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Balakot air strike: Why IAF used 907-kg ‘penetrator’ bombs to target Jaish terror camp

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Balakot air strike: Why IAF used 907-kg ‘penetrator’ bombs to target Jaish terror camp
The Israeli SPICE 2000 used by IAF has an advanced electrical fuze, which accurately predicts the impact sequence and delay required to activate.
SAMEER JOSHI
13 March, 2019 5:33 pm

Illustration by ThePrint Team

At around 3.30 am on 26 February, Mirage 2000s of the Indian Air Force made shallow incursions inside Pakistan and targeted Jaish-e-Mohammed camps at Balakot, along with Muzaffarabad and Chakothi (in Pakistan Occupied Kashmir). The strike on the Markaz Syed Ahmad Shaheed madrasa complex located on Jaba hill-top in Balakot was the most significant amongst them, especially considering that the Indian Air Force had struck a target inside Pakistan for the first time since the 1971 war. The strikes were a direct response to the attack by the Pakistan-based terror proxy – JeM – on a CRPF convoy at Pulwama on 14 February in which over 40 Indian jawans had lost their lives.

The IAF used the Israeli made SPICE 2000 stand-off glide bomb to target Balakot. The SPICE 2000 is a glide bomb kit, fitted on a 2000 lb (907 kg) bomb. The IAF uses both the SPICE 1000 and 2000 kits. As per Indian Air Force sources, 5 x SPICE 2000s were utilised to target Balakot, while one bomb was brought back. These bombs fell within 2 metres of their designated mean points of impact (DMPI) in the targeted area. The Indian Air Force has publicly stated that it has synthetic image radar (SAR) imagery of the post-strike battle damage analysis, which confirms its claim that all targets were accurately hit.

Location of JeM’s Balakot terror training camp on Google Maps | Sameer Joshi
Meanwhile, Pakistan has denied any damage or casualties at Balakot, and said that the Indian payloads landed in the nearby forest, missing the targets completely. International satellite experts based on their reading of data available with private satellite networks post-strike, have ridiculed Indian claims that the bombs fell anywhere on the target. This has been widely supported by a large section of the western media, who have been sceptical about the accuracy of the attack. Pakistan, on its part, has completely sealed the targeted camp in Balakot, discouraging any independent verification of the damage.

What has baffled the world is why the 2000 lb bombs, which hit the madrassa complex, did not cause widespread explosive damage over the target. George William Herbert, an international weapon’s expert, tweeted a few days ago that a 2000 lb/907 kg bomb like the Mk 84 made of 428 kg trinitol high explosive core and a 479 kg of metal casing, would have obliterated the building, destroying it completely due to the shock wave travelling at over 1.83–2.13 km/s. Typically, it would double the pressure inside a standard three-storey building around 25 meters wide, further contributing to the damage.

Also read: Pakistan’s entire navy has been out at sea after India bombed Balakot

Latest OSINT data reveals that while at least two of the targeted structures are still standing – with dark smudges or holes visible on the rooftop of the biggest target — they also suggest that SPICE bombs have indeed penetrated the building. While the imagery is synonymous with SPICE strikes seen in Syria, this does not match up to the damage assessment for an Mk 84 or an equivalent bomb carried as part of the SPICE 2000 glide kit as brought out by George Herbert. Also, suspected use of Fuel Air Explosive (FAE) through the SPICE 2000 mission, supported by dark smudges seen in the target area imagery, is also seen as a possibility by some experts. In addition, there is indication of a deep penetration SPICE bomb hit north of the big hall, where a seeming heap of soil is present, which suggests that either the building collapsed after being targetted or the Pak Army has razed it to the ground post strike to hide the damage.

Post Strike Analysis of the target | Col Vinayak Bhatt | ThePrint
Also read: First satellite images show likely damage to Jaish Balakot camp but no massive destruction

IAF sources have recently confirmed that the Mirages had used the ‘penetrator’ version of the SPICE 2000 glide bomb, which has a 907 kg hard metal reinforced casing with an embedded ‘low mass’ TNT warhead of 70–80 kg of net explosive quantity (NEQ). This version is designed to target reinforced concrete installations like C2 centres, penetrating deep before carrying out a low mass explosion to eliminate all with shrapnel and a blast over pressure wave, and not necessarily collapsing the targeted installation. The IAF is confident that this is what has happened at Balakot. This theory is reinforced by the statement of Maulana Ammar, the younger brother of the JeM boss Masood Azhar, that the madrassa complex at Jabba top has indeed been hit by Indian bombs; as well as through discreet interviews with eyewitnesses in the area amid a media clampdown by the Pakistani army, which confirms witnessing at least 35 bodies of killed JeM militants and ISI operatives being taken out post-strike. Indian intelligence had estimated more than 250-300 individuals active inside the camp before the strike. Details of actual number of casualties remains sceptical as of now.

However, rather than being taken at a face value, this revelation has been further given an unwarranted spin within the media and intersecting theories. This is because even a 70–80 kg low mass TNT explosion would send shrapnel and corresponding shock waves upward of 1 km/s as dictated by the Gurney equation out to around 14 meters, enough to cause very significant damage to the targeted structure. Let’s hence diagnostically analyse the usefulness of the penetrator version of the SPICE 2000 as the bomb used by the IAF in its strike at Balakot.

The right deal for the job at hand?
The weapon to target matching suggests that the IAF was specifically looking to carry out a precision strikes and avoid large area collateral damage. As described after strike by the Indian Foreign Secretary, the ‘non-military preemptive strikes’ was aimed at targeting the JeM cadre while avoiding civilian and Pakistani military casualties. Hence the ‘penetrator’ version of the Spice 2000, with a low mass TNT warhead was the right fit for the mission as compared to the high mass Mk 84 bomb equivalent version, which would have inflicted significantly more area damage. The SPICE 2000 is an all-weather 1000 kg glide bomb kit, which uses 12 control surfaces to achieve a definitive range of 60 kilometres. It navigates with the help of IN/ GPS and approaching the target reduces the GPS errors using its electro optical/ infra-red terminal attack sensor. This matches what it sees with pre-loaded satellite/ drone imagery of the target through ‘scene matching’, rapidly reducing the margin of errors and impacting the target within a CEP of less than 3 meters.

Also read: BJP’s backroom warriors are realising they can’t bank on Balakot and are changing gears

The SPICE 2000 used by the IAF has an advanced electrical fuze, which accurately predicts the impact sequence and delay required to activate. This is especially useful when penetrating multiple floors of a building, before exploding on the right level. A microphone embedded with a microcontroller in the smart fuze is used, with the microphone measuring the number of impacts and the microcontroller counting the floors, until the bomb breaks through the desired number of floors. Used extensively by the Israeli Air Force in Lebanon and Syria against tactical battlefield targets and in urban areas, the SPICE 2000 has a near perfect operational reliability record. These fuses would be critical in penetrating the various targeted buildings with at least 2 levels.

The focus of SPICE 2000 strike was the madrasa complex at the north edge of Jaba top, dominated by a huge 30 meters (length) x 30 meters (width) x 8 meters (max height) white/gray main Madrassa building, used mostly for imparting lessons by the instructors to their trainees. This would possibly be the target for a solitary Spice 2000 bomb. Connected to this main hall is a set of buildings. Another concrete structure with two storeys 12 meters (length) x 10 meters (width) x 8 meters (height) is located to the north of the big hall, which housed the under-training ab-initio cadre of the JeM. This building would have been targeted with a SPICE 2000 bomb. There was a twin storey mosque to the right of this building and a shed further to the north. To the south of the big hall, across the training ground was a robust ‘U’ shaped concrete structure with sloped roof, housing the instructors, senior trainees and a guest house in each component. One SPICE 2000 bomb each, would certainly have been earmarked for the Guest House, the Instructor’s quarter and the senior trainee accommodation. The last target was the house of Umar Ghouri, the local JeM boss, who lived across the dirt track. This would be a certain target for a single SPICE 2000 bomb. It is believed that one of the SPICE 2000s malfunctioned and could not be launched by the Mirage 2000s. Hence in all probability, one of the targets out of the GH, instructors and senior trainee buildings would not have been engaged.

Pre-strike vintage images of the buildings show thin metal roofs, with light concrete layer and two storeys. The walls would be a mix of concrete, local bricks and mortar, reinforced by rough iron pillars and concrete for support as is common in the construction characteristics found in Balakot region. While viewing historic satellite imagery of the place, it’s interesting to note the camp mostly survived the 2005 Balakot earthquake which caused widespread devastation in the area.

Possible targets for IAF in the JeM Camp | Sameer Joshi
Post-strike imagery analysis done from the images available, has revealed that all the bombs impacted the roofs of the various targets at near vertical position. This would have been tactically planned by the IAF to achieve maximum penetration, before the bombs exploded. This may also explain the reason behind the IAF’s shallow incursions in Pakistan Occupied Kashmir, aiming to fire the SPICE 2000 well within its launch envelope to achieve the optimal vertical trajectory over the target, rather than launch it at the fringe range of 60 kilometres from Indian territory.

To be or not to be…
Let’s analyse the science of what happened post impact on 26 February at Jabba top, Balakot. If we compare the Israeli made SPICE 2000’s penetrator casing volume and weight; it is closest to the USAF’s BLU 116 penetrator used on the GBU 24/27 series 2000 lb bunker busting munition. As per information, the BLU 116 can penetrate 3.4 meters of reinforced steel (or 15 meters of earth) using a nickel cobalt steel alloy core. The Spice 2000 penetrator bomb has similar capabilities. Assuming that the SPICE 2000 hit the target at a near nadir point, it would have easily sliced through the thin metal/ light concrete roof and at least one semi concrete floor to hit the base floor with a decent foundation in the ground, which is largely made up of Bafliaz volcanic rock in the Balakot region. For the sake of calculating the impact force on a bunker class target, we will assume the SPICE 2000 is able to penetrate at least 3 meters of 500 PSI reinforced concrete (a figure which is certainly less than the actual) and 10m of earth.

We reverse calculate the average impact force on a reinforced concrete target as follows –

Average impact force = mgh ÷ d
m — Weight of the penetrator (907 kg)
g — Acceleration due to gravity (9.81 m/s)
h — AGL height where the bomb transitioned from glide mode to vertical drop trajectory (a minimal 500 metres estimated for the Balakot attack)
d — Depth of penetration

Therefore, Average impact force of SPICE 2000 on reinforced concrete is 1474 kN and on earth is 442 kN. Incidentally, the more a bomb penetrates into the ground, the lesser will be its average impact force. The Bafliaz volcanic rock at Balakot is composed of at least three quarters of alkaline basalt, which has a density of 2.8 g/cm3. The approximate density value for 500 PSI reinforced concrete is 2.9 g/ cm3, which is close to basalt. Taking the margins in error and chemistry of basalt, it can safely be assumed that after penetrating the roof and another possible floor, the impact value would have increased from the 442 kN on the roof and the first level to (taking an approx. 15 percent jump within margin of error) to 508 kN. However, with the penetrator intact and no major loss in momentum, the same 15 % error margin can be applied to the 1474 kN standard 500 PSI reinforced concrete penetration figure, this time reducing the average impact force to 1253 kN, giving us a penetration distance of 3.5 meters in the Bafliaz rock geology at Jaba top.

The SPICE 2000 flight profile and penetration into the rocky surface explained | Sameer Joshi
The smart fuze of the SPICE 2000 would have been set to explode after penetrating two layers as per the intelligence available before the strike. After digging deep 3.5 meters below the big hall, it would have triggered the explosion of 80 kilograms of TNT, with the Gurney equation estimating shrapnel release at nearly 1 km/ sec for an explosive equivalent of the TNT. At the same time, the expansion of the intensely hot gases at extremely high pressures in the fireball would have caused a shock wave to form, moving upward out of the dug in silo at nearly the same velocity out to an effective range of 14 meters. The main characteristic of this wave is that the pressure rises very sharply at the moving front, and falls off toward the interior region of the explosion. The variation of the pressure with distance from the centre of the fireball, at a given instant, is ideal for (instantaneously rising) shock front, which will eliminate any soft target in the region and cause significant damage to the structure and depending on the distance, will cause the structure to collapse.

Now let’s calculate the overpressure caused by the explosion of the 80 kg warhead — Overpressure in an enclosed space is determined using Weibull’s formula –

Overpressure Δp=2410(m/V) to the power 0.72 where: 2410 is a constant based on 1 bar (100 kPa; 15 psi); M = Net explosive mass calculated using all explosive materials and their relative effectiveness; V = Volume of given area (primarily used to determine volume within an enclosed space).

We have two zones to measure the overpressure, the first inside the 3.5 m silo created by the SPICE 2000 penetrator. This gives us a value of approx. 12631 kPA for the overpressure wave within the dug-up silo. This overpressure wave would have resonated through the rocky side, ejecting upward at a high velocity towards the single/ twin floors of the targets. Post expansion, the shrapnel and the overpressure wave would have killed all soft tissue targets and penetrated the walls and roofs with deadly effect.

But was that enough to collapse the buildings? As per experimental data, a minimal overpressure of around 14 kPA is required to cause the collapse of a non-concrete structure. Since the volume of the building was very large with two floors inside the building, the overpressure blast wave from the 80 TNT kg warhead, had it exploded at the base of the building (not accounting for the penetration to 3.5 meters), would be in the tune of 19.28 kPA. This overpressure would probably have brought down the buildings to implode and collapse. However, the explosion of the warhead 3.5 meters below the surface, with the rocky sides, walls bearing partial explosion and blast overpressure effects; will significantly drop the overpressure value inside the compartmentalised hall. What would also be noteworthy is that the foundation and support beams would have been dug in the solid basalt rock, hence will require a significantly greater charge to knock down core load bearing members, than the low mass 80 kg TNT of the penetrator version.

Also read: What Pulwama-Balakot proves: A ‘third’ actor can still push India and Pakistan into a war

Though not basing assumptions on an empirical relationship and keeping well within the error margin, it can safely be assumed that the value of the blast overpressure wave would have fallen far below 14 kPA, which — while causing extensive kinetic energy based shrapnel and overpressure pressure damage to the roof and the sides, would not have been sufficient to break open or collapse the side walls with intermixed concrete, and the main roofs of the building. Compartmentalised damage would have occurred in the individual bomb’s sphere of influence.

Yes, there would be significant casualties within the confines of the targets due to shrapnel, intense heat and overpressure waves.

One piece of the puzzle is still not clear: why are multiple entry points visible on the roof of the big hall, when the building may have been targeted only by a single SPICE 2000 as per the data available on the number of bombs and the speculated targets? In all probability, these would be the result of inside to outside blast incursions.

One can, however, clearly see the result of the attack on the trainee accommodation north of the main hall (Refer Target 1), where the building has been destroyed with deep ingestion marks and a lot of loose soil unearthed, the classic tell-tale signs of a penetrator warhead entering the ground and making a mould of earth around it. This indicates that there was more sub soil present than basalt rock, underneath the structure as mentioned or a cover-up operation underway by the Pakistani Army post blast. Since the IAF points out that all the SPICE 2000 bombs hit within the CEP, impact points on the other targets would indicate clean penetration and deep explosions, which while killing all, would not be sufficient to get the complete buildings down as is seen at other locations.

Possible Target Post Strike Analysis by the author. Image courtesy Planet Earth Labs
Did the IAF SPICE 2000s strike at the target ?  Yes, they did. This assessment is based on the science of it all, which can be debated by explosive experts for its worth. The Indian Air Force has done its job; let’s not overreact to anything and everything of it. One day we will know what happened below that roof.

So, when the Indian Air Chief says ‘We hit the targets’, believe me, he means serious business!

The author is an former fighter pilot with extensive experience on the Mirage 2000 and MiG 21 aircraft of the IAF.

This article was first published on Medium.

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Tags: Balakot air strikesIndia-Pakistan relationsIndian Air ForceMirage 2000Pulwama attack
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View Comments




    • Khan :
      13 March, 2019 at 6:17 pm
      Oh my God.
      Well... I am really happy to read all bogus and propaganda articles in Indian media, all most all paid by BJP & their supporter. But that’s good sign, how Indian manipulating their own people. I am shocked to see how famous name of India journalism, all are part of this propaganda paid by ruling party.

      All these articles, of course help to get BJP more vote (that’s the main goal right now) but for international community, they want hard core proof & evidence, which don’t exists.

      Keep the propaganda and get more vote for BJP and get more advertisement & money ;-)
    • Jerry :
      14 March, 2019 at 6:56 pm
      It is amazing to read how advanced warfare has gone in terms of scientific innovation. Proves the point when the External Ministry Spokesperson mentions that it was targeted at Terrorist infrastructure.
      For a pakistani this might be a fiction out of an Issac Assimov novel and rightly so. In a country where science books are all about Thr Supreme Lord and perhaps science at best means suicide belt and phd in science means someone who wears it and blows himself, such a frustration is understandable Mr. Khan.
      The truth about all the previous wars including Kargil have been told by some of the sensible journalists and surprisingly Army generals, so give this also some time and truth will come out.
      In India, we bow before our armed forces because of RESPECT and not FEAR( unlike with our neighbours).
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Nice novel
 

The Deterrent

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@The Deterrent .A good read .
Perhaps you can criticise this one
Cross posting:



Latest OSINT data reveals that while the targeted structure is still standing, dark smudges or holes are visible on the rooftop, suggesting that SPICE bombs may have penetrated inside the building and gone deep inside the earth, before destroying all in a confined explosion.

Here's where the whole hole theory (no pun intended) began: Twitter user @rajfortseven, the retd. Col. Vinayak Bhatt of the IA. He posts his personal IMINT analysis, which has not been always correct (if anybody is interested, I can refer them to some tweets and why he was wrong there). The resolution of the PlanetLabs imagery is about 72 cm, and as the author rightly points out, we see SMUDGES. If anbody would care to look at the historical Google Earth imagery of the structure, they would realize that similar smudges have been on the roof of the structure in the past as well, in different locations. The most likely explanation for the smudges is the different nature of the CGI sheets used on the roof, probably due to repairs over the years. They might as well be tree branches broken off by high winds.

We now have 50 cm resolution satellite imagery from European Space Imaging, showing no signs of damage, captured on February 27th, 5 days before the date of the PlanetLabs imagery which was captured on March 4th. This imagery shows no visible holes or damage to the structure's roof. In all probability, Col. Bhat erred in his analysis and the low resolution combined with dark smudges gave him this idea. It is important to realize that the holes theory is the foundation of the entire argument.
https://www.euspaceimaging.com/paki...ms-india-missed-target-in-pakistan-airstrike/

Besides, Col. Bhatt concluded that SPICE-250s, not SPICE-2000s, were used in the strike. So which version is true?


IAF sources have recently revealed that the Mirages had used the ‘penetrator’ version of the SPICE 2000 glide bomb, which has a 907 kg hard metal reinforced casing with an embedded ‘low mass’ TNT warhead of 70–80 kg of net explosive quantity (NEQ). This version is designed to target reinforced concrete installations like C2 centres, penetrating deep before carrying out a low mass explosion to eliminate all with shrapnel and a blast over pressure wave, and not necessarily collapsing the targeted installation.
There are two problems with the penetrator theory:

1. There is no indication of presence of any penetrator like that in IAF's service.

2. The said target did not require the use of a penetrator warhead. A "floor counting" fuse attached to a general purpose bomb would've achieved the required results. It is very hard to believe that a civilian structure at Balakot was in fact a bunker (built probably in the late 90s), the kind only found in military bases for the high command, considering that the location is neither an active war zone nor a military base.

The IAF is confident that this is what has happened at Balakot. This theory is reinforced by the statement of Maulana Ammar, the younger brother of the JEM boss Masood Azhar, that the madrassa complex at Jabba top has indeed been hit by Indian bombs; as well as through discreet interviews with eyewitness in the area amid a media clampdown by the Pak army, who confirm witnessing at least 35 bodies of killed JEM militants and ISI operatives being taken out post-strike. Indian intelligence had estimated more than 250 -300 individual active inside the camp before the strike. Details of actual number of casualties remains sceptical as of now.
There is no credible, irrefutable evidence of any kind of human loss in the attack. So, far, all claims have been conjecture (questionable audio and video clips, report of one odd journalist). There is no need to elaborate more on that.

Precisely! And to add to that, the hole theory proposes 4x holes and hence 4x SPICE-2000 SOWs, i.e. 280-320 kg of combined total TNT inside the hypothetical bombs. This is NOT an insignificant amount.
Precisely! And to add to that, the hole theory proposes 4x holes and hence 4x SPICE-2000 SOWs, i.e. 280-320 kg of combined total TNT inside the hypothetical bombs. This is NOT an insignificant amount.

The SPICE 2000s used by the IAF has an advanced electrical fuze, which accurately predicts the impact sequence and delay required to activate. This is especially useful when penetrating multiple floors of a building, before exploding on the right level. A microphone embedded with a microcontroller in the smart fuze is used, with the microphone measuring the number of impacts and the microcontroller counting the floors, until the bomb breaks through the desired number of floors.
It is true that penetrator munitions work on this principle of combining estimated delay figures with smart features like microphones to detect number of penetrated floors. However, a SPICE-2000 kit (or any PGM kit) is DECOUPLED with the 2000lbs munition, as far as fuzing is concerned. The fuze of a penetrator munition is built into the casing, so that it can also survive the penetration shocks alongwith the explosive. This rules out the possibility that SPICE-2000 itself packs the sensors and fuzing mechanism for detonation.

What is also interesting to note is that many other structures also survived the 2005 earthquake. Were they all hardened bunkers as well, built for JeM's leadership?
What is also interesting to note is that many other structures also survived the 2005 earthquake. Were they all hardened bunkers as well, built for JeM's leadership?

Let’s analyse the science of what happened post impact on 26 February at Jabba top, Balakot. If we compare the Israeli made SPICE 2000’s penetrator casing volume and weight; it is closest to the USAF’s BLU 116 penetrator used on the GBU 24/27 series 2000 lb bunker busting munition.
This is a VERY MISLEADING comparison, specially because the entire henceforth article is based on the premise that the hypothetical 'penetrator bomb' (a 2000lbs munition used with the SPICE-2000 kit) had the characteristics of BLU-116. The BLU-116 Advanced Unitary Penetrator has 109 kg of explosive filling, SIGNIFICANTLY higher than the figure used in the later calculations (80 kg).

Regardless, is the author implying that US or Israel sold such a penetrator munition to IAF? When did this happen?
If not, did DRDO develop such a munition for IAF? When did this happen?

As per information, the BLU 116 can penetrate 3.4 meters of reinforced steel (or 15 meters of earth) using a nickel cobalt steel alloy core. The Spice 2000 penetrator bomb has similar capabilities. Assuming that the SPICE 2000 hit the target at a near nadir point, it would have easily sliced through the thin metal/ light concrete roof and at least one semi concrete floor to hit the base floor with a decent foundation in the ground, which is largely made up of Bafliaz volcanic rock in the Balakot region. For the sake of calculating the impact force on a bunker class target, we will assume the SPICE 2000 is able to penetrate at least 3 meters of 500 PSI reinforced concrete ( a figure which is certainly less than the actual) and 10m of earth. We reverse calculate the average impact force on a reinforced concrete target as follows –

Average impact force = mgh ÷d

m — Weight of the penetrator (907 kg)

g — Acceleration due to gravity (9.81 m/s)

h — AGL height where the bomb transitioned from glide mode to vertical drop trajectory ( a minimal 500 meters estimated for the Balakot attack)

d — Depth of penetration

Therefore, Average impact force of SPICE 2000 on reinforced concrete is 1474 kN and on earth is 442 kN. It is noteworthy that the more a bomb penetrates into the ground, the lesser will be its average impact force. The Bafliaz volcanic rock at Balakot is composed of at least three quarters of alkaline basalt, which has a density of 2.8 g/cm cube. The approximate density value for 500 PSI reinforced concrete is 2.9 g/ cm cube, which is close to basalt. Taking the margins in error and chemistry of basalt, it can safely be assumed that after penetrating the roof and another fpossible loor, the impact value would have increased from the 442 kN on the roof and the first level to (taking an approx. 15 percent jump within margin of error) to 508 kN. However with the penetrator intact and no major loss in momentum, the same 15 % error margin can be applied to the 1474 kN standard 500 PSI reinforced concrete penetration figure, this time reducing the average impact force to 1253 kN, giving us a penetration distance of 3.5 meters in the Bafliaz rock geology at Jaba top.




The smart fuze of the SPICE 2000 would have been set to explode after penetrating two layers as per the intelligence available before the strike. After digging deep 3.5 meters below the big hall, it would have triggered the explosion of 80 kilograms of TNT, with the Gurney equation estimating shrapnel release at nearly 1 km/ sec for an explosive equivalent of the TNT. At the same time, the expansion of the intensely hot gases at extremely high pressures in the fireball would have caused a shock wave to form, moving upward out of the dug in silo at nearly the same velocity out to an effective range of 14 meters. The main characteristic of this wave is that the pressure rises very sharply at the moving front, and falls off toward the interior region of the explosion. The variation of the pressure with distance from the centre of the fireball, at a given instant, is ideal for (instantaneously rising) shock front, which will eliminate any soft target in the region and cause significant damage to the structure and depending on the distance, will cause the structure to collapse.

Now let’s calculate the overpressure caused by the explosion of the 80 kg warhead — Overpressure in an enclosed space is determined using Weibull’s formula -

Overpressure Δp=2410(m/V) to the power 0.72

where: 2410 is a constant based on 1 bar (100 kPa; 15 psi)

M = Net explosive mass calculated using all explosive materials and their relative effectiveness

V = Volume of given area (primarily used to determine volume within an enclosed space).

We have two zones to measure the overpressure, the first inside the 3.5 m silo created by the SPICE 2000 penetrator. This gives us a value of approx. 12631 kPA for the overpressure wave within the dug up silo. This overpressure wave would have resonated through the rocky side, ejecting upward at a high velocity towards the two floors of the hall. Post expansion in the hall, the shrapnel and the overpressure wave would have killed all soft tissue targets on both the floors and penetrated the walls and roofs with deadly effect.

But was that enough to collapse the building? As per experimental data, a minimal overpressure of around 14 kPA is required to cause the collapse of a non-concrete structure. Since the volume of the building was very large with two floors inside the building, the overpressure blast wave from the 80 TNT kg warhead, had it exploded at the base of the building (not accounting for the penetration to 3.5 meters), would be in the tune of 19.28 kPA. This overpressure would have probablybrought down the building to implode and collapse. However, the explosion of the warhead 3.5 meters below the surface, with the rocky sides, walls bearing partial explosion and blast overpressure effects; will significantly dropped the overpressure value inside the compartmentalised hall. What would also be noteworthy is that the foundation and support beams would have been dug in the solid basalt rock, hence will require a significantly greater charge at core locations, than the low mass 80 kg TNT as part of this version of the SPICE 2000.

Though not basing assumptions on an empirical relationship and keeping well within the error margin, it can safely be assumed that the value of the blast overpressure wave would have fallen below 14 kPA, which — while causing extensive kinetic energy based shrapnel and overpressure pressure damage to the roof and the sides, would not have been sufficient to break open or collapse the side wall with intermixed concrete, and the main roof of the building. Also the fact that all the bombs wouldn’t have struck the target at the same time, compartmentalised damage would have occurred in the individual bomb’s sphere of influence.

Yes, there would have been significant casualties within this hall. The analysis for same is out of the purview for us.
I commend the author for the analysis involving the actual mathematics, specially overpressure. But it seems that it has been written with the intent to justify IAF's claim, by hook or by crook. Misleading assumptions have been made, and clever 'rounding off' has been done to prove the point.

Besides there are still some questions remaining to be addressed here. IAF claims that only 20% of the weapons missed their targets. Considering that 4x of them hit 100-200m off target, where did the rest of the 16x weapons hit?

I will conclude by stating the only possible explanation that would have made more sense. Most probably, the IAF struck the target 100-200m away with 4x SPICE-2000 SOWs (with general purpose munitions), INTENTIONALLY, to send a message to Pakistan. GoI (BJP) probably had already decided (in consent with the IAF & IA) to politicize the strike, regardless of any real damage. As it can be seen so far, the strike achieved its results at home for the GoI. Until the elections are over, explanations and theories will keep coming on Indian TV channels to justify the validity of GoI's claims. As long as the strike remains controversial, it will work out in GoI's favor.
 

Keysersoze

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Oct 13, 2006
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So you are saying that all those calculation is wrong?
That guy is a professional
Calculations only work if they have reliable numbers/data. If it is utter garbage then the calculation is garbage. GIGO

Cross posting:




Here's where the whole hole theory (no pun intended) began: Twitter user @rajfortseven, the retd. Col. Vinayak Bhatt of the IA. He posts his personal IMINT analysis, which has not been always correct (if anybody is interested, I can refer them to some tweets and why he was wrong there). The resolution of the PlanetLabs imagery is about 72 cm, and as the author rightly points out, we see SMUDGES. If anbody would care to look at the historical Google Earth imagery of the structure, they would realize that similar smudges have been on the roof of the structure in the past as well, in different locations. The most likely explanation for the smudges is the different nature of the CGI sheets used on the roof, probably due to repairs over the years. They might as well be tree branches broken off by high winds.

We now have 50 cm resolution satellite imagery from European Space Imaging, showing no signs of damage, captured on February 27th, 5 days before the date of the PlanetLabs imagery which was captured on March 4th. This imagery shows no visible holes or damage to the structure's roof. In all probability, Col. Bhat erred in his analysis and the low resolution combined with dark smudges gave him this idea. It is important to realize that the holes theory is the foundation of the entire argument.
https://www.euspaceimaging.com/paki...ms-india-missed-target-in-pakistan-airstrike/

Besides, Col. Bhatt concluded that SPICE-250s, not SPICE-2000s, were used in the strike. So which version is true?



There are two problems with the penetrator theory:

1. There is no indication of presence of any penetrator like that in IAF's service.

2. The said target did not require the use of a penetrator warhead. A "floor counting" fuse attached to a general purpose bomb would've achieved the required results. It is very hard to believe that a civilian structure at Balakot was in fact a bunker (built probably in the late 90s), the kind only found in military bases for the high command, considering that the location is neither an active war zone nor a military base.


There is no credible, irrefutable evidence of any kind of human loss in the attack. So, far, all claims have been conjecture (questionable audio and video clips, report of one odd journalist). There is no need to elaborate more on that.


Precisely! And to add to that, the hole theory proposes 4x holes and hence 4x SPICE-2000 SOWs, i.e. 280-320 kg of combined total TNT inside the hypothetical bombs. This is NOT an insignificant amount.


It is true that penetrator munitions work on this principle of combining estimated delay figures with smart features like microphones to detect number of penetrated floors. However, a SPICE-2000 kit (or any PGM kit) is DECOUPLED with the 2000lbs munition, as far as fuzing is concerned. The fuze of a penetrator munition is built into the casing, so that it can also survive the penetration shocks alongwith the explosive. This rules out the possibility that SPICE-2000 itself packs the sensors and fuzing mechanism for detonation.


What is also interesting to note is that many other structures also survived the 2005 earthquake. Were they all hardened bunkers as well, built for JeM's leadership?


This is a VERY MISLEADING comparison, specially because the entire henceforth article is based on the premise that the hypothetical 'penetrator bomb' (a 2000lbs munition used with the SPICE-2000 kit) had the characteristics of BLU-116. The BLU-116 Advanced Unitary Penetrator has 109 kg of explosive filling, SIGNIFICANTLY higher than the figure used in the later calculations (80 kg).

Regardless, is the author implying that US or Israel sold such a penetrator munition to IAF? When did this happen?
If not, did DRDO develop such a munition for IAF? When did this happen?


I commend the author for the analysis involving the actual mathematics, specially overpressure. But it seems that it has been written with the intent to justify IAF's claim, by hook or by crook. Misleading assumptions have been made, and clever 'rounding off' has been done to prove the point.

Besides there are still some questions remaining to be addressed here. IAF claims that only 20% of the weapons missed their targets. Considering that 4x of them hit 100-200m off target, where did the rest of the 16x weapons hit?

I will conclude by stating the only possible explanation that would have made more sense. Most probably, the IAF struck the target 100-200m away with 4x SPICE-2000 SOWs (with general purpose munitions), INTENTIONALLY, to send a message to Pakistan. GoI (BJP) probably had already decided (in consent with the IAF & IA) to politicize the strike, regardless of any real damage. As it can be seen so far, the strike achieved its results at home for the GoI. Until the elections are over, explanations and theories will keep coming on Indian TV channels to justify the validity of GoI's claims. As long as the strike remains controversial, it will work out in GoI's favor.
Another point is why would they use such a specialised.munition when a simple bomb could do the job just as well? What would they gain/lose? Frankly the argument is ludicrous.
 

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Cross posting:




Here's where the whole hole theory (no pun intended) began: Twitter user @rajfortseven, the retd. Col. Vinayak Bhatt of the IA. He posts his personal IMINT analysis, which has not been always correct (if anybody is interested, I can refer them to some tweets and why he was wrong there). The resolution of the PlanetLabs imagery is about 72 cm, and as the author rightly points out, we see SMUDGES. If anbody would care to look at the historical Google Earth imagery of the structure, they would realize that similar smudges have been on the roof of the structure in the past as well, in different locations. The most likely explanation for the smudges is the different nature of the CGI sheets used on the roof, probably due to repairs over the years. They might as well be tree branches broken off by high winds.

We now have 50 cm resolution satellite imagery from European Space Imaging, showing no signs of damage, captured on February 27th, 5 days before the date of the PlanetLabs imagery which was captured on March 4th. This imagery shows no visible holes or damage to the structure's roof. In all probability, Col. Bhat erred in his analysis and the low resolution combined with dark smudges gave him this idea. It is important to realize that the holes theory is the foundation of the entire argument.
https://www.euspaceimaging.com/paki...ms-india-missed-target-in-pakistan-airstrike/

Besides, Col. Bhatt concluded that SPICE-250s, not SPICE-2000s, were used in the strike. So which version is true?



There are two problems with the penetrator theory:

1. There is no indication of presence of any penetrator like that in IAF's service.

2. The said target did not require the use of a penetrator warhead. A "floor counting" fuse attached to a general purpose bomb would've achieved the required results. It is very hard to believe that a civilian structure at Balakot was in fact a bunker (built probably in the late 90s), the kind only found in military bases for the high command, considering that the location is neither an active war zone nor a military base.


There is no credible, irrefutable evidence of any kind of human loss in the attack. So, far, all claims have been conjecture (questionable audio and video clips, report of one odd journalist). There is no need to elaborate more on that.


Precisely! And to add to that, the hole theory proposes 4x holes and hence 4x SPICE-2000 SOWs, i.e. 280-320 kg of combined total TNT inside the hypothetical bombs. This is NOT an insignificant amount.


It is true that penetrator munitions work on this principle of combining estimated delay figures with smart features like microphones to detect number of penetrated floors. However, a SPICE-2000 kit (or any PGM kit) is DECOUPLED with the 2000lbs munition, as far as fuzing is concerned. The fuze of a penetrator munition is built into the casing, so that it can also survive the penetration shocks alongwith the explosive. This rules out the possibility that SPICE-2000 itself packs the sensors and fuzing mechanism for detonation.


What is also interesting to note is that many other structures also survived the 2005 earthquake. Were they all hardened bunkers as well, built for JeM's leadership?


This is a VERY MISLEADING comparison, specially because the entire henceforth article is based on the premise that the hypothetical 'penetrator bomb' (a 2000lbs munition used with the SPICE-2000 kit) had the characteristics of BLU-116. The BLU-116 Advanced Unitary Penetrator has 109 kg of explosive filling, SIGNIFICANTLY higher than the figure used in the later calculations (80 kg).

Regardless, is the author implying that US or Israel sold such a penetrator munition to IAF? When did this happen?
If not, did DRDO develop such a munition for IAF? When did this happen?


I commend the author for the analysis involving the actual mathematics, specially overpressure. But it seems that it has been written with the intent to justify IAF's claim, by hook or by crook. Misleading assumptions have been made, and clever 'rounding off' has been done to prove the point.

Besides there are still some questions remaining to be addressed here. IAF claims that only 20% of the weapons missed their targets. Considering that 4x of them hit 100-200m off target, where did the rest of the 16x weapons hit?

I will conclude by stating the only possible explanation that would have made more sense. Most probably, the IAF struck the target 100-200m away with 4x SPICE-2000 SOWs (with general purpose munitions), INTENTIONALLY, to send a message to Pakistan. GoI (BJP) probably had already decided (in consent with the IAF & IA) to politicize the strike, regardless of any real damage. As it can be seen so far, the strike achieved its results at home for the GoI. Until the elections are over, explanations and theories will keep coming on Indian TV channels to justify the validity of GoI's claims. As long as the strike remains controversial, it will work out in GoI's favor.
IAF wont announce all weapons purchasing details .
Only thing available in public domain is big ticket items .Small development they wont publish.And Indian institutions have a reputation in developing best by combining bests that available to them.
So DRDO might developed a penetrator and added spice kit in to that weapon.

Again penetrator will only use for high precise attack for high value target.

GoI must have to avoid any kind of civilian or military casualities .Because if anything like that happens ,we cant justify that to outside world.
Rest of those trees and wind are just assumption only .No proof.

A simple problem still remains,PA still not allowing international medias in that building complex.
If the attack was just outside somewhere .
They only had to relocate all those inhabitants to some other place .And just allow them to take picture of the building .
Why that is still not happening .?

6 weapons they deployed .One was not clear to launch .5 weapons they launched .4 hit the area precisely .One may be missed .
Everyones attention was towards Balakot but two other targets where in Muzzfarabad and Chakoti .


Calculations only work if they have reliable numbers/data. If it is utter garbage then the calculation is garbage. GIGO


Another point is why would they use such a specialised.munition when a simple bomb could do the job just as well? What would they gain/lose? Frankly the argument is ludicrous.
Entire ops purpose was non military pre emptive strike .
So zero tolerance towards civilian and military casualities.
 

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IAF wont announce all weapons purchasing details .
Only thing available in public domain is big ticket items .Small development they wont publish.And Indian institutions have a reputation in developing best by combining bests that available to them.
So DRDO might developed a penetrator and added spice kit in to that weapon.

Again penetrator will only use for high precise attack for high value target.

GoI must have to avoid any kind of civilian or military casualities .Because if anything like that happens ,we cant justify that to outside world.
Rest of those trees and wind are just assumption only .No proof.

A simple problem still remains,PA still not allowing international medias in that building complex.
If the attack was just outside somewhere .
They only had to relocate all those inhabitants to some other place .And just allow them to take picture of the building .
Why that is still not happening .?

6 weapons they deployed .One was not clear to launch .5 weapons they launched .4 hit the area precisely .One may be missed .
Everyones attention was towards Balakot but two other targets where in Muzzfarabad and Chakoti .




Entire ops purpose was non military pre emptive strike .
So zero tolerance towards civilian and military casualities.
It's BS and the indians know it is.
 

_Sherdils_

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Opinion
Balakot air strike: Why IAF used 907-kg ‘penetrator’ bombs to target Jaish terror camp
The Israeli SPICE 2000 used by IAF has an advanced electrical fuze, which accurately predicts the impact sequence and delay required to activate.
SAMEER JOSHI
13 March, 2019 5:33 pm

Illustration by ThePrint Team

At around 3.30 am on 26 February, Mirage 2000s of the Indian Air Force made shallow incursions inside Pakistan and targeted Jaish-e-Mohammed camps at Balakot, along with Muzaffarabad and Chakothi (in Pakistan Occupied Kashmir). The strike on the Markaz Syed Ahmad Shaheed madrasa complex located on Jaba hill-top in Balakot was the most significant amongst them, especially considering that the Indian Air Force had struck a target inside Pakistan for the first time since the 1971 war. The strikes were a direct response to the attack by the Pakistan-based terror proxy – JeM – on a CRPF convoy at Pulwama on 14 February in which over 40 Indian jawans had lost their lives.

The IAF used the Israeli made SPICE 2000 stand-off glide bomb to target Balakot. The SPICE 2000 is a glide bomb kit, fitted on a 2000 lb (907 kg) bomb. The IAF uses both the SPICE 1000 and 2000 kits. As per Indian Air Force sources, 5 x SPICE 2000s were utilised to target Balakot, while one bomb was brought back. These bombs fell within 2 metres of their designated mean points of impact (DMPI) in the targeted area. The Indian Air Force has publicly stated that it has synthetic image radar (SAR) imagery of the post-strike battle damage analysis, which confirms its claim that all targets were accurately hit.

Location of JeM’s Balakot terror training camp on Google Maps | Sameer Joshi
Meanwhile, Pakistan has denied any damage or casualties at Balakot, and said that the Indian payloads landed in the nearby forest, missing the targets completely. International satellite experts based on their reading of data available with private satellite networks post-strike, have ridiculed Indian claims that the bombs fell anywhere on the target. This has been widely supported by a large section of the western media, who have been sceptical about the accuracy of the attack. Pakistan, on its part, has completely sealed the targeted camp in Balakot, discouraging any independent verification of the damage.

What has baffled the world is why the 2000 lb bombs, which hit the madrassa complex, did not cause widespread explosive damage over the target. George William Herbert, an international weapon’s expert, tweeted a few days ago that a 2000 lb/907 kg bomb like the Mk 84 made of 428 kg trinitol high explosive core and a 479 kg of metal casing, would have obliterated the building, destroying it completely due to the shock wave travelling at over 1.83–2.13 km/s. Typically, it would double the pressure inside a standard three-storey building around 25 meters wide, further contributing to the damage.

Also read: Pakistan’s entire navy has been out at sea after India bombed Balakot

Latest OSINT data reveals that while at least two of the targeted structures are still standing – with dark smudges or holes visible on the rooftop of the biggest target — they also suggest that SPICE bombs have indeed penetrated the building. While the imagery is synonymous with SPICE strikes seen in Syria, this does not match up to the damage assessment for an Mk 84 or an equivalent bomb carried as part of the SPICE 2000 glide kit as brought out by George Herbert. Also, suspected use of Fuel Air Explosive (FAE) through the SPICE 2000 mission, supported by dark smudges seen in the target area imagery, is also seen as a possibility by some experts. In addition, there is indication of a deep penetration SPICE bomb hit north of the big hall, where a seeming heap of soil is present, which suggests that either the building collapsed after being targetted or the Pak Army has razed it to the ground post strike to hide the damage.

Post Strike Analysis of the target | Col Vinayak Bhatt | ThePrint
Also read: First satellite images show likely damage to Jaish Balakot camp but no massive destruction

IAF sources have recently confirmed that the Mirages had used the ‘penetrator’ version of the SPICE 2000 glide bomb, which has a 907 kg hard metal reinforced casing with an embedded ‘low mass’ TNT warhead of 70–80 kg of net explosive quantity (NEQ). This version is designed to target reinforced concrete installations like C2 centres, penetrating deep before carrying out a low mass explosion to eliminate all with shrapnel and a blast over pressure wave, and not necessarily collapsing the targeted installation. The IAF is confident that this is what has happened at Balakot. This theory is reinforced by the statement of Maulana Ammar, the younger brother of the JeM boss Masood Azhar, that the madrassa complex at Jabba top has indeed been hit by Indian bombs; as well as through discreet interviews with eyewitnesses in the area amid a media clampdown by the Pakistani army, which confirms witnessing at least 35 bodies of killed JeM militants and ISI operatives being taken out post-strike. Indian intelligence had estimated more than 250-300 individuals active inside the camp before the strike. Details of actual number of casualties remains sceptical as of now.

However, rather than being taken at a face value, this revelation has been further given an unwarranted spin within the media and intersecting theories. This is because even a 70–80 kg low mass TNT explosion would send shrapnel and corresponding shock waves upward of 1 km/s as dictated by the Gurney equation out to around 14 meters, enough to cause very significant damage to the targeted structure. Let’s hence diagnostically analyse the usefulness of the penetrator version of the SPICE 2000 as the bomb used by the IAF in its strike at Balakot.

The right deal for the job at hand?
The weapon to target matching suggests that the IAF was specifically looking to carry out a precision strikes and avoid large area collateral damage. As described after strike by the Indian Foreign Secretary, the ‘non-military preemptive strikes’ was aimed at targeting the JeM cadre while avoiding civilian and Pakistani military casualties. Hence the ‘penetrator’ version of the Spice 2000, with a low mass TNT warhead was the right fit for the mission as compared to the high mass Mk 84 bomb equivalent version, which would have inflicted significantly more area damage. The SPICE 2000 is an all-weather 1000 kg glide bomb kit, which uses 12 control surfaces to achieve a definitive range of 60 kilometres. It navigates with the help of IN/ GPS and approaching the target reduces the GPS errors using its electro optical/ infra-red terminal attack sensor. This matches what it sees with pre-loaded satellite/ drone imagery of the target through ‘scene matching’, rapidly reducing the margin of errors and impacting the target within a CEP of less than 3 meters.

Also read: BJP’s backroom warriors are realising they can’t bank on Balakot and are changing gears

The SPICE 2000 used by the IAF has an advanced electrical fuze, which accurately predicts the impact sequence and delay required to activate. This is especially useful when penetrating multiple floors of a building, before exploding on the right level. A microphone embedded with a microcontroller in the smart fuze is used, with the microphone measuring the number of impacts and the microcontroller counting the floors, until the bomb breaks through the desired number of floors. Used extensively by the Israeli Air Force in Lebanon and Syria against tactical battlefield targets and in urban areas, the SPICE 2000 has a near perfect operational reliability record. These fuses would be critical in penetrating the various targeted buildings with at least 2 levels.

The focus of SPICE 2000 strike was the madrasa complex at the north edge of Jaba top, dominated by a huge 30 meters (length) x 30 meters (width) x 8 meters (max height) white/gray main Madrassa building, used mostly for imparting lessons by the instructors to their trainees. This would possibly be the target for a solitary Spice 2000 bomb. Connected to this main hall is a set of buildings. Another concrete structure with two storeys 12 meters (length) x 10 meters (width) x 8 meters (height) is located to the north of the big hall, which housed the under-training ab-initio cadre of the JeM. This building would have been targeted with a SPICE 2000 bomb. There was a twin storey mosque to the right of this building and a shed further to the north. To the south of the big hall, across the training ground was a robust ‘U’ shaped concrete structure with sloped roof, housing the instructors, senior trainees and a guest house in each component. One SPICE 2000 bomb each, would certainly have been earmarked for the Guest House, the Instructor’s quarter and the senior trainee accommodation. The last target was the house of Umar Ghouri, the local JeM boss, who lived across the dirt track. This would be a certain target for a single SPICE 2000 bomb. It is believed that one of the SPICE 2000s malfunctioned and could not be launched by the Mirage 2000s. Hence in all probability, one of the targets out of the GH, instructors and senior trainee buildings would not have been engaged.

Pre-strike vintage images of the buildings show thin metal roofs, with light concrete layer and two storeys. The walls would be a mix of concrete, local bricks and mortar, reinforced by rough iron pillars and concrete for support as is common in the construction characteristics found in Balakot region. While viewing historic satellite imagery of the place, it’s interesting to note the camp mostly survived the 2005 Balakot earthquake which caused widespread devastation in the area.

Possible targets for IAF in the JeM Camp | Sameer Joshi
Post-strike imagery analysis done from the images available, has revealed that all the bombs impacted the roofs of the various targets at near vertical position. This would have been tactically planned by the IAF to achieve maximum penetration, before the bombs exploded. This may also explain the reason behind the IAF’s shallow incursions in Pakistan Occupied Kashmir, aiming to fire the SPICE 2000 well within its launch envelope to achieve the optimal vertical trajectory over the target, rather than launch it at the fringe range of 60 kilometres from Indian territory.

To be or not to be…
Let’s analyse the science of what happened post impact on 26 February at Jabba top, Balakot. If we compare the Israeli made SPICE 2000’s penetrator casing volume and weight; it is closest to the USAF’s BLU 116 penetrator used on the GBU 24/27 series 2000 lb bunker busting munition. As per information, the BLU 116 can penetrate 3.4 meters of reinforced steel (or 15 meters of earth) using a nickel cobalt steel alloy core. The Spice 2000 penetrator bomb has similar capabilities. Assuming that the SPICE 2000 hit the target at a near nadir point, it would have easily sliced through the thin metal/ light concrete roof and at least one semi concrete floor to hit the base floor with a decent foundation in the ground, which is largely made up of Bafliaz volcanic rock in the Balakot region. For the sake of calculating the impact force on a bunker class target, we will assume the SPICE 2000 is able to penetrate at least 3 meters of 500 PSI reinforced concrete (a figure which is certainly less than the actual) and 10m of earth.

We reverse calculate the average impact force on a reinforced concrete target as follows –

Average impact force = mgh ÷ d
m — Weight of the penetrator (907 kg)
g — Acceleration due to gravity (9.81 m/s)
h — AGL height where the bomb transitioned from glide mode to vertical drop trajectory (a minimal 500 metres estimated for the Balakot attack)
d — Depth of penetration

Therefore, Average impact force of SPICE 2000 on reinforced concrete is 1474 kN and on earth is 442 kN. Incidentally, the more a bomb penetrates into the ground, the lesser will be its average impact force. The Bafliaz volcanic rock at Balakot is composed of at least three quarters of alkaline basalt, which has a density of 2.8 g/cm3. The approximate density value for 500 PSI reinforced concrete is 2.9 g/ cm3, which is close to basalt. Taking the margins in error and chemistry of basalt, it can safely be assumed that after penetrating the roof and another possible floor, the impact value would have increased from the 442 kN on the roof and the first level to (taking an approx. 15 percent jump within margin of error) to 508 kN. However, with the penetrator intact and no major loss in momentum, the same 15 % error margin can be applied to the 1474 kN standard 500 PSI reinforced concrete penetration figure, this time reducing the average impact force to 1253 kN, giving us a penetration distance of 3.5 meters in the Bafliaz rock geology at Jaba top.

The SPICE 2000 flight profile and penetration into the rocky surface explained | Sameer Joshi
The smart fuze of the SPICE 2000 would have been set to explode after penetrating two layers as per the intelligence available before the strike. After digging deep 3.5 meters below the big hall, it would have triggered the explosion of 80 kilograms of TNT, with the Gurney equation estimating shrapnel release at nearly 1 km/ sec for an explosive equivalent of the TNT. At the same time, the expansion of the intensely hot gases at extremely high pressures in the fireball would have caused a shock wave to form, moving upward out of the dug in silo at nearly the same velocity out to an effective range of 14 meters. The main characteristic of this wave is that the pressure rises very sharply at the moving front, and falls off toward the interior region of the explosion. The variation of the pressure with distance from the centre of the fireball, at a given instant, is ideal for (instantaneously rising) shock front, which will eliminate any soft target in the region and cause significant damage to the structure and depending on the distance, will cause the structure to collapse.

Now let’s calculate the overpressure caused by the explosion of the 80 kg warhead — Overpressure in an enclosed space is determined using Weibull’s formula –

Overpressure Δp=2410(m/V) to the power 0.72 where: 2410 is a constant based on 1 bar (100 kPa; 15 psi); M = Net explosive mass calculated using all explosive materials and their relative effectiveness; V = Volume of given area (primarily used to determine volume within an enclosed space).

We have two zones to measure the overpressure, the first inside the 3.5 m silo created by the SPICE 2000 penetrator. This gives us a value of approx. 12631 kPA for the overpressure wave within the dug-up silo. This overpressure wave would have resonated through the rocky side, ejecting upward at a high velocity towards the single/ twin floors of the targets. Post expansion, the shrapnel and the overpressure wave would have killed all soft tissue targets and penetrated the walls and roofs with deadly effect.

But was that enough to collapse the buildings? As per experimental data, a minimal overpressure of around 14 kPA is required to cause the collapse of a non-concrete structure. Since the volume of the building was very large with two floors inside the building, the overpressure blast wave from the 80 TNT kg warhead, had it exploded at the base of the building (not accounting for the penetration to 3.5 meters), would be in the tune of 19.28 kPA. This overpressure would probably have brought down the buildings to implode and collapse. However, the explosion of the warhead 3.5 meters below the surface, with the rocky sides, walls bearing partial explosion and blast overpressure effects; will significantly drop the overpressure value inside the compartmentalised hall. What would also be noteworthy is that the foundation and support beams would have been dug in the solid basalt rock, hence will require a significantly greater charge to knock down core load bearing members, than the low mass 80 kg TNT of the penetrator version.

Also read: What Pulwama-Balakot proves: A ‘third’ actor can still push India and Pakistan into a war

Though not basing assumptions on an empirical relationship and keeping well within the error margin, it can safely be assumed that the value of the blast overpressure wave would have fallen far below 14 kPA, which — while causing extensive kinetic energy based shrapnel and overpressure pressure damage to the roof and the sides, would not have been sufficient to break open or collapse the side walls with intermixed concrete, and the main roofs of the building. Compartmentalised damage would have occurred in the individual bomb’s sphere of influence.

Yes, there would be significant casualties within the confines of the targets due to shrapnel, intense heat and overpressure waves.

One piece of the puzzle is still not clear: why are multiple entry points visible on the roof of the big hall, when the building may have been targeted only by a single SPICE 2000 as per the data available on the number of bombs and the speculated targets? In all probability, these would be the result of inside to outside blast incursions.

One can, however, clearly see the result of the attack on the trainee accommodation north of the main hall (Refer Target 1), where the building has been destroyed with deep ingestion marks and a lot of loose soil unearthed, the classic tell-tale signs of a penetrator warhead entering the ground and making a mould of earth around it. This indicates that there was more sub soil present than basalt rock, underneath the structure as mentioned or a cover-up operation underway by the Pakistani Army post blast. Since the IAF points out that all the SPICE 2000 bombs hit within the CEP, impact points on the other targets would indicate clean penetration and deep explosions, which while killing all, would not be sufficient to get the complete buildings down as is seen at other locations.

Possible Target Post Strike Analysis by the author. Image courtesy Planet Earth Labs
Did the IAF SPICE 2000s strike at the target ?  Yes, they did. This assessment is based on the science of it all, which can be debated by explosive experts for its worth. The Indian Air Force has done its job; let’s not overreact to anything and everything of it. One day we will know what happened below that roof.

So, when the Indian Air Chief says ‘We hit the targets’, believe me, he means serious business!

The author is an former fighter pilot with extensive experience on the Mirage 2000 and MiG 21 aircraft of the IAF.

This article was first published on Medium.

Want to hear experts engage over the big issues of the day? We bring you Talk Point.

Tags: Balakot air strikesIndia-Pakistan relationsIndian Air ForceMirage 2000Pulwama attack
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View Comments




    • Khan :
      13 March, 2019 at 6:17 pm
      Oh my God.
      Well... I am really happy to read all bogus and propaganda articles in Indian media, all most all paid by BJP & their supporter. But that’s good sign, how Indian manipulating their own people. I am shocked to see how famous name of India journalism, all are part of this propaganda paid by ruling party.

      All these articles, of course help to get BJP more vote (that’s the main goal right now) but for international community, they want hard core proof & evidence, which don’t exists.

      Keep the propaganda and get more vote for BJP and get more advertisement & money ;-)
    • Jerry :
      14 March, 2019 at 6:56 pm
      It is amazing to read how advanced warfare has gone in terms of scientific innovation. Proves the point when the External Ministry Spokesperson mentions that it was targeted at Terrorist infrastructure.
      For a pakistani this might be a fiction out of an Issac Assimov novel and rightly so. In a country where science books are all about Thr Supreme Lord and perhaps science at best means suicide belt and phd in science means someone who wears it and blows himself, such a frustration is understandable Mr. Khan.
      The truth about all the previous wars including Kargil have been told by some of the sensible journalists and surprisingly Army generals, so give this also some time and truth will come out.
      In India, we bow before our armed forces because of RESPECT and not FEAR( unlike with our neighbours).
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Copyright © 2019 Printline Media Pvt. Ltd. All Rights ReservedView Non-AMP Version

You dropped bombs and in return were bombed by a country which is the size of Utar Pradesh.

Your pilot was caught and paraded in front of the world.

According to you your military installations were bombed too whcih is an act of war.

What did you do in return? Sit and cry and complain about cheating that PAF used F-16s against you.

And btw, flaunting that exploded piece of missile, you looked like a rape victim displaying a used condom as proof that you were indeed raped!

Any sane nation would go into introspection and dive deep into what went wrong etc but you guys have gone on another level of dhitai to prove you have leveled off with Pakistan, a country 7 times smaller than you.

Aur ye chalen hain China se muqabla karney.

You want war at least display some chivalry like Saladin would send his physicians to Richard the lionheart because he didn't want to fight a sick king.
 

Thorough Pro

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LOL, what good are advanced electronics and accurate predictions when the bomb itself misses the target by 200 meters?

Please continue reading and uploading more such stuff, hopefully this will help heal your wounds.


Opinion
The Israeli SPICE 2000 used by IAF has an advanced electrical fuze, which accurately predicts the impact sequence and delay required to activate.
 

hussain0216

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What did you do in return? Sit and cry and complain about cheating that PAF used F-16s against you.

And btw, flaunting that exploded piece of missile, you looked like a rape victim displaying a used condom as proof that you were indeed raped!
Ain't it the truth!!!!

A wannabe supa pawa crying and moaning infront of the world that a country 7 times smaller in population slapped it
 

GumNaam

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Jinn Baba

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What a load of sh1t!

***The author is an former fighter pilot with extensive experience on the Mirage 2000 and MiG 21 aircraft of the IAF. He has seen combat in the 1999 Indo Pak Kargil conflict. He writes on military subjects and his article on the Air War in Syria, won the best military aviation submission at the 2017 Paris Airshow.
Let's start with the obvious - the author is a former IAF Mirage 2000 pilot, yet within the entirety of the write up, he could not name the bomb that had been used, nor does he state whether in his years with the IAF if he ever came across such a munition.

Instead, in the original article he posts a pic of "A SPICE 2000 kit with a Mk 84 HE bomb" to make his point. For those that dont know, this is what a MK-84 does when it hits a target:


Then, let's look at the official brochure of the SPICE 2000 kit and this too makes no mention of the type of bomb to which the author refers. The bombs which it refers to are all high explosive and similar to the MK-84.

May be neither a former IAF pilot nor Rafael know about this top secret bomb that the Indians built just for the Balakot strike (it has no other real world application), so let's go over to his analysis and see if it makes sense.

As per Indian Air Force sources, 5 x SPICE 2000s were utilised to target Balakot, while one bomb was brought back.
Interesting.

George William Herbert, an international weapon’s expert tweeted a few days back that a 2000 lb/ 907 kg bomb like the Mk 84 made of 428 kg trinitol high explosive core and a 479 kg of metal casing, would have obliterated the building, destroying it completely due to the shock wave travelling at over 1.83–2.13 km/s. Typically it would double the pressure inside a standard three storey building around 25 meters wide, further contributing to the damage.
But this former chaiwala (IAF pilot) feels that the actual weapons expert is wrong, because...

Latest OSINT data reveals that while at least two of the targeted structures are still standing - with dark smudges or holes visible on the rooftop of the biggest target, suggesting that SPICE bombs have indeed penetrated the building.
Here's the pic on which he relies:



Firstly, if you cant show a before and after pic, you cant claim "at least two of the targeted structures are still standing". Without a before and after comparrison, you either say you dont know, or assume that all the buildings are all standing.

Secondly, to any sane person, these are nothing more than dark patches or material on the roof.

But to the author, they are holes! And evidence that bombs penetrated the building.

Yet, according to IAF sources to which the author refers, 5 bombs were dropped targeting every building in the compound. If the dark patches are actually holes and the strike was completely successful, why can we not see the same dark patches or "holes" in any of the other buildings within this compound?

Why also has the date of the satellite pic on which the author relies not been revealed?

But here is the best part, he ends his piece with an update which defeats his entire analysis:

14MARCH EDIT 0800H— CONFIRMATION FROM INDIAN AIR FORCE ON TARGETS HIT : The IAF has confirmed through sources that the main hall (the biggest target seen) WAS NOT targeted by the SPICE Bombs.
So those "holes" turned out to be nothing but smudges! And now he relies on imagery of new smudges/holes on the other buildings - that he forgets were not present in the original image he posted :omghaha:

Let's address the other BS he comes out with:

While the imagery is synonymous with SPICE strikes seen in Syria,
o_O

I have never seen imagery where a relatively small structure remains fully standing with nothing more than small holes on its roof when a 1 ton bomb lands on it. And unsurprisingly, the author provides no such imagery.

If this is a successful strike, then the likes of USA and Israel are clearly doing it wrong.

In addition, suspected use of Fuel Air Explosive (FAE) through the SPICE 2000 mission, supported by dark smudges seen in the target area imagery is also seen as a possibility by some experts.
The author specifically names the expert who completely discredits India's claim, but fails to name the experts that suggest FAEs were used.

Again, in case people dont know, here is what a 1 ton FAE does:


Clearly, use of FAEs was likely to have caused more than a few holes worth of damage. Yet this idiot who served in the IAF believes otherwise.

The author then adds:

In addition, there is indication of a deep penetration SPICE bomb hit north of the big hall, where a seeming heap of soil is present.
But why would a "deep penetration SPICE bomb" target an empty field? Did it miss? If it hit a building, where is the debris? Or was the building made out of mud? Again, this analysis fails to answer obvious questions.

IAF sources have recently confirmed that the Mirages had used the ‘penetrator’ version of the SPICE 2000 glide bomb, which has a 907 kg hard metal reinforced casing with an embedded ‘low mass’ TNT warhead of 70–80 kg of net explosive quantity (NEQ). This version is designed to target reinforced concrete installations like C2 centres, penetrating deep before carrying out a low mass explosion to eliminate all with shrapnel and a blast over pressure wave, and not necessarily collapsing the targeted installation.
Why would IAF use bombs specifically made to hit "reinforced concrete installations" or underground bunkers when targeting such basic buildings?

This idiot then then answers this question by stating this:

This theory is reinforced by the statement of Maulana Ammar, the younger brother of the JEM boss Masood Azhar, that the madrassa complex at Jabba top has indeed been hit by Indian bombs; as well as through discreet interviews with eyewitness in the area amid a media clampdown by the Pak army, who confirm witnessing at least 35 bodies of killed JEM militants and ISI operatives being taken out post-strike.
Firstly, nothing he says here reinforces the theory that deep penetration bombs were used.

He provides no reference or proof that the brother of JeM boss accepted that bombs had hit.

He provides no proof or reference for the "discreet interviews with eyewitness in the area" to which he refers.

There is clearly no evidence or substance here.

He then blabbers on:

The weapon to target matching suggests that the IAF was specifically looking to carry out a precision strikes and avoid large area collateral damage. As described after strike by the Indian Foreign Secretary, that the ‘Non-military pre-emptive strikes’ was aimed at targeting the JeM cadre while avoiding civilian and Pak military casualties. Hence the ‘penetrator’ version of the Spice 2000, with a low mass TNT warhead was the right fit for the mission as compared to the high mass Mk 84 bomb equivalent version, which would have inflicted significantly more area damage.
Again, this is absolute BS!

First, the IAF claims (according to the author) to have used 5 1 ton bombs and targeted all the structures within this compound.

Second, the satellite imagery posted by the author clearly shows no other buildings near this compound.

Third, the author himself hints that perhaps FAEs may have been used.

So, there was no collateral damage to avoid. Even if there was, the IAF could have just used the Spice 250 or Spice 1000 kits mated with significantly lower yield bombs. And if it cared to avoid collateral damage, it wouldn't have used FAEs as the author suggests may have even used.

Post-strike imagery analysis done from the images available, has revealed that all the bombs impacted the roofs of the various targets at near vertical position.
Yet that imagery is not posted :rolleyes1:

As for his "analysis" as to why the buildings were not completely destroyed:

Though not basing assumptions on an empirical relationship and keeping well within the error margin, it can safely be assumed that the value of the blast overpressure wave would have fallen far below 14 kPA, which — while causing extensive kinetic energy based shrapnel and overpressure pressure damage to the roof and the sides, would not have been sufficient to break open or collapse the side walls with intermixed concrete, and the main roofs of the building.Compartmentalised damage would have occurred in the individual bomb’s sphere of influence.
Here is what a 129kg GBU 39 penetrator with a 62 kg explosive does:



Now imagine what a 1 ton bomb with 87kg of explosives would do.

This piece, like every other desperate attempt by the Indians to try and save face, is a load of BS!
 

khanmubashir

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Opinion
Balakot air strike: Why IAF used 907-kg ‘penetrator’ bombs to target Jaish terror camp
The Israeli SPICE 2000 used by IAF has an advanced electrical fuze, which accurately predicts the impact sequence and delay required to activate.
SAMEER JOSHI
13 March, 2019 5:33 pm

Illustration by ThePrint Team

At around 3.30 am on 26 February, Mirage 2000s of the Indian Air Force made shallow incursions inside Pakistan and targeted Jaish-e-Mohammed camps at Balakot, along with Muzaffarabad and Chakothi (in Pakistan Occupied Kashmir). The strike on the Markaz Syed Ahmad Shaheed madrasa complex located on Jaba hill-top in Balakot was the most significant amongst them, especially considering that the Indian Air Force had struck a target inside Pakistan for the first time since the 1971 war. The strikes were a direct response to the attack by the Pakistan-based terror proxy – JeM – on a CRPF convoy at Pulwama on 14 February in which over 40 Indian jawans had lost their lives.

The IAF used the Israeli made SPICE 2000 stand-off glide bomb to target Balakot. The SPICE 2000 is a glide bomb kit, fitted on a 2000 lb (907 kg) bomb. The IAF uses both the SPICE 1000 and 2000 kits. As per Indian Air Force sources, 5 x SPICE 2000s were utilised to target Balakot, while one bomb was brought back. These bombs fell within 2 metres of their designated mean points of impact (DMPI) in the targeted area. The Indian Air Force has publicly stated that it has synthetic image radar (SAR) imagery of the post-strike battle damage analysis, which confirms its claim that all targets were accurately hit.

Location of JeM’s Balakot terror training camp on Google Maps | Sameer Joshi
Meanwhile, Pakistan has denied any damage or casualties at Balakot, and said that the Indian payloads landed in the nearby forest, missing the targets completely. International satellite experts based on their reading of data available with private satellite networks post-strike, have ridiculed Indian claims that the bombs fell anywhere on the target. This has been widely supported by a large section of the western media, who have been sceptical about the accuracy of the attack. Pakistan, on its part, has completely sealed the targeted camp in Balakot, discouraging any independent verification of the damage.

What has baffled the world is why the 2000 lb bombs, which hit the madrassa complex, did not cause widespread explosive damage over the target. George William Herbert, an international weapon’s expert, tweeted a few days ago that a 2000 lb/907 kg bomb like the Mk 84 made of 428 kg trinitol high explosive core and a 479 kg of metal casing, would have obliterated the building, destroying it completely due to the shock wave travelling at over 1.83–2.13 km/s. Typically, it would double the pressure inside a standard three-storey building around 25 meters wide, further contributing to the damage.

Also read: Pakistan’s entire navy has been out at sea after India bombed Balakot

Latest OSINT data reveals that while at least two of the targeted structures are still standing – with dark smudges or holes visible on the rooftop of the biggest target — they also suggest that SPICE bombs have indeed penetrated the building. While the imagery is synonymous with SPICE strikes seen in Syria, this does not match up to the damage assessment for an Mk 84 or an equivalent bomb carried as part of the SPICE 2000 glide kit as brought out by George Herbert. Also, suspected use of Fuel Air Explosive (FAE) through the SPICE 2000 mission, supported by dark smudges seen in the target area imagery, is also seen as a possibility by some experts. In addition, there is indication of a deep penetration SPICE bomb hit north of the big hall, where a seeming heap of soil is present, which suggests that either the building collapsed after being targetted or the Pak Army has razed it to the ground post strike to hide the damage.

Post Strike Analysis of the target | Col Vinayak Bhatt | ThePrint
Also read: First satellite images show likely damage to Jaish Balakot camp but no massive destruction

IAF sources have recently confirmed that the Mirages had used the ‘penetrator’ version of the SPICE 2000 glide bomb, which has a 907 kg hard metal reinforced casing with an embedded ‘low mass’ TNT warhead of 70–80 kg of net explosive quantity (NEQ). This version is designed to target reinforced concrete installations like C2 centres, penetrating deep before carrying out a low mass explosion to eliminate all with shrapnel and a blast over pressure wave, and not necessarily collapsing the targeted installation. The IAF is confident that this is what has happened at Balakot. This theory is reinforced by the statement of Maulana Ammar, the younger brother of the JeM boss Masood Azhar, that the madrassa complex at Jabba top has indeed been hit by Indian bombs; as well as through discreet interviews with eyewitnesses in the area amid a media clampdown by the Pakistani army, which confirms witnessing at least 35 bodies of killed JeM militants and ISI operatives being taken out post-strike. Indian intelligence had estimated more than 250-300 individuals active inside the camp before the strike. Details of actual number of casualties remains sceptical as of now.

However, rather than being taken at a face value, this revelation has been further given an unwarranted spin within the media and intersecting theories. This is because even a 70–80 kg low mass TNT explosion would send shrapnel and corresponding shock waves upward of 1 km/s as dictated by the Gurney equation out to around 14 meters, enough to cause very significant damage to the targeted structure. Let’s hence diagnostically analyse the usefulness of the penetrator version of the SPICE 2000 as the bomb used by the IAF in its strike at Balakot.

The right deal for the job at hand?
The weapon to target matching suggests that the IAF was specifically looking to carry out a precision strikes and avoid large area collateral damage. As described after strike by the Indian Foreign Secretary, the ‘non-military preemptive strikes’ was aimed at targeting the JeM cadre while avoiding civilian and Pakistani military casualties. Hence the ‘penetrator’ version of the Spice 2000, with a low mass TNT warhead was the right fit for the mission as compared to the high mass Mk 84 bomb equivalent version, which would have inflicted significantly more area damage. The SPICE 2000 is an all-weather 1000 kg glide bomb kit, which uses 12 control surfaces to achieve a definitive range of 60 kilometres. It navigates with the help of IN/ GPS and approaching the target reduces the GPS errors using its electro optical/ infra-red terminal attack sensor. This matches what it sees with pre-loaded satellite/ drone imagery of the target through ‘scene matching’, rapidly reducing the margin of errors and impacting the target within a CEP of less than 3 meters.

Also read: BJP’s backroom warriors are realising they can’t bank on Balakot and are changing gears

The SPICE 2000 used by the IAF has an advanced electrical fuze, which accurately predicts the impact sequence and delay required to activate. This is especially useful when penetrating multiple floors of a building, before exploding on the right level. A microphone embedded with a microcontroller in the smart fuze is used, with the microphone measuring the number of impacts and the microcontroller counting the floors, until the bomb breaks through the desired number of floors. Used extensively by the Israeli Air Force in Lebanon and Syria against tactical battlefield targets and in urban areas, the SPICE 2000 has a near perfect operational reliability record. These fuses would be critical in penetrating the various targeted buildings with at least 2 levels.

The focus of SPICE 2000 strike was the madrasa complex at the north edge of Jaba top, dominated by a huge 30 meters (length) x 30 meters (width) x 8 meters (max height) white/gray main Madrassa building, used mostly for imparting lessons by the instructors to their trainees. This would possibly be the target for a solitary Spice 2000 bomb. Connected to this main hall is a set of buildings. Another concrete structure with two storeys 12 meters (length) x 10 meters (width) x 8 meters (height) is located to the north of the big hall, which housed the under-training ab-initio cadre of the JeM. This building would have been targeted with a SPICE 2000 bomb. There was a twin storey mosque to the right of this building and a shed further to the north. To the south of the big hall, across the training ground was a robust ‘U’ shaped concrete structure with sloped roof, housing the instructors, senior trainees and a guest house in each component. One SPICE 2000 bomb each, would certainly have been earmarked for the Guest House, the Instructor’s quarter and the senior trainee accommodation. The last target was the house of Umar Ghouri, the local JeM boss, who lived across the dirt track. This would be a certain target for a single SPICE 2000 bomb. It is believed that one of the SPICE 2000s malfunctioned and could not be launched by the Mirage 2000s. Hence in all probability, one of the targets out of the GH, instructors and senior trainee buildings would not have been engaged.

Pre-strike vintage images of the buildings show thin metal roofs, with light concrete layer and two storeys. The walls would be a mix of concrete, local bricks and mortar, reinforced by rough iron pillars and concrete for support as is common in the construction characteristics found in Balakot region. While viewing historic satellite imagery of the place, it’s interesting to note the camp mostly survived the 2005 Balakot earthquake which caused widespread devastation in the area.

Possible targets for IAF in the JeM Camp | Sameer Joshi
Post-strike imagery analysis done from the images available, has revealed that all the bombs impacted the roofs of the various targets at near vertical position. This would have been tactically planned by the IAF to achieve maximum penetration, before the bombs exploded. This may also explain the reason behind the IAF’s shallow incursions in Pakistan Occupied Kashmir, aiming to fire the SPICE 2000 well within its launch envelope to achieve the optimal vertical trajectory over the target, rather than launch it at the fringe range of 60 kilometres from Indian territory.

To be or not to be…
Let’s analyse the science of what happened post impact on 26 February at Jabba top, Balakot. If we compare the Israeli made SPICE 2000’s penetrator casing volume and weight; it is closest to the USAF’s BLU 116 penetrator used on the GBU 24/27 series 2000 lb bunker busting munition. As per information, the BLU 116 can penetrate 3.4 meters of reinforced steel (or 15 meters of earth) using a nickel cobalt steel alloy core. The Spice 2000 penetrator bomb has similar capabilities. Assuming that the SPICE 2000 hit the target at a near nadir point, it would have easily sliced through the thin metal/ light concrete roof and at least one semi concrete floor to hit the base floor with a decent foundation in the ground, which is largely made up of Bafliaz volcanic rock in the Balakot region. For the sake of calculating the impact force on a bunker class target, we will assume the SPICE 2000 is able to penetrate at least 3 meters of 500 PSI reinforced concrete (a figure which is certainly less than the actual) and 10m of earth.

We reverse calculate the average impact force on a reinforced concrete target as follows –

Average impact force = mgh ÷ d
m — Weight of the penetrator (907 kg)
g — Acceleration due to gravity (9.81 m/s)
h — AGL height where the bomb transitioned from glide mode to vertical drop trajectory (a minimal 500 metres estimated for the Balakot attack)
d — Depth of penetration

Therefore, Average impact force of SPICE 2000 on reinforced concrete is 1474 kN and on earth is 442 kN. Incidentally, the more a bomb penetrates into the ground, the lesser will be its average impact force. The Bafliaz volcanic rock at Balakot is composed of at least three quarters of alkaline basalt, which has a density of 2.8 g/cm3. The approximate density value for 500 PSI reinforced concrete is 2.9 g/ cm3, which is close to basalt. Taking the margins in error and chemistry of basalt, it can safely be assumed that after penetrating the roof and another possible floor, the impact value would have increased from the 442 kN on the roof and the first level to (taking an approx. 15 percent jump within margin of error) to 508 kN. However, with the penetrator intact and no major loss in momentum, the same 15 % error margin can be applied to the 1474 kN standard 500 PSI reinforced concrete penetration figure, this time reducing the average impact force to 1253 kN, giving us a penetration distance of 3.5 meters in the Bafliaz rock geology at Jaba top.

The SPICE 2000 flight profile and penetration into the rocky surface explained | Sameer Joshi
The smart fuze of the SPICE 2000 would have been set to explode after penetrating two layers as per the intelligence available before the strike. After digging deep 3.5 meters below the big hall, it would have triggered the explosion of 80 kilograms of TNT, with the Gurney equation estimating shrapnel release at nearly 1 km/ sec for an explosive equivalent of the TNT. At the same time, the expansion of the intensely hot gases at extremely high pressures in the fireball would have caused a shock wave to form, moving upward out of the dug in silo at nearly the same velocity out to an effective range of 14 meters. The main characteristic of this wave is that the pressure rises very sharply at the moving front, and falls off toward the interior region of the explosion. The variation of the pressure with distance from the centre of the fireball, at a given instant, is ideal for (instantaneously rising) shock front, which will eliminate any soft target in the region and cause significant damage to the structure and depending on the distance, will cause the structure to collapse.

Now let’s calculate the overpressure caused by the explosion of the 80 kg warhead — Overpressure in an enclosed space is determined using Weibull’s formula –

Overpressure Δp=2410(m/V) to the power 0.72 where: 2410 is a constant based on 1 bar (100 kPa; 15 psi); M = Net explosive mass calculated using all explosive materials and their relative effectiveness; V = Volume of given area (primarily used to determine volume within an enclosed space).

We have two zones to measure the overpressure, the first inside the 3.5 m silo created by the SPICE 2000 penetrator. This gives us a value of approx. 12631 kPA for the overpressure wave within the dug-up silo. This overpressure wave would have resonated through the rocky side, ejecting upward at a high velocity towards the single/ twin floors of the targets. Post expansion, the shrapnel and the overpressure wave would have killed all soft tissue targets and penetrated the walls and roofs with deadly effect.

But was that enough to collapse the buildings? As per experimental data, a minimal overpressure of around 14 kPA is required to cause the collapse of a non-concrete structure. Since the volume of the building was very large with two floors inside the building, the overpressure blast wave from the 80 TNT kg warhead, had it exploded at the base of the building (not accounting for the penetration to 3.5 meters), would be in the tune of 19.28 kPA. This overpressure would probably have brought down the buildings to implode and collapse. However, the explosion of the warhead 3.5 meters below the surface, with the rocky sides, walls bearing partial explosion and blast overpressure effects; will significantly drop the overpressure value inside the compartmentalised hall. What would also be noteworthy is that the foundation and support beams would have been dug in the solid basalt rock, hence will require a significantly greater charge to knock down core load bearing members, than the low mass 80 kg TNT of the penetrator version.

Also read: What Pulwama-Balakot proves: A ‘third’ actor can still push India and Pakistan into a war

Though not basing assumptions on an empirical relationship and keeping well within the error margin, it can safely be assumed that the value of the blast overpressure wave would have fallen far below 14 kPA, which — while causing extensive kinetic energy based shrapnel and overpressure pressure damage to the roof and the sides, would not have been sufficient to break open or collapse the side walls with intermixed concrete, and the main roofs of the building. Compartmentalised damage would have occurred in the individual bomb’s sphere of influence.

Yes, there would be significant casualties within the confines of the targets due to shrapnel, intense heat and overpressure waves.

One piece of the puzzle is still not clear: why are multiple entry points visible on the roof of the big hall, when the building may have been targeted only by a single SPICE 2000 as per the data available on the number of bombs and the speculated targets? In all probability, these would be the result of inside to outside blast incursions.

One can, however, clearly see the result of the attack on the trainee accommodation north of the main hall (Refer Target 1), where the building has been destroyed with deep ingestion marks and a lot of loose soil unearthed, the classic tell-tale signs of a penetrator warhead entering the ground and making a mould of earth around it. This indicates that there was more sub soil present than basalt rock, underneath the structure as mentioned or a cover-up operation underway by the Pakistani Army post blast. Since the IAF points out that all the SPICE 2000 bombs hit within the CEP, impact points on the other targets would indicate clean penetration and deep explosions, which while killing all, would not be sufficient to get the complete buildings down as is seen at other locations.

Possible Target Post Strike Analysis by the author. Image courtesy Planet Earth Labs
Did the IAF SPICE 2000s strike at the target ?  Yes, they did. This assessment is based on the science of it all, which can be debated by explosive experts for its worth. The Indian Air Force has done its job; let’s not overreact to anything and everything of it. One day we will know what happened below that roof.

So, when the Indian Air Chief says ‘We hit the targets’, believe me, he means serious business!

The author is an former fighter pilot with extensive experience on the Mirage 2000 and MiG 21 aircraft of the IAF.

This article was first published on Medium.

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Tags: Balakot air strikesIndia-Pakistan relationsIndian Air ForceMirage 2000Pulwama attack
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View Comments




    • Khan :
      13 March, 2019 at 6:17 pm
      Oh my God.
      Well... I am really happy to read all bogus and propaganda articles in Indian media, all most all paid by BJP & their supporter. But that’s good sign, how Indian manipulating their own people. I am shocked to see how famous name of India journalism, all are part of this propaganda paid by ruling party.

      All these articles, of course help to get BJP more vote (that’s the main goal right now) but for international community, they want hard core proof & evidence, which don’t exists.

      Keep the propaganda and get more vote for BJP and get more advertisement & money ;-)
    • Jerry :
      14 March, 2019 at 6:56 pm
      It is amazing to read how advanced warfare has gone in terms of scientific innovation. Proves the point when the External Ministry Spokesperson mentions that it was targeted at Terrorist infrastructure.
      For a pakistani this might be a fiction out of an Issac Assimov novel and rightly so. In a country where science books are all about Thr Supreme Lord and perhaps science at best means suicide belt and phd in science means someone who wears it and blows himself, such a frustration is understandable Mr. Khan.
      The truth about all the previous wars including Kargil have been told by some of the sensible journalists and surprisingly Army generals, so give this also some time and truth will come out.
      In India, we bow before our armed forces because of RESPECT and not FEAR( unlike with our neighbours).
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Just one problem in this bs penetrator r for bunkers with reinforced concrete
This was just a simple building now it could stand let alone appear without any damage apparently
Did they say 4 penetrator hit the target ???
That some vedic bs ;)
 

GumNaam

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Just one problem in this bs penetrator r for bunkers with reinforced concrete
This was just a simple building now it could stand let alone appear without any damage apparently
Did they say 4 penetrator hit the target ???
That some vedic bs ;)
well "bs" IS their air chief's name after all... :wacko:
 
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