Sure, you’ve heard of the Mother of All Bombs (or more properly, the GBU-43 Massive Ordnance Air Burst) bomb.
Now, the Air Force has started taking delivery of the MOP, or Massive Ordnance Penetrator. Weighing in at about 30,000 pounds, the MOP is a GPS/Inertial guided weapon designed to hold the deepest bunker and tunnel complexes at risk.
It wasn’t all that long before Desert Storm the Air Force and the Navy realized the Mk84 2000 pound General Purpose bomb (and its guided variants such as the GBU-10/GBU-24) just weren’t capable of defeating a large number of reinforced concrete targets. Accordingly, they developed the BLU-109 warhead. While aerodynamically similar to the Mk84, the BLU-109 penetrator had a much harder, thicker bomb casing, and a relatively small amount of explosive filler. With a laser guided bomb kit strapped on, it became a deadly weapon against aircraft shelters, bunkers, and such.
But in the early days of Desert Storm, the services were a tad surprised to find that even BLU-109s were bouncing off some targets. Something bigger was needed. In an astounding feat of improvisational engineering, surplus 8” howitzer barrels were capped with a hardened steel nose, and had a modified version of the GBU-24 guidance kit installed. A couple were built for testing, and a couple more were built for use in Iraq. They were hand built, and flown directly to the theater. They were so new, the molten poured explosive filler kept the outside of the bomb casing warm to the touch. Known as the GBU-28, it was used in the closing days of Desert Storm.
Still, as good as the GBU-28 is, people now know they have to dig deeper. But there’s actually something of a finite limit on how deep you can dig in your facilities. And no matter how deep you dig, there has to be a way in, and that’s the weak point. Accordingly, the MOP has been ordered. Sadly, no good video of it has been released. We’ll keep an eye out for some.