GBU-57
The *GBU-57 Massive Ordnance Penetrator (MOP) is a 30.000-pound (13.600 kg) precision-guided bunker-buster bomb developed by Boeing for the United States Air Force.
The weapon was first tested in 2007 and achieved Initial Operational Capability (IOC) in 2011. The GBU-57 experienced its first operational use on June 22, 2025, when seven B-2 Spirit bombers dropped 14 GBU-57 bombs on Iranian nuclear facilities during Operation Midnight Hammer.
The GBU-57 measures approximately 20.5 feet in length with a diameter of 31.5 inches and can vary by specific variant. The weapon weighs approximately 13.600 kg (30.000 pounds) with an explosive payload of 5.300-5.740 pounds (2.400-2.700 kg). The bomb consists of a BLU-127 series warhead and a KMU-612 tail kit containing GPS/INS guidance systems.
The weapon uses grid fins for flight control rather than conventional planar fins due to their superior performance at high Mach flight regimes and their ability to fold for storage in B-2 bomb bays. The bomb can reportedly penetrate at least 200 feet (60m) of ground or reinforced concrete before detonation.
Development of the MOP began in 2003 following analysis of bunker-buster effectiveness during Operation Iraqi Freedom, which revealed insufficient penetration capabilities of existing weapons. The Defense Threat Reduction Agency (DTRA) initiated the MOP program, with the Air Force Research Laboratory leading development and Boeing serving as the primary contractor.
In July 2004, the USAF requested proposals from defense contractors for a 30.000-pound precision-guided bomb capable of destroying deep underground targets. Boeing received a $30 million contract in November 2004 for the MOP project. Development proceeded through three phases: * Concept Refinement (completed May 2005)
- Detailed design and testing (June 2005 onwards)
- Weapon Performance Demonstration (November 2007-July 2008).
Flight testing using B-52 aircraft occurred between November 2007 and July 2008 at White Sands Missile Range. Northrop Grumman received contracts to modify B-2 bombers to carry the weapon. The first production order of eight MOPs was placed in April 2011 for $28 million.
There are multiple GBU-57 variants, each documented in their own page on the variants page, such as the GBU-57/B, GBU-57A/B, GBU-57C/B etc.
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