Massive Ordnance Air Blast, MOAB – A Perspective

(Published in CASS Journal, Vol4, No.3. Jul-Sep 2017. ISSN 2347-9191)

On 13th April 2017 at 7:32 p.m. local time[1], U.S. Forces Afghanistan conducted a strike using a GBU-43/B Massive Ordnance Air Blast bomb, MOAB dropped from an U.S. aircraft on an ISIS (Khorasan) tunnel complex in Achin district, Nangarhar province, Afghanistan. Some of the immediate reactions were: –

-Mr Ashraf Ghani, the president of Afghanistan, said that the strike was “designed to support the efforts of the Afghan National Security Forces (ANSF)” and “precautions were taken to avoid civilian casualties”[2],

-Mr Hamid Karzai, Afghanistan’s former president condemned the attacks in a series of tweets saying “This is not the war on terror but the inhuman and most brutal misuse of our country as testing ground for new and dangerous weapons”[3]

In January 2015, the ISIS had announced the establishment of its Khorasan branch, it was also the first time the ISIS had officially spread its wings outside the Arab world. In December 2015, analyst Harleen Gambhir of Institute for the Study of War, ISW had indicated that ISIS is likely to expand in Afghanistan- Pakistan region[4] as ISIS associate Wilayat Khorasan, controlling Nangarhar province, had commenced attacking Kabul and Jalalabad. It was estimated that ISIS influence is likely to increase further due to many factors such as, infighting among Taliban, vacuum due withdrawal of international forces and reduction in competition with al-Qaeda due to support of Khorasan.

Nangarhar Province is located in eastern Afghanistan, on the Afghanistan – Pakistan border. It is bordered by Kunar and Laghman provinces in the north, Pakistan in the east and south, and Kabul and Logar provinces in the west. It provides the easiest passage to Pakistan from Afghanistan. Topographical Features of Nangarhar include Spin Ghar and Safed Mountain Ranges along the southern border; belt of forests along southern mountain ranges and in Dara-I-Nur District in north; Khyber Pass in Mahmund Dara District in east; bare soil, and rocky outcrop throughout centre of the province. Achin, the target of the MOAB on 13 April 2017, is one of the districts in southern Nangarhar, bordering Pakistan.

The ISIS (K) were using a tunnel and cave complex in Tora Bora area which was apparently created by Central Intelligence Agency, CIA for the Mujahideen in 1980 in their fight against the Soviets. Tora Bora has steep heights, mountains, valleys and caves. The Tora Bora CIA complex constitutes of miles of tunnels, bunkers and camps built with the financial support of CIA 35 miles south west of Jalalabad[5]. It is understood that the complex was built by the Saudi Binladen group and the young Osama bin Laden had played a big role in its construction. The complex is said to have its own ventilation and hydroelectric power supply system.  Subsequently Osama bin Laden had hidden in the same tunnel complex before escaping to Pakistan during attack on Tora Bora. The MOAB was dropped on the same mountain ridge in the Achin district of Nangarhar.[6]

Conventional/Incendiary/Fuel Air Explosive/Thermobaric Bombs

It is required to differentiate between conventional, incendiary, Fuel Air Explosive and Thermobaric bombs because MOAB is compared with different types of Bombs like the Russian 15, 650-pound Aviation Thermobaric Bomb of Increased Power (ATBIP) also called the FOAB (father of all bombs), as well as the 30,000-pound GBU-57A/B Massive Ordnance Penetrator (MOP).

Conventional Bombs. A conventional bomb is a metal casing filled with high explosives (HE). Conventional bombs are generally classified according to the ratio of explosive to total weight. They are mainly of three types namely general purpose or GP, penetration and cluster bombs (The Convention on Cluster Munitions (CCM) is an international treaty that has prohibited the use, transfer, and stockpiling of cluster bombs, which scatters submunitions (“bomblets”) over an area). A GP bomb produces a combination of blast and fragmentation effects with weight of its explosive filling approximately equal to half of its total weight. In the fragmentation bomb the explosive filling is up to 20% of its total weight, with fragmentation cases making up the remaining weight. The damage is caused due to fragments travelling at high velocities. The penetration bombs have up to 25/30% of explosive filling and remaining is taken up by the body designed for penetration.  The kinetic energy of the bomb or the shaped charge or a combination of both achieve the penetration of the target.

Incendiary Explosives. Incendiaries cause damage by fire. They are used to burn supplies, equipment, and structures.

Fuel Air Explosives FAE. These disperse an aerosol cloud of fuel ignited by a detonator to affect an explosion. The wave front expands rapidly due to overpressure and flattens objects in the vicinity of the FAE cloud, and also causes heavy damage in the neighbouring area. A FAE bomb contains fuel and two independent explosive charges. After deployment, the first explosive charge is used to burst open the fuel container at a predetermined height and disperse the fuel. The fuel disperses and mixes with atmospheric oxygen and flows around the target area. The second charge is then made to detonate the cloud, which creates a massive blast wave. The blast wave results in extensive damage to the target especially in enclosed spaces.

Thermobaric weapons. Thermobaric weapons have been designed to overcome the short comings of conventional weapons when used against fortified structures/buildings. The blast wave generated by thermobaric weapons are not designed for penetration and it is effective in causing blast damage in a large radius. Fuels are chosen on the basis of the exothermicity of their oxidation, ranging from powdered metals, such as aluminium or magnesium, to organic materials, possibly with a self-contained partial oxidant. During detonation of a high explosive bomb, rapid formation of a blast wave, thermal radiation, break-up of the munition casing, and acceleration of the fragments takes place. In the case of conventional blast/fragmentation warheads, a large part of the energy is consumed by the breaking-up of the shell and acceleration of the fragments. Thermobaric weapons have thin casings and maximum energy is released in a couple of microseconds as a blast/shock wave. In the initial detonation only a small part of energy gets released, the products of detonation thereafter suck oxygen from the air and burn in what is termed as after-burning[7]. This increases the blast pressure wave as well as the fire envelope.

Guidance of Bombs

Air to surface bombs today have either laser guidance kits or Global Positioning System, GPS guidance kits. The laser guided bombs were found to be difficult to deploy in bad weather/visibility conditions or when the targets could not be safely illuminated by the designator, and this led to the preference for GPS guided munitions. Munitions with integrated Inertial Navigation System, INS coupled to a GPS receiver like the Joint Direct Attack Munition (JDAM) of Boeing are all weather deployable. The GPS/INS coupled with a tail control system provide the guidance. The Aircraft provides the initializing position and velocity, the target coordinates are also fed/updated by the aircraft through a data link. With GPS, the bomb gives a circular error probable (CEP) of five meters and without the GPS (signal lost/not available/jammed) for flight times up to 100 seconds the CEP is 30 meters. Thus, the GPS/INS kits have enabled the bombs to have the following advantages[8]:

  • Deployable in all weather conditions.
  • Fire and forget capability, the aircraft can proceed to its next task after launch.
  • Enhanced Launch Acceptance Region or LAR because these kits enable the weapon to adjust the flight trajectory at the time of launch to hit the target.
  • GPS provides an accurate common time code for all systems.
  • Flight trajectory can be programmed to hit the target at desired angle of impact.

As a further improvement Laser JDAM is now operational which has an add on laser kit in addition to the GPS/INS to take care of manoeuvring targets and midcourse alterations. A new wing kit (extended range- ER) can also be added to extend the range of the bomb up to 38 nm.

The MOAB – ‘Mother of All Bombs’

The GBU-43/B (MOAB) is a large, powerful and accurately delivered conventional bomb. It has KMU-593/B GPS-guidance with fins and inertial gyro for pitch and roll control. The KMU-593/B kits have been further upgraded with SAASM (Selective Availability/Anti-Spoofing Module) technology in the GPS receivers. In a further improvement, the KMU-xxx/C kits are additionally fitted with Anti-Jam technology. The MOAB is a satellite guided improved version of the 15000-pound BLU-82 Daisy Cutter bomb. It is 30 feet in length with a diameter of 40.5 inches. The warhead is a BLU 120-B aluminium casing weighing 3000 pounds with an explosive weight of 18,700 pounds. The warhead is designed for blast effect. It was designed to be delivered by a C-130 and originally used the explosive Tritonal, a mixture of 80% Tri nitro toluene, TNT and 20% aluminium powder. It was first tested in March 2003 at Eglin Air Force Base in Florida, when it produced a mushroom cloud that could be seen up to 20 miles away[9]. The current explosive filling is 18,700 pounds of H6. H6 is a type of HBX explosive composition, which is a cast able military explosive mixture composed of 44.0% RDX (Cyclotrimethylene trinitramine), 29.5% TNT and 21.0% powdered aluminium by weight. The MOAB delivers a massive explosive blast (over pressure), with lesser fragmentation effects due to a thin-walled aluminium casing. MOAB is a good choice against caves and earthen tunnels since the pressure waves on entering the complex can severely injure personnel and collapse the structures. The MOAB provides a capability to perform psychological operations, attack large area targets, or hold at-risk threats hidden within tunnels or caves. It is not designed for deep penetration and is an area impact weapon.

The MOAB is cradle launched from C-130 Hercules or MC-130 Talon II aircraft by means of a drogue extraction parachute. [10] Thereafter, the MOAB is guided for approximately 3 nautical miles through a GPS system (with inertial gyros for pitch and roll control), JDAM actuators, and is stabilized by series of fixed wings and grid fins.  The MOAB does not use a retarding parachute, thus permitting the aircraft to fly at higher altitudes, and making it safer for US pilots.

Future Trends in Design and Development of Conventional Bombs

It is understood that nanotechnology is spearheading the development of highly potent explosives, however, not much information is available through open sources, much of it has to be gleaned from research papers and patents (for e.g. Patents like US20150210605 – Structure of energetic materials, US6955732 – Advanced thermobaric explosive compositions and WO2013119191A1 – Composition for a fuel and air explosion).

Essentially, Nano energetic materials (nEMs) perform better than conventional materials because of much larger surface area, which increases speed of reaction and larger energy release in much shorter time. Addition of Super thermites[11] (nano-aluminium based) have shown instantaneous increase in explosive power of existing compositions[12]. Further, use of nano-sized materials in explosives has significantly increased safety and insensitivity by as much as over 30% without affecting reactivity. It is predicted that nEMs would provide the same explosive power at mass up to two orders of magnitude less than the current explosive systems[13].

While Nanosizing of high explosives leads to increasing their explosive power[14] and decreasing their sensitivity to external forces[15], it also decreases its thermal stability. The shelf life of such explosives could therefore stand reduced; however, some patents reveal that this issue has also been resolved technically (e.g. patent US20120227613 Thermal enhanced blast warhead). In India, the work on explosives and propellants is being undertaken at High Energy Materials Laboratory, HEMRL, a Defence Research and Development Organisation, DRDO laboratory, and it is understood that the research in nEMs is progressing satisfactorily.

It can be envisaged that nEMs would replace the conventional explosives in the next decade. This would provide existing conventional weapons with explosive powers higher in magnitude by a factor of two and enhance the safety to external stimulation by at least 30%. In simple terms, a missile warhead having an explosive content of 200 kg of TNT equivalent would have an explosive power of 20,000 kg of TNT equivalent when substituted with nEMs material of same weight of 200 kg! This advancement could displace Tactical nukes from the battlefield.

Nanotechnology is permeating in all fields of design & manufacturing of weapons and ammunition. It is bringing unprecedented precision in weapon systems, robustness in triggering mechanisms and opening new frontiers in propellant and pyrotechnic functioning. In addition to explosive and propellants, Nanomaterials have ushered in innovative improvements in many characteristics of ammunition such as guidance, penetration capacity, embedded sensors for monitoring condition, embedded antennae for guidance and so on.

Russian Answer to MOAB

An Aviation Thermobaric Bomb of Increased Power (ATBIP) was tested by Russia on 11 September 2007. It was said to be the most powerful conventional bomb in the world, with a 7-Ton explosive mixture resulting in a devastating effect equivalent to 44 tons of TNT[16]. It was nicknamed the Father of All Bombs (FOAB). It was hinted that the FOAB contained a liquid fuel, such as ethylene oxide, mixed with energetic nano-aluminium powder, which was dispersed by a high explosive booster. Some reports speculated that the liquid fuel was purified using nano-filters. What caught the imagination of defense experts was the fact that the Russian FOAB had less fuel than the MOAB, but was four times more powerful. It was also probably the first time that the nonprofessional learned of the lethal uses of nanotechnology.

India’s Biggest Conventional Bomb – SPICE

India has acquired the 2000 pound Israeli SPICE (Smart, Precise Impact, Cost-Effective) bomb. It is the biggest bomb in the inventory of the Indian Airforce. Israel’s Rafael Advanced Defence System’s first precision guidance kit for dumb bombs was called the SPICE. SPICE kits claim a CEP (Circular error probable) of three metres. SPICE’s Automatic Target Acquisition capability works by comparing a real-time image received from the dual Charge-Coupled Device (CCD) and infrared seeker to a reference image stored in the weapon’s computer. The SPICE can be carried on Mirage 2000 as well as on a variant of SU-30 MK1 aircraft of the Indian Air Force. The SPICE-2000 is stated to have a stand-off range of 32.3nm (60km).

MOAB the New WMD?

‘In the more distant future, weapons systems based on new principles (beam, geophysical, wave, genetic, psychophysical and other technology) will be developed. All this will, in addition to nuclear weapons, provide entirely new instruments for achieving political and strategic goals. Such hi-tech weapons systems will be comparable in effect to nuclear weapons but will be more “acceptable” in terms of political and military ideology. In this sense, the strategic balance of nuclear forces will play a gradually diminishing role in deterring aggression and chaos.[17]

Vladimir Putin, 2012

There are differing definitions of weapons of mass destruction WMD, therefore it is better to adhere to the one adopted by the United Nations. The definition of WMD was arrived at by the United Nations Convention on Conventional Armament in its first resolution in 1948.The Commission advised the Security Council that “all armaments and armed forces, except atomic weapons and weapons of mass destruction fall within its jurisdiction” and also stated that “weapons of mass destruction should be defined to include atomic explosive weapons, radioactive material weapons, lethal chemical and biological weapons, and any weapons developed in the future which have characteristics comparable in destructive effect to those of the atomic bomb or other weapons mentioned above”.[18] This definition provides the guidelines to distinguish between the conventional weapons and the WMDs.

The determining factors distinguishing the Conventional weapons from the WMD could be the terms Mass Causalities and Mass Destruction. However, mass casualties can also be inflicted by conventional weapons during extended periods of siege or carpet bombings. There is ambiguity in the sense that that event of occurrence of mass casualties could be a single event or a series of consecutive events. The number of casualties could in fact be higher in sustained usage of conventional weapons than in the case of a single use WMD. The other notable point is that there is no quantification of the term ‘Mass’, i.e. how many dead humans would qualify for an event to be termed as Mass casualty. The term mass destruction also suffers from similar dichotomy.  A barrage of conventional weapons can cause a larger scale physical destruction spread across tens of miles as compared to a single WMD in a single event, again, quantification as to what constitutes Mass Destruction has not been defined clearly.

The MOAB has been incorrectly compared to a nuclear bomb. It has less than 1000th[19] of the power of the atomic bomb ‘Little Boy’ dropped on Hiroshima because the MOAB blast was equivalent to 11 tons of TNT whereas the Hiroshima blast was close to 13000 tons equivalent of TNT.  The ‘Fat Man’ atomic bomb dropped on Nagasaki was a 20,000 tons equivalent of TNT. However, the blast radius of MOAB lies in the same one mile radius as the atomic bombs of WWII. Conventional bombs can never achieve the damage potential of the exponential rise of energy that ensues upon a nuclear bombs detonation. The most powerful of nuclear bombs today is the B83 bomb of the United States, it uses a fission process similar to that used in the atomic bombs, the initial energy is then used to ignite a fusion reaction in a secondary core of the hydrogen isotopes deuterium and tritium. The nuclei of the hydrogen atoms fuse together to form helium, and result in a chain reaction leading to a far more powerful explosion. The nuclear fission bomb B83, has a blast equivalent to 1,200,000 tons of TNT compared to 11 tons equivalent of TNT blast by the MOAB. The tactical nuclear weapons range from 10 tons to 100 kilotons. What unambiguously differentiates a conventional weapon from a WMD would be the latent effects of the deployment, which in case of atomic/nuclear weapons last across generations in case of humans and decades in case of remediation of the material. The UN definition of WMD covering atomic, radiological, chemical, biological, or any weapon producing similar effects appears to be sustainable, from this it can be inferred that MOAB/FOAB type of conventional bombs; which lie on the lowest limits of the destructive power of tactical nukes without the attendant latent effects; would not fall in the category of WMD.

An U.S. Air Force Special Operations Command MC-130 Combat Talon transport aircraft dropped the MOAB out of the cargo ramp on 13th April 2017.The bomb detonated at 7.32 pm local time in the Achin district of the eastern province of Nangarhar[20].  The Guardian reported that “a local security official said they had requested a large strike because fighter jets and drones had failed to destroy the tunnel complex”. Also, Ismail Shinwari, the district governor of Achin, said, “the strike was closely coordinated with Afghan soldiers and special forces, and tribal elders had been informed to evacuate civilians.[21] He also told AFP that that at least 92 ISIL fighters were killed in the bombing.[22] It was confirmed later by the Afghan officials that foreign militants, including 13 Indians, were also killed in the bombing.[23] The Indians had joined ISIS and were fighting for caliphate.

The MOAB had proved itself in Global War on Terror.


[1] U.S. Bombs, Destroys Khorasan Group Stronghold in Afghanistan. U.S. Department of Defense. 13 April 2017. (Accessed 25 May 2017)

[2] D’Angelo, Bob. “Afghan official: 36 ISIS fighters killed by ‘MOAB’”. 14 April 2017. (Accessed 28 May 2017)

[3] “U.S. drops ‘mother of all bombs’ in Afghanistan, marking weapon’s first use”. CBS News. 13 April 2017. (Accessed 03 Jun 2017)

[4] Harleen Gambhir, ISIS in Afghanistan: ISW Research. 3 December 2015. (Accessed 28 May 2017)

[5] Weaver, Mary Anne. “Lost at Tora Bora”. The New York Times. 11 September 2005. (Accessed 25 May 2017).

[6] Robertson, Nic (2017-14-04) MOAB hit caves used by ISIS, drug smugglers and Osama bin Laden. CNN. (Accessed 03 Jun 2017)

[7] Dr Anna E Wildegger-Gaissmaier. Aspects of thermobaric weaponry. ADF Health Vol 4 April 2003. (Accessed 25 May 2017)

[8] Attariwala, Joetey. Dumb Bombs with Graduate Degrees, Armada International. 27April 2017. (Accessed 28 May 2017)

[9] Mizokami, Kyle. U.S. Air Force Drops the Largest Conventional Bomb Ever Used in Combat. 13Apr 2017. (Accessed 03 Jun 2017)

[10] GBU-43/B “Mother of All Bombs”, (Accessed 05 Jun 2017)

[11] Nano-Thermite or Super-Thermite is a metastable intermolecular composite (MICs) containing an oxidizer and a reducing agent, which are intimately mixed on the nanometer scale. This dramatically increases the reactivity relative to micrometer -sized powder thermite. MICs, including nano-thermitic materials, are a type of reactive materials investigated for military use, as well as for general applications involving propellants, explosives, and pyrotechnics.

[12] Gartner, John. “Military Reloads with Nanotech.” Technology Review, an MIT Enterprise, 21 January 2005. (Accessed 25 May 2017)

[13] Yang, Guangcheng, Fude Nie, Jinshan Li, Qiuxia Guo, and Zhiqiang Qiao. “Preparation and Characterization of Nano-NTO Explosive.” Journal of Energetic Materials, 25, 2007.

[14] Kaili Zhang, Carole Rossi, and G.A. Ardila Rodriguez. “Development of a Nano-Al/CuO Based Energetic Material on Silicon Substrate.” Applied Physics Letters No. 91, 14 September 2007.

[15] Guangcheng Yang, Fude Nie, Jinshan Li, Qiuxia Guo, and Zhiqiang Qiao. “Preparation and Characterization of Nano-NTO Explosive.” Journal of Energetic Materials, 25, 2007.

[16] Russia tests giant fuel-air bomb. BBC. 12 Sep 2007. / (Accessed 28 May 2017)

[17] Vladimir Putin, “Being Strong: National Security Guarantees for Russia,” Rossiiskaya Gazeta, February 20, 2012, (Accessed 25 May 2017)

[18] Commission on Conventional Armaments (CCA), UN document S/C.3/32/Rev.1, August 1948, as quoted in UN, Office of Public Information, The United Nations and Disarmament, 1945–1965, UN Publication 67.I.8, 28.

[19] Tayag, Yasmin. How Does the “Mother of All Bombs” Compare to a Nuclear Bomb? 13 April 2017. (Accessed 03 Jun 2017)

[20] Ackerman, Spencer; Rasmussen, Sune Engel (14 April 2017). “36 Isis militants killed in US ‘mother of all bombs’ attack, Afghan ministry says”. The Guardian. (Accessed 28 May 2017)

[21] Rasmussen, Sune Engel. “‘It felt like the heavens were falling’: Afghans reel from MOAB impact”. The Guardian. 14 April 2017. (Accessed 25 May 2017).

[22] “IS death toll hits 90 from huge US bomb in Afghanistan”. Times Live. 15 April 2017. (Accessed 05 Jun 2017)

[23] “13 suspected Indian IS fighters killed as MOAB hit Afghanistan: Reports”. Hindustan Times. 18 April 2017. (Accessed 03 Jun 2017)