Evolution of Pakistan's tactical nukes

[The Deterrent]

Recently, reports have emerged of a high powered electromagnetic rail gun developed by the Chinese. If Nasr's tactical warhead is propelled using such a railgun, it would increase its efficacy because:

1. The tell tale signature of ballistic missile launch would be removed.

2. Interception would be extremely difficult because the small warhead would be moving at a very high velocity.

You need to study how EM Rail Gun design works. The projectile itself is almost purely metallic in nature (kind of like a giant bullet) because large amounts of current has to pass through it. It intends to damage its target by its sheer kinetic energy.

You cannot place any explosive or combustible material in that projectile. Even if you could, the extremely high Gs wouldn't allow the electronics inside to function. Moreover the energy requirements for this kind of a land-based system are not feasible in a tactical environment.

 

[CriticalThought]

You need to study how EM Rail Gun design works. The projectile itself is almost purely metallic in nature (kind of like a giant bullet) because large amounts of current has to pass through it. It intends to damage its target by its sheer kinetic energy.

You cannot place any explosive or combustible material in that projectile. Even if you could, the extremely high Gs wouldn't allow the electronics inside to function. Moreover the energy requirements for this kind of a land-based system are not feasible in a tactical environment.

You need to study Faraday cage.

https://en.wikipedia.org/wiki/Faraday_cage

Effectiveness of shielding of a static electric field is largely independent of the geometry of the conductive material. However, static magnetic fields can penetrate the shield completely.

In the case of a varying electromagnetic fields, the faster the variations are (i.e., the higher the frequencies), the better the material resists magnetic field penetration. In this case the shielding also depends on the electrical conductivity, the magnetic properties of the conductive materials used in the cages, as well as their thicknesses.

A good idea of the effectiveness of a Faraday shield can be obtained from considerations of skin depth. With skin depth, the current flowing is mostly in the surface, and decays exponentially with depth through the material. Because a Faraday shield has finite thickness, this determines how well the shield works; a thicker shield can attenuate electromagnetic fields better, and to a lower frequency.

 

[The Deterrent]

You need to study Faraday cage.

https://en.wikipedia.org/wiki/Faraday_cage

What does the EM rail gun have to do with Faraday's Cage?

 

[CriticalThought]

What does the EM rail gun have to do with Faraday's Cage?

The warhead should be encased within a Farady cage to protect from the high EM interference.

 

[The Deterrent]

The warhead should be encased within a Farady cage to protect from the high EM interference.

EM interference is the last thing to worry about for a railgun projectile.

 

[CriticalThought]

EM interference is the last thing to worry about for a railgun projectile.

I am only responding to your post. You seem to be implying that the reason why no explosive or combustible material can be placed within the projectile is the large current passing through it.

You need to study how EM Rail Gun design works. The projectile itself is almost purely metallic in nature (kind of like a giant bullet) because large amounts of current has to pass through it. It intends to damage its target by its sheer kinetic energy.

You cannot place any explosive or combustible material in that projectile.

 

[The Deterrent]

I am only responding to your post. You seem to be implying that the reason why no explosive or combustible material can be placed within the projectile is the large current passing through it.

Um thats why you have been recommended to read how it works. Currently, a metallic slug is used as a projectile because the force is generated by the current passing through the arms of the gun and the projectile. You can't put anything inside it because it will limit the current & the heat generated will cause anything explosive to explode.

Now a metallic armature can be used instead to push a non-metallic projectile, but again the issues of high-Gs and power supply remain. EMW/EMP-protection (the purpose of Faraday's Cage) comes much later.

 

[CriticalThought]

Um thats why you have been recommended to read how it works. Currently, a metallic slug is used as a projectile because the force is generated by the current passing through the arms of the gun and the projectile. You can't put anything inside it because it will limit the current & the heat generated will cause anything explosive to explode.

Now a metallic armature can be used instead to push a non-metallic projectile, but again the issues of high-Gs and power supply remain. EMW/EMP-protection (the purpose of Faraday's Cage) comes much later.

So you mean ballistic missile warheads moving at extremely high Gs in terminal phase do not use electronics? They cannot be protected from high heat? Doesn't make any sense.

By the way, I know very well how an EM rail gun works. Thanks.

 

[The Deterrent]

So you mean ballistic missile warheads moving at extremely high Gs in terminal phase do not use electronics? They cannot be protected from high heat? Doesn't make any sense.

First, ballistic missiles face very little deceleration Gs (<30G for ICBMs, <15G for human carrying vehicles) during re-entry. That aside, the accelerations in such a rail-gun are thousands of times higher. For comparison, an artillery shell faces 15000 Gs, and lands a projectile roughly a mere 50km away.

The high heat is not generated because of the atmosphere, its because of the resistance (of the metal of the projectile) against the current.

By the way, I know very well how an EM rail gun works. Thanks.

Oh yeah, totally.
Instead of getting offended, try accepting and learning what you don't know.

 

[CriticalThought]

First, ballistic missiles face very little deceleration Gs (<30G for ICBMs, <15G for human carrying vehicles) during re-entry. That aside, the accelerations in such a rail-gun are thousands of times higher. For comparison, an artillery shell faces 15000 Gs, and lands a projectile roughly a mere 50km away.

And it is certainly not an unsurmountable problem. Per post by @The SC above, nuclear artillery has been developed previously. Similar techniques can be applied for the railgun as well. For example, refer to the attached which is downloaded from

http://dtic.mil/cgi-bin/GetTRDoc?AD=ADA443252

The high heat is not generated because of the atmosphere, its because of the resistance (of the metal of the projectile) against the current.

However it is generated, the outer metallic covering can be considered a skin and insulation can be applied beneath it.

Oh yeah, totally.
Instead of getting offended, try accepting and learning what you don't know.

[/QUOTE]

Sorry, but you have not taught me anything about railguns that I didn't previously know. I did get new knowledge about the kinds of G forces faced by artillery shells. Thanks for that.

If you re-read my posts, I have said that research and development would be needed to make this possible. But you seem intent on proving that it is not possible by bringing up problems which can be resolved by appropriate R&D.

 

[The Deterrent]

And it is certainly not an unsurmountable problem. Per post by @The SC above, nuclear artillery has been developed previously. Similar techniques can be applied for the railgun as well. For example, refer to the attached which is downloaded from

http://dtic.mil/cgi-bin/GetTRDoc?AD=ADA443252

Keep in mind that the present rail-gun design is intended for ~350km range. The G forces increase similarly in proportion.

If you re-read my posts, I have said that research and development would be needed to make this possible. But you seem intent on proving that it is not possible by bringing up problems which can be resolved by appropriate R&D.

Why go for such an expensive solution when even a 203mm or 155mm artillery can do the job (for lesser ranges)? Indian BMD is not effective against salvos, particularly up till the strike range of Nasr. It can be easily outnumbered or outmaneuvered.

As far as railgun based nukes are concerned, are they possible to make? Probably (by US/PRC). Are they feasible?
Absolutely not.

 

[CriticalThought]

Keep in mind that the present rail-gun design is intended for ~350km range. The G forces increase similarly in proportion.


Why go for such an expensive solution when even a 203mm or 155mm artillery can do the job (for lesser ranges)? Indian BMD is not effective against salvos, particularly up till the strike range of Nasr. It can be easily outnumbered or outmaneuvered.

As far as railgun based nukes are concerned, are they possible to make? Probably (by US/PRC). Are they feasible?
Absolutely not.

Recently, there was a thread on fire control radars and how they could be used to track where artillery fire comes from. The high speeds of a rail gun projectile woukd make it harder for such radars to track it also.

What's your computation that shows the infeasability of rail gun nukes?

 

[SQ8]

Recently, there was a thread on fire control radars and how they could be used to track where artillery fire comes from. The high speeds of a rail gun projectile woukd make it harder for such radars to track it also.

What's your computation that shows the infeasability of rail gun nukes?

Essentially all nukes will have to be extremely tolerant

The HVP is an interesting project to read up on
https://fas.org/sgp/crs/weapons/R44175.pdf

 

[The Deterrent]

Recently, there was a thread on fire control radars and how they could be used to track where artillery fire comes from. The high speeds of a rail gun projectile would make it harder for such radars to track it also.

What's your computation that shows the infeasability of rail gun nukes?

Agreed, it would be harder for counter-artillery radars to track Mach 5-7 projectiles.

This is the figurative representation of the present BAE Systems' EMRG:

Further details: http://www.navweaps.com/Weapons/WNUS_Rail_Gun.php

Coming to why 'nuclear' EMRG is infeasible, specifically for a country like Pakistan:

1. Projectile's Physical Packaging: To-date, there have been no demands by the militaries of US/PRC of an explosive charge aboard such a projectile, as the kinetic energy of the projectile is enough to damage/destroy the relevant intended targets. Assuming such a requirement does arise, and that too nuclear in nature, it will be extremely difficult to design such a projectile. Taking the smallest 155mm tactical nuke as an example, it would require a reasonably large projectile (250-300mm) to house such a package. This further increases the size of the launch vehicle, way beyond tactical mobility parameters.

2. Projectile Electronics: Inability to develop expensive extremely high-G ( > 50,000Gs, reference: General Atomics' Blitzer's 60,000Gs) resistant electronics. Procurement is questionable, since this kind of equipment is currently under-development by the leading military R&D giants (US & PRC). The US Navy issued the following requirements for the electronics package of such a projectile in 2012:

The package must fit within the mass (< 2 kg), diameter (< 40 mm outer diameter), and volume (200 cm3) constraints of the projectile and do so without altering the center of gravity. It should also be able to survive accelerations of at least 20,000 g (threshold) / 40,000 g (objective) in all axes, high electromagnetic fields (E > 5,000 V/m, B > 2 T), and surface temperatures of > 800 deg C. The package should be able to operate in the presence of any plasma that may form in the bore or at the muzzle exit and must also be radiation hardened due to exo-atmospheric flight. Total power consumption must be less than 8 watts (threshold) / 5 watts (objective) and the battery life must be at least 5 minutes (from initial launch) to enable operation during the entire engagement. In order to be affordable, the production cost per projectile must be as low as possible, with a goal of less than $1,000 per unit.

3. Power Supply Issues: The EMRG prototypes currently under development are housed aboard naval vessels, having large enough power supply (reference: DDG-1000 USS Zumwalt's 80mW). The weapon prototype itself requires 15-30mW of power in addition to massive capacitor banks. Supplying a tactical, 'mobile' (shoot-n-scoot?) system with such amounts of electrical resources severally hinders its effectiveness.

4. Mobility Constraints: Extending point 1 & 3, the size of such a system would be too big to be effective for its intended purpose. Compare with the present 155mm EMRG prototype with HVP inert projectile (note: the barrel length is 10m)

Now, coming to why such a 'nuclear' EMRG is impractical, specifically for a country like Pakistan:

1. Design and development of such a complex system, from scratch, considering the technical capabilities of Pakistan as a 3rd world country...is a fanboy's dream. Bear in mind that the system under-consideration would need a ~300mm calibre
2. The financial resources required for such a system beyond Pakistan's reach.
3. The velocity advantage (Mach 7 for a ~160km range system) is questionably low, since the existing Nasr missile already has a maximum velocity of Mach 3-4 (reference: typical MBRLs have ~Mach 3 maximum velocity).
4. The mobility disadvantage is high and renders such a system ineffective for its intended use by Pakistan.
5. The only argument favoring such a EMRG-based tactical nuke is the interception of Nasr missiles, which can be avoided by simply saturating the BMD (IF ANY) by using low-cost MBRLs or non-nuclear Nasrs.

In short, ham se na ho paey ga.

 

[CriticalThought]

Agreed, it would be harder for counter-artillery radars to track Mach 5-7 projectiles.

This is the figurative representation of the present BAE Systems' EMRG:
View attachment 391944
Further details: http://www.navweaps.com/Weapons/WNUS_Rail_Gun.php

Coming to why 'nuclear' EMRG is infeasible, specifically for a country like Pakistan:

1. Projectile's Physical Packaging: To-date, there have been no demands by the militaries of US/PRC of an explosive charge aboard such a projectile, as the kinetic energy of the projectile is enough to damage/destroy the relevant intended targets. Assuming such a requirement does arise, and that too nuclear in nature, it will be extremely difficult to design such a projectile. Taking the smallest 155mm tactical nuke as an example, it would require a reasonably large projectile (250-300mm) to house such a package. This further increases the size of the launch vehicle, way beyond tactical mobility parameters.

2. Projectile Electronics: Inability to develop expensive extremely high-G ( > 50,000Gs, reference: General Atomics' Blitzer's 60,000Gs) resistant electronics. Procurement is questionable, since this kind of equipment is currently under-development by the leading military R&D giants (US & PRC). The US Navy issued the following requirements for the electronics package of such a projectile in 2012:


3. Power Supply Issues: The EMRG prototypes currently under development are housed aboard naval vessels, having large enough power supply (reference: DDG-1000 USS Zumwalt's 80mW). The weapon prototype itself requires 15-30mW of power in addition to massive capacitor banks. Supplying a tactical, 'mobile' (shoot-n-scoot?) system with such amounts of electrical resources severally hinders its effectiveness.

4. Mobility Constraints: Extending point 1 & 3, the size of such a system would be too big to be effective for its intended purpose. Compare with the present 155mm EMRG prototype with HVP inert projectile (note: the barrel length is 10m)

Now, coming to why such a 'nuclear' EMRG is impractical, specifically for a country like Pakistan:

1. Design and development of such a complex system, from scratch, considering the technical capabilities of Pakistan as a 3rd world country...is a fanboy's dream. Bear in mind that the system under-consideration would need a ~300mm calibre
2. The financial resources required for such a system beyond Pakistan's reach.
3. The velocity advantage (Mach 7 for a ~160km range system) is questionably low, since the existing Nasr missile already has a maximum velocity of Mach 3-4 (reference: typical MBRLs have ~Mach 3 maximum velocity).
4. The mobility disadvantage is high and renders such a system ineffective for its intended use by Pakistan.
5. The only argument favoring such a EMRG-based tactical nuke is the interception of Nasr missiles, which can be avoided by simply saturating the BMD (IF ANY) by using low-cost MBRLs or non-nuclear Nasrs.

In short, ham se na ho paey ga.

It's a bit far fetched, but nuclear detonation is triggered through:

1. Explosion that reduces volume, thus concentrating neutron production causing chain reaction.
2. Introduction of neutron source that provides a deluge of neutrons.

In order to circumvent the problems with electronics:

a. Delayed fuses could be used. These would be materially delayed rather than electronically delayed, set to reach full explosion after a given amount of time.
b. Delayed mechanical injection of neutron source.

Basically, if electronics is a problem, then mechanics should be considered.

I have seen videos of a Turkish rail gun and size doesn't seem to be a problem.

An increase of approx. 100% over Nasr is definitely significant.