Fire needs three things: oxygen, heat, and fuel. Conventional explosives, like black powder, use a mixture of fuel and oxidizer. On the other hand, a thermobaric bomb uses fuel, a conventional explosive, and picks up an oxidizer as it goes. 

Many people have heard of MOAB. Not just the National park in Utah, but the Massive Ordnance Air Blast, better known as the Mother Of All Bombs. MOAB is the most well-known example of a thermobaric bomb.


What Is a Thermobaric Bomb?

A thermobaric bomb uses all the oxygen in an area for its own use. Because the explosion needs oxygen in order to work, a thermobaric reaction actively seeks out oxygen on which to feed. When conventional explosives detonate, a shaped charge acts upon a projectile of some sort. A shotgun shell is an example of this: the primer charge is ignited by the firing pin, which then ignites a contained black powder charge, which ejects pellets from the muzzle.

When a thermobaric bomb is detonated, a small conventional charge within a larger fuel vessel is ignited. The charge begins to ignite the fuel mixture, which produces pressure within the container. The container ruptures, allowing the heated fuel mixture to disperse. The dispersed mixture then burns as it comes in contact with oxygen, continually expanding until the fuel or oxygen is consumed.

The fuel mixture acts as a shock wave as it expands, creating terrific pressure waves. If a person is near the explosion they can either be killed by the heat or the pressure. In confined areas, the concussive waves bounce off walls and ceilings, creating overlapping pressure waves. The name thermobaric comes from the Greek “therme” (heat) and “baros” (pressure).


Mother of All Bombs

The MOAB, developed in 2003 by the Air Force Research Laboratory and Dynetics, a U.S.-based aeronautics company, was first used operationally in 2017. It is a 22,000lb bomb, 18,500lb of which is the explosives packed inside. Because the skin of the bomb is so light, the MOAB is not designed to penetrate, but to hit softer targets.