On Friday, the GBU-43 Massive Ordnance Air Blast (MOAB), popularly called the Mother of All Bombs, became the largest non-nuclear bomb ever to be dropped on a battlefield after the United States military used it against an ISIS target in Afghanistan’s Nangarhar province. What is this weapon, and how does it work?
What is the MOAB?
Weighing roughly 10,000 kg, and measuring 10 metres in length and a metre in width, the MOAB is a very high yield conventional GPS-guided munition, which was designed in 2002 by the US Air Force Research Laboratory. It was developed by the Alabama-based aeronautics company Dynetics at a reported cost of $ 16 million each for the Iraq War, and was first tested in 2003. But it had never been used in action until Friday.
How is the MOAB different?
For two reasons. One, it packs in 8,000 kg of explosives — in comparison, the average weight of most deployed conventional bombs is roughly 250 kg. Two, it is a thermobaric weapon, which uses oxygen from the surrounding air to generate an intense, high-temperature blast wave that packs an incredible amount of energy into a small, localised area. In comparison, most conventional bombs consist of a mix of fuel and oxygen-generating substances. Thermobaric weapons consist of almost entirely 100% fuel, and rely on atmospheric oxygen.
Does it work like other bombs?
No. Unlike a bomb designed to actually penetrate a building or the ground, the MOAB has a “proximity fuse” on its nose that ignites the warhead when it reaches a certain altitude above the ground. The height could vary between 50 feet and 1,000 feet. As the fuse blows, it blasts fuel into the air, which then atomises. It is followed by a secondary explosion which lights the fuel that has been atomised.
The US had dropped older-style fuel-air bombs during the Vietnam War in order to flatten large areas of forest for helicopter landing zones. It has also dropped at least one “daisy cutter” — an MOAB precursor — on al-Qaeda at the Tora Bora cave complex in Afghanistan at the start of NATO’s Afghanistan campaign.
How is the MOAB delivered?
The sheer weight of the MOAB makes it impossible for it to be delivered using conventional bombers. The bomb must, therefore, be carried in a big transport plane, like the C-130 used by the US military on Friday. It is then sucked out of the back of the cabin hold on a pallet using a massive parachute, before being guided by the GPS through the satellite to its target.
Is MOAB the world’s largest conventional bomb?
No, the MOAB is still only the second largest conventional bomb in the US arsenal, after the Massive Ordnance Penetrator (MOP) which has nearly double the quantity of explosive. Unlike the MOAB, which detonates shortly before hitting the surface, making it capable of destroying buildings and networks just below the surface, such as tunnels and caves, the MOP is able to penetrate much deeper, and reportedly take out military bunkers. But the MOAB remains the biggest non-nuclear bomb to be used ever in combat.
Is MOAB primarily a military tool or psychological tool?
The way the US has chosen to deploy the bomb and publicise its use, it is clearly being used more as a psychological tool. Within hours of the bombing, the Pentagon had posted a press release describing the attack and its alleged effect on ISIS positions. But there are bound to be questions about the use of such a bomb in a counterinsurgency operation in areas with a civilian population — apparently one of the reasons the MOAB was never used in Iraq.
A day after the US MOAB strike, General Dawlat Waziri, a spokesman for the Afghan Defence Ministry, said initial information indicated that 36 militants had been killed and three large caves destroyed. However, Attaullah Khogyani, a spokesman for the provincial governor’s office, said 82 militants had been killed.