed HGV, I would much rather take a high-altitude kiloton nuclear blast over a ground-level megaton blast, especially if the probability of kill is much higher with the nuclear-tipped interceptor.

Absolutely.

 

[edwest4]

What kind of warhead is supposedly carried by these HGVs?

 

[Desertfox]

The newly deployed Avangard reportedly has a nuclear warhead. Since its an ICBM-class system using silo-based ICBM boosters, it would not make sense for it to have a conventional warhead. If an Avangard were to be fired the US would most likely assume it was nuclear and respond accordingly.

Avangard | Missile Threat

The Avangard is a hypersonic boost-glide vehicle currently in development. It is one of Russia's six “next generation” weapons announced in March 2018.

missilethreat.csis.org

 

[Forest Green]

1. Nobody wants to leave an intercept that late.

Agreed, but since you could not guarantee intercept on earlier stages - it is better to have last-ditch weapon with high intercept probability.

2. Nope. And have you considered air traffic both wrt the EMP and the explosion?

You seems to not understood at all, how the nuclear EMP works...

3. Too bad for any aircraft inside 1.2km.

I'm sorry, what exactly are the probability that some aircraft would be exactly in the range of burst? You seems to not understood, that situations when aircraft are closing with each other are quite rare outside the intense traffic corridors.

4. Depends entirely on the weather.

Sigh. Now I knew that you have absolutely no idea about nuclear weaponry.

Watch this:

This is a footage of AIR-2 Genie nuclear air-to-air rocket (not missile; it was unguided), airburst in 1957 live test. The 2-kt weapon was detonated on roughly 5600-6000 meters altitude, exactly over the group of observers, which stand directly under explosion.

No one of them was harmed. The dose of radiation they received was negligible.

There is NO fallout from altitude bursts. The fallout is a result of matter from surface being drawn into a fireball, irradiated, and them sucked upward into atmosphere with hot air current. But if fireball did not have contact with surface, the only matter in contact with fireball is the missile itself. Which is a Really Tiny Mass, that simply could not provide enough matter for irradiation - regardless of weather!

1. If you wish to return to a mid-70s ABM system.

2. Of course.

3. And how can you guarantee what route a HGV will use?

4. Of course. Yes, let's go back to 1950's health and safety standards.

So, in summary, you want a 1970's ABM system with 1950's health and safety standards. May I recommend this as the operator interface:

 

[Forest Green]

P.S. There is one alternative to nuclear SAM's that MAY be effective against HGV's. It is orbital laser array of megawatt-class, capable of burning through HGV heat protection.

The HGV's are more vulnerable to lasers than usual ballistic RV's. There are two reasons to that:

* HGV trajectory is partially-atmospheric, and they are subjected to rather high thermal loads while still on mid-course. While ballistic RV only subjected to high thermal load during the last phase of its flight.

* HGV could not be hidden in a cloud of decoys. To imitate the HGV flight, such decoys essentially must be a HGV's by themselves (which is not cost-effective). I.e. it could not hide in a cloud of cheap, numerous inflatable balloons, chaffs, ect.

So, if you have something like good ol' Zenith Star - more than one, actually - on orbit, you could stop HGV's without getting into nuclear area.

You would need a ridiculous number of Zenith Stars to be effective, the better solution is brilliant pebbles put into orbit using reusable LV technology. Hit the missile carrying the HGV before it is even deployed and potentially have more advanced glide KKV for intercepting the HGVs but if the HGVs fly high enough, standard KKVs may do. Sure the HGV can manoeuvre but it has no idea of when to manoeuvre. If you were to include laser-based defence, it should be a terminal ground-based defence, located around key targets. That way size, weight and hence power are not problems and they will always be in the correct place 24/7 and be far easier to maintain and much cheaper per shot than a nuke ABM. The HGV body will also be at its weakest in the terminal phase.

 

[Dilandu]

You would need a ridiculous number of Zenith Stars to be effective,

Actually no. We need only enough to cover the surface. And we could bring the required amount down a lot by using re-targeting sattelites (essentially a pair of mirrors that would catch the laser beam and re-focus it on target). Thing is, that while ballistic missile is generally vulnerable to Zenith Star only during the boost phase, the HGV is vulnerable during all its flight.

the better solution is brilliant pebbles put into orbit using reusable LV technology.

I'm not exactly sure. HTV is not boosting up as a ballistic missile - it's trajectory is much more flattened, and since it have a bit of maneuvering ability, it could boost not exactly at the target direction - and then use the atmosphere gliding to correct the trajectory. To intercept HGV, the orbiting kinetic interceptor would need quite a substantial amount of delta-V.

If you were to include laser-based defence, it should be a terminal ground-based defence, located around key targets.

Nah, I do not believe in atmospheric lasers. Vacuum lasers are much too simpler & way too effective. It would not be easy to burn down the HGV on terminal run - considering the plasma cocoon around it - but it would be quite easy to do that at mid-course.

 

[Dilandu]

1. If you wish to return to a mid-70s ABM system.

I wish to have a nuclear-tipped variant of SM-2ER missile on carrier escorts, and nuclear-tipped missiles for THAAD. This could be done with minimal refit. The SM-2ER missile have more than enough space & weight to put inside a kiloton-scale warhead.

3. And how can you guarantee what route a HGV will use?

I could not. But the probability that some unfortunate aircraft would be exactly in 1 km range of the interception point - i.e. that HGV, nuclear interceptor, and aircraft would converge exactly at the same spot of airspace at exactly the same time - is essentially nonexistent.

4. Of course. Yes, let's go back to 1950's health and safety standards.

Newsflash: if you are so concerned about safety standards, you hardly could fight a war at all.

Newsflash 2: the modern nukes are much more efficient than 1950s ones. They produce even less fallout (because the more fuel-efficient the bomb is, the less fissionable materials is left after blast)

So, in summary, you want a 1970's ABM system with 1950's health and safety standards. May I recommend this as the operator interface:

In summary, I want the system that would clearly work. While you are complaining that "maybe the enemy missile is actually loaded with butterflies and marshmallows" and "the risk that someone on the ground may be slightly harmed by defensive missile blast is totally unacceptable; better let them die under enemy missile strike".

 

[panzerfeist1]

Return Of The ABL? Missile Defense Agency Works On Laser Drone - Breaking Defense

HUNTSVILLE, ALA.: Three years after the Missile Defense Agency mothballed its massive Airborne Laser, MDA is planning to reboot the concept for a new era. The old ABL was Boeing 747 with a human crew and tanks of toxic chemicals to generate power. The new idea a high-altitude, long-endurance...

breakingdefense.com

"The old ABL was Boeing 747 with a human crew and tanks of toxic chemicals to generate power. The new idea a high-altitude, long-endurance drone armed with a more compact electrically powered laser. But the technical and tactical challenge remains the same: building a laser-armed aircraft that can shoot down ballistic missiles at their most vulnerable, just after launch, without having to fly so close it gets shot down itself.

The Missile Defense Agency is setting itself a higher bar than other military laser efforts. The Army, Air Force, and Navy have done “great work” on laser weapons for other missions, Syring said, but shooting down missiles in the boost phase requires much greater power, range, and beam quality. In fact, it may require higher performance than even the massive Airborne Laser managed.

In a successful 2010 test, ABL shot down a ballistic missile “tens of kilometers” away, Syring said, using about a megawatt of power. For the illustrative concept of operations the MDA director briefed at the conference — which he emphasized was not the only option — “we need to be hundreds of kilometers [from the target] in a platform that can go much higher and stay up for much longer.”

Best source I can find on laser capabilities at 1 megawatt, but it is against ballistic missiles that have not entered the re-entry phase but starting the boost phase.

 

[Forest Green]

You would need a ridiculous number of Zenith Stars to be effective,

Actually no. We need only enough to cover the surface. And we could bring the required amount down a lot by using re-targeting sattelites (essentially a pair of mirrors that would catch the laser beam and re-focus it on target). Thing is, that while ballistic missile is generally vulnerable to Zenith Star only during the boost phase, the HGV is vulnerable during all its flight.

the better solution is brilliant pebbles put into orbit using reusable LV technology.

I'm not exactly sure. HTV is not boosting up as a ballistic missile - it's trajectory is much more flattened, and since it have a bit of maneuvering ability, it could boost not exactly at the target direction - and then use the atmosphere gliding to correct the trajectory. To intercept HGV, the orbiting kinetic interceptor would need quite a substantial amount of delta-V.

If you were to include laser-based defence, it should be a terminal ground-based defence, located around key targets.

Nah, I do not believe in atmospheric lasers. Vacuum lasers are much too simpler & way too effective. It would not be easy to burn down the HGV on terminal run - considering the plasma cocoon around it - but it would be quite easy to do that at mid-course.

So the plasma cocoon doesn't affect the HGV during flight until the terminal phase? That's a heck of a lot of large objects in space, very costly, and those mirrors won't last one orbit with the amount of space crap floating around up there these days. Each mirrors will also have a power loss, the fuel for the laser will be limited, as will the power, 20MW absolute maximum based on a 100 ton craft. A ground-based laser could pump out hundreds of MW and be as big as you want.

The LV would still need to get high enough up to allow safe separation, i.e. near vacuum, so a KKV would still work, if not, a glide KKV.

The higher up, the lower the electrical resistance of air, and the more likely ionisation is. The missile body will be weakest in the terminal phase, and despite atmospheric attenuation, the laser will be closer and more powerful because it is much larger. Firing a laser between two different mediums also suffers refraction problems.

 

[Forest Green]

1. If you wish to return to a mid-70s ABM system.

I wish to have a nuclear-tipped variant of SM-2ER missile on carrier escorts, and nuclear-tipped missiles for THAAD. This could be done with minimal refit. The SM-2ER missile have more than enough space & weight to put inside a kiloton-scale warhead.

3. And how can you guarantee what route a HGV will use?

I could not. But the probability that some unfortunate aircraft would be exactly in 1 km range of the interception point - i.e. that HGV, nuclear interceptor, and aircraft would converge exactly at the same spot of airspace at exactly the same time - is essentially nonexistent.

4. Of course. Yes, let's go back to 1950's health and safety standards.

Newsflash: if you are so concerned about safety standards, you hardly could fight a war at all.

Newsflash 2: the modern nukes are much more efficient than 1950s ones. They produce even less fallout (because the more fuel-efficient the bomb is, the less fissionable materials is left after blast)

So, in summary, you want a 1970's ABM system with 1950's health and safety standards. May I recommend this as the operator interface:

In summary, I want the system that would clearly work. While you are complaining that "maybe the enemy missile is actually loaded with butterflies and marshmallows" and "the risk that someone on the ground may be slightly harmed by defensive missile blast is totally unacceptable; better let them die under enemy missile strike".

1. But not without significant cost.

3. Except there's likely to be more than one HGV and more than one aircraft.

4. I don't wish to see a return to open air nuclear testing thanks. And yes, you would need to test the missile.

Anyway, I'm done, this is too time-consuming.

 

[Dilandu]

So the plasma cocoon doesn't affect the HGV during flight until the terminal phase?

...From where it would came, when it is on high phase of trajectory?

That's a heck of a lot of large objects in space, very costly, and those mirrors won't last one orbit with the amount of space crap floating around up there these days.

Sigh. It seems that you do not understood orbital mechanics as well as nuclear physics.

To put it very-very simple: the space is big. Just the "low earth orbit" - generally assumed to be between 160 and 2000 km high - have a volume of freakin' 114.855.287 cubic kilometers.

The problem of orbital debris is essentially the problem of only most commonly used orbits - like geostationary - where the space is limited by ballistic. Most of the less used orbits are absolutely clean.

And since laser beam is not affected by orbital mechanics, the laser station did not need to be even close to those "commonly used" orbits. In could hung at, say, 5000 km altitude, without any problems at all.

Each mirrors will also have a power loss,

Yes. Not much a problem, since we could build quite good mirrors by now. Our orbital telescopes have excellent mirror capabilities.

A ground-based laser could pump out hundreds of MW and be as big as you want.

Yeah, yeah. It would be forced to fire through atmosphere fluctuations, it would have only a very short beaming time (because of a little thing known as "horizon" and "thickness of atmosphere on the beam path"), and it would be forced to fire at target exactly at the time when it is not particularly vulnerable.

The LV would still need to get high enough up to allow safe separation, i.e. near vacuum, so a KKV would still work, if not, a glide KKV.

...So you are suggesting to shot down HGV with essentially orbital-based HGV. Just great. There are enormous problems with building HGV projectile, and you are suggesting a HGV anti-projectile.

And those peoples are calling orbital laser "complicated"!

 

[Dilandu]

1. But not without significant cost.

The cost of nuclear warheads are not significant.

3. Except there's likely to be more than one HGV and more than one aircraft.

And so? How exactly it would change the situation?

4. I don't wish to see a return to open air nuclear testing thanks. And yes, you would need to test the missile.

...Why I need to live-test the nuclear-tipped missile? Or even the warhead, if I use a proven design (say, an adapted version of W80)?

Now I knew that you ability to analyze the situation is also deeply flawed. I have no reason to test the warhead on missile - I already knew that it would detonate (and even if I doubt that, I could just do underground test). All I need is to test the missile with the imitator of warhead in place, to make sure that it would fly without any unforeseen problems.

 

[Forest Green]

You hit the missile before it deploys the HGV. That's the point in having an orbital system. The glide vehicle is only needed if the LV missile doesn't get high enough to hit with a regular KKV. You hit the missile whilst it still has all it's warheads HGV, and is a slow, hot and large target.

As regards space-based lasers, ridiculously complicated. You won't be able to use reusable LVs for something that heavy and every mirror will incur a loss, as will charged particles in the magnetosphere. Excellent mirror capabilities when being heated by 20MW? None of this has even been done before.

The DoD has already been through these in a comprehensive feasibility study over 30 years ago and brilliant pebbles won.

If an enemy sends 1000 HGVs, are you going to detonate nuclear warheads in front of all of them in your own atmosphere?

You ignore questions you don't wish to answer, like the problem of firing a laser between two mediums, space to atmosphere. You still have to fire the laser through the atmosphere either way, because the HGV is in the atmosphere. We're talking about terminal defence for a ground-based laser, hence the distance would be small and the HGV would be more vulnerable after a long flight, when being heated by denser air.

Do some reading.

https://www.princeton.edu/~ota/disk3/1984/8410/8410.PDF

To yield diffraction-limited divergence, the mirror surface must be machined to within a fraction of a wavelength of its ideal design shape over its entire surface. Since the mirror is over a million wavelengths across, avoiding small figure errors is a severe requirement. A number of small mirrors can obviously combine to produce one large optical surface if their positions are all aligned to within a fraction of a wavelength. The 2 2 mirrors must maintain perfect surface shape in the face of heating from the laser beam, vibration from the chemical reaction powering the laser, and vibrations set up in the mirror as it is slewed. Substantial hardening of mirrors to radiation from nuclear bursts in space and to the xray laser (described below) would be a challenging task. The 2.5-meter diameter mirror on NASA’s Space Telescope was produced without these constraints.

 

[Desertfox]

Brilliant Pebbles will not work on a direct insertion HGV, they are also significantly more expensive than a nuclear-tipped interceptor and more strategically destabilizing as well.

 

[quellish]

There is NO fallout from altitude bursts. The fallout is a result of matter from surface being drawn into a fireball, irradiated, and them sucked upward into atmosphere with hot air current. But if fireball did not have contact with surface, the only matter in contact with fireball is the missile itself. Which is a Really Tiny Mass, that simply could not provide enough matter for irradiation - regardless of weather!

Fallout is bomb material, fission products, and whatever else is around at the time of detonation. Detonate on the ground, lots of stuff around (which bomb material, etc. mixes with). Detonate in the air, less stuff around. But there is still fallout.