Massive Ordnance Penetrator

GBU-57A/B Massive Ordnance Penetrator
GBU-57 MOP prototype
Type	"Bunker buster" bomb
Place of origin	United States
Service history
Used by	United States Air Force
Production history
Manufacturer	Boeing
Specifications
Weight	30,000 pounds (14,000 kg)
Length	20.5 feet (6.2 m)
Diameter	31.5 inches (0.80 m)

The GBU-57A/B Massive Ordnance Penetrator (MOP) is a U.S. Air Force, precision-guided, 30,000-pound (14,000 kg) "bunker buster" bomb. This is substantially larger than the deepest penetrating bunker busters previously available, the 5,000-pound (2,300 kg) GBU-28 and GBU-37.

In 2002, Northrop Grumman and Lockheed Martin were working on the development of a 30,000-lb (13,600 kg) earth-penetrating weapon, said to be known as "Big BLU". But funding and technical difficulties resulted in the development work being abandoned. Following the 2003 invasion of Iraq, analysis of sites that had been attacked with bunker-buster bombs revealed poor penetration and inadequate levels of destruction. This renewed interest in the development of a larger bunker-buster, and the MOP project was initiated by the Defense Threat Reduction Agency to fulfill a long-standing Air Force requirement.

The U.S. Air Force has not officially recognized specific military requirement for an ultra-large bomb, but it does have a concept for a collection of massively sized penetrator and blast weapons, the so-called "Big BLU" collection, which includes the MOAB (Massive Ordnance Air Burst) bomb. Development of the MOP was performed at the Air Force Research Laboratory, Munitions Directorate, Eglin Air Force Base, Florida with design and testing work performed by Boeing. It is intended that the bomb will be deployed on the B-2 bomber, and will be guided using GPS.