American forces dropped the GBU-43/B Massive Ordnance Air Blast (MOAB) bomb on an ISIS cave complex in Nangarhar Province, Afghanistan, early in the morning local time on April 13, 2017. GBU-43/B, also nicknamed the Mother Of All Bombs with the same acronym as above, was designed to intimidate, as part of the original “Shock and awe” campaign in the 2003 Iraq War. The weapon was never used in that conflict, but it was developed during the same period.
The MOAB device bears a charge of 18,700 lbs (8500 kg), composed mostly of H6, which is itself made of RDX. H6 is a standard-issue plastic explosive used by the American military for general-purpose bombs. RDX is a WWII-era plastic explosive, and one of the principal ingredients in Semtex. It’s very stable under normal handling, refusing to explode without a detonator — even unresponsive to small arms fire. While the MOAB was definitely designed to accomplish its goals with a mammoth pressure wave, it is neither a thermobaric weapon nor a fuel-air explosive (FAE). FAEs and thermobaric weapons are conceptually similar to each other as well as the MOAB, because they all use the combination of a shock wave and igniting the volume behind it, but they’re both different from a device like this.
The MOAB is considered the successor to the BLU-82 Daisy Cutter, which was developed during Vietnam for instantly clearing forests so helicopters could land. The last of the BLU-82’s were used by 2008, which is why the MOAB was developed to replace them. The MOAB is intended for use against “soft” targets. It is the largest conventional bomb we have, but it is not the largest penetrator — that’s the Massive Ordnance Projectile, or MOP. “Bunker busters” like the MOP can be compared with a shape charge, in that they are designed to spear through the roof and floors of hardened structures, destabilizing them, and then bury itself in the ground below the structure so that it can explode and destroy the target from beneath.
The MOAB accomplishes its destructive purpose in a different manner. It explodes above the surface, creating an expanding sphere of debris behind a concussive wave. It’s a little like how a tornado can take the roof off a building without hitting the building: Air is matter, and when that matter is shoving hard enough in through the windows and doors, it can blow the roof right off. Particulate aluminum in the MOAB’s charge functions much like any powdered metal does in civilian pyrotechnic displays, such as your bog standard road flares and July 4th fireworks.
MOAB is the most powerful non-nuclear bomb in the American arsenal, but not necessarily the most powerful in the world. The Russians have a FOAB, their “Father of All Bombs.” We think the FOAB is a thermobaric weapon, but its capabilities aren’t well known and it hasn’t been independently verified. The Russians claim it to be four times larger than the MOAB. Just for a sense of scale, both of these massive weapons pale in comparison to even small nuclear weapons. MOAB is a 22,600-pound bomb with a blast yield equivalent to 11 tons of TNT. The Russian device is supposedly 44 tons of TNT-equivalent. The first nuclear weapon we dropped weighed something like 9,700 pounds, but had a blast yield of 15 kilotons. And beyond all these, there’s the Tsar Bomba: the most powerful nuclear device ever tested by mankind. This is a weapon confined to the realm of rhetoric even by madmen.
Even so, the MOAB is so large, it can’t be dropped by a conventional bomber. It has to be shoved out the back of a C-130 military cargo plane. It’s also the largest satellite guided weapon (not the largest bomb, but the largest satellite-guided bomb).
Reports indicate that up to 36 ISIS terrorists were killed in the detonation Thursday.