Massive Ordnance Penetrator (MOP) Statistics 2026 | Key Facts

What Is Massive Ordnance Penetrator (MOP) ?

The GBU-57 Massive Ordnance Penetrator (MOP) — formally designated the GBU-57A/B in its primary production standard, with the current generation GBU-57F/B as the most advanced fielded variant — is the largest, most powerful, most deeply penetrating conventional bomb ever built, a 30,000-pound (13,608 kg), 20.5-foot-long (6.2 m), 31.5-inch-diameter GPS-guided precision munition developed by Boeing for the United States Air Force (USAF) under a program originally initiated by the Defense Threat Reduction Agency (DTRA) in 2004, designed for one singular, uncompromising purpose: to reach and destroy hardened, deeply buried targets (HDBTs) — underground nuclear enrichment facilities, buried weapons of mass destruction production sites, and hardened command-and-control bunkers — that every other conventional weapon in the U.S. arsenal cannot touch. The MOP is not a bomb in the conventional sense of the word. It is a kinetic energy penetrator of extraordinary mass — dropped from altitude by a Northrop Grumman B-2 Spirit stealth bomber, gathering speed as it falls, striking the ground at over 1,000 feet per second, driving through reinforced concrete and limestone rock with the momentum of a 15-ton steel projectile, and detonating its 5,300-pound (2,400 kg) explosive payload of AFX-757 and PBXN-114 deep inside the buried structure — creating a lethal combination of blast, fragmentation, and overpressure that travels through tunnels and chambers destroying hardware, equipment, and personnel that no surface explosion could reach. The USAF officially states that the GBU-57 can penetrate up to 200 feet (61 m) of unspecified material before detonating — with independent analysts at Janes Information Services confirming approximately 200 feet (61 m) of earth or 60 feet (18 m) of reinforced concrete — making it the only weapon in any nation’s inventory capable of threatening Iran’s deeply buried Fordow Uranium Enrichment Plant, carved into the side of a mountain at approximately 300 feet underground.

The bomb carries 7 variants — from the original GBU-57/B through the current GBU-57F/B — each incorporating progressively improved fuzing, guidance, and warhead technology, and it is equipped with the Large Penetrator Smart Fuze (LPSF), which adjusts detonation timing based on the depth and structural characteristics of the target encountered during penetration, including void-sensing capability that triggers detonation upon entering large underground chambers even if the weapon has not reached its programmed depth. Due to its extraordinary size and weight, the GBU-57 MOP can only be deployed operationally from the B-2 Spirit stealth bomber, which carries two bombs — one in each internal weapons bay — the only aircraft in the U.S. inventory with payload bays large enough to accommodate the 20.5-foot weapon while maintaining the stealth profile necessary to penetrate defended airspace over a target hardened enough to justify the MOP’s use.

On June 22, 2025, the GBU-57 Massive Ordnance Penetrator made the transition from the most consequential weapon in the U.S. arsenal that had never been used in combat to the most consequential weapon in the U.S. arsenal that had just changed the strategic landscape of the Middle East. Seven B-2 Spirit stealth bombers — departing from Whiteman Air Force Base, Missouri, flying a 36-hour, 13,000-mile round trip in the longest B-2 mission since the opening of the Afghanistan war in 2001, supported by dozens of aerial refueling tankers, more than 125 total aircraft, and hundreds of maintenance and operational personnel — dropped 14 GBU-57 MOP bombs on Iran’s Fordow Uranium Enrichment Plant and Natanz Nuclear Facility in the early hours of June 22, 2025. Gen. Dan Caine, Chairman of the Joint Chiefs of Staff, confirmed at a Pentagon press briefing that the lead B-2 dropped its first two MOPs on Fordow at approximately 6:40 p.m. Eastern / 2:10 a.m. Iran time, with all seven bombers completing their target runs for a total of 14 MOPs dropped against two nuclear target areas.

Defense Secretary Pete Hegseth described the strike as the first operational employment of the MOP — confirming it was the longest B-2 Spirit mission since 2001 and that the weapon carries explosive power more than 10 times that of its predecessor. Gen. Caine confirmed that all 14 bombs guided to their intended aim points, functioned as designed, and detonated — and that the primary kill mechanism was a combination of overpressure and blast energy driving through the open tunnel network and destroying critical hardware throughout the facility interior. A trailing B-2 pilot who observed the first weapon detonations described the explosions as the brightest he had ever witnessed, appearing as full daylight despite occurring in complete darkness at 2:10 a.m. local time. Satellite imagery from Maxar Technologies taken immediately after the strikes showed multiple large-diameter holes or craters on the ridge above the Fordow complex, tunnel entrances blocked by debris, and a layer of grey-blue ash across a large swath of the surrounding area. Initial battle damage assessments confirmed all three target sites sustained extremely severe damage and destruction — and as of March 2026, the USAF is actively replenishing its MOP stocks with a Boeing $100 million+ sole-source contract, acknowledging the weapon’s combat expenditure in the most direct possible terms. The MOP had been designed, built, tested, and stored for 20+ years for exactly one scenario. On June 22, 2025, that scenario arrived — and the weapon worked.

Massive Ordnance Penetrator (MOP) 2026 — Key Facts

Source: DefenseScoop – Air Force drops 14 MOP bombs on Iranian nuclear sites, June 22–23, 2025; DefenseScoop – Joint Chiefs chairman supplies new details about MOP bomb attack, June 26, 2025; DefenseScoop – Battle damage assessment from Iran strikes, July 10, 2025; DefenseScoop – Air Force taps ARA to develop Next Generation Penetrator prototypes, September 8, 2025; Air & Space Forces Magazine – Pentagon to Restock Massive Bombs Dropped by B-2s on Iran, February 12, 2026

These 15 GBU-57 MOP key facts for 2026 document the complete arc of a weapons program from a 2004 DTRA technology demonstration through a 2025 combat debut that immediately validated everything its designers intended — and triggered an immediate replenishment cycle as the USAF moves to maintain its stock of the only conventional weapon capable of threatening the world’s most deeply buried military infrastructure. The 14-bomb employment at Fordow and Natanz consumed a meaningful fraction of the U.S. MOP inventory — and the February 2026 sole-source Boeing contract confirms in the most direct possible terms that the Air Force considers the MOP mission not complete but ongoing. Official USAF language describing the acquisition as critically needed to replenish inventory is the institutional confirmation that a military has used its most powerful conventional weapon in combat and intends to be ready to use it again. The ATACMS reverse-engineering milestone of August 2025 — saving four years of work to eliminate obsolescence in a critical MOP subcomponent — confirms that the program is investing in long-term sustainability even as its production concludes, ensuring that the bombs being replenished will remain serviceable and effective for years of potential future use.

The Next Generation Penetrator program launched in September 2025 with Applied Research Associates and Boeing as the development team is the acknowledgment that even the MOP has limits — and that those limits were partially exposed by Operation Midnight Hammer’s battle damage assessments. DTRA’s confirmed posture after Midnight Hammer — that all facilities were struck as planned and as intended — combined with independent reporting that Fordow suffered severe damage while Natanz and Isfahan may recover faster than anticipated is the operational feedback driving the NGP’s design requirements. The 22,000-pound weight ceiling for the NGP — roughly two-thirds the MOP’s weight — signals that the next penetrator will trade some raw mass for greater accuracy, faster aircraft integration, and compatibility with the B-21 Raider. The NGP’s defining improvement will almost certainly be its fuzing technology: Gen. Caine’s confirmation that each MOP was individually programmed with a unique target impact angle, arrival heading, and fuze setting reveals that the intelligence about the exact depth, structure, and internal layout of the target is as decisive as the bomb itself — and the Large Penetrator Smart Fuze that senses voids and adjusts detonation in real time is the engineering answer to that requirement.

GBU-57 MOP 2026 — Full Technical Specifications

Source: U.S. Air Force GBU-57 Fact Sheet; CBS News – MOP specifications, June 22, 2025; DefenseScoop – Gen. Caine June 26 briefing, June 26, 2025; Wikipedia – GBU-57A/B MOP, updated December 2025; Army Recognition – GBU-57; Defence Today – GBU-57 MOP, June 27, 2025; DOT&E Annual Report 2012 – MOP

The GBU-57 MOP full technical specifications confirm a weapon whose engineering is as much about mass and velocity as it is about explosive power — and where the distinction matters enormously. A conventional bomb achieves destruction primarily through explosive blast radius from a surface or shallow detonation — the bigger the explosive fill, the wider the kill circle above ground. The MOP operates on an entirely different principle: it achieves destruction by converting its 30,000-pound mass into kinetic penetration energy, then detonating its explosive fill deep inside the structure where the surrounding rock and concrete have nowhere to absorb the blast wave except inward through the target’s own tunnel and chamber network. The overpressure and blast energy driving through Fordow’s open tunnels and destroying critical hardware — as confirmed by Gen. Caine — is the operational articulation of this physics: the ventilation shafts that provided Fordow’s air supply became the delivery mechanism for the bomb’s lethal pressure wave throughout the facility’s interior.

The Eglin Steel (ES-1) high-density alloy casing is the engineering achievement that makes this possible. At 1,000+ feet per second terminal velocity, a 30,000-pound steel bomb encounters deceleration forces during penetration that would shatter any conventional bomb body before the weapon reached its design depth. The ES-1 alloy was specifically engineered — developed at Eglin Air Force Base, Florida — to maintain the structural integrity of the penetrator case during impact, preserving the explosive fill and fuze electronics through the extreme deceleration of penetrating reinforced concrete or limestone rock, until the weapon reaches its programmed detonation depth. The Large Penetrator Smart Fuze then does what no fixed-delay fuze could: it reads the structural environment of the penetration in real time — sensing voids when the bomb enters underground chambers, counting material layers as they are penetrated — and triggers detonation at the optimal moment to maximize internal destructive effect. Each of the 14 MOPs dropped on Fordow and Natanz on June 22, 2025 carried a uniquely programmed fuze setting tailored to its specific aim point — the targeting precision of a sniper rifle applied to a 15-ton bomb.

GBU-57 MOP 2026 — Operation Midnight Hammer: Complete Statistics

Source: DefenseScoop, June 22, 23, 26, and July 10, 2025; The War Zone, June 22 and July 10, 2025; CBS News, June 22, 2025; The Aviationist, June 22, 2025; Air & Space Forces Magazine, February 12, 2026; Jerusalem Post, 2025; Wikipedia – GBU-57A/B MOP, updated December 2025; Maxar Technologies satellite imagery, June 22, 2025

The Operation Midnight Hammer MOP employment statistics constitute the most complete verified public record of a bunker-busting munition’s first combat use in military history — made possible by the decision of Gen. Caine and the Pentagon to provide an unusual level of technical detail across two separate press briefings on June 22 and June 26, 2025. The second briefing, specifically dedicated to MOP technical details, is extraordinary in the history of U.S. weapons employment transparency: Caine described the individual bomb fuze programming, the terminal velocity through the ventilation shafts, the specific kill mechanism, and the pilot’s eyewitness account of the detonations — a level of operational detail that confirms the Pentagon wanted the world to understand not just that the MOP had been used, but precisely how it worked and what it did. The specific statistic that 12 of the 14 MOPs were dropped six-per-shaft into Fordow’s two ventilation holes — rather than distributed across the target area — is the most revealing operational detail: the U.S. was not attempting to crater the surface above Fordow but to deliver 12 separate explosive charges into the interior of the underground facility through the only openings available, each bomb driving deeper than the last, the final bombs detonating at maximum depth after the preceding ones had pre-fractured the surrounding rock.

The Maxar satellite imagery released publicly within hours of the strike is the visual confirmation that matches Gen. Caine’s verbal description: the craters visible on the Fordow ridgeline are not from the bombs themselves but from the upward blast and ejecta of weapons detonating inside the mountain — the kinetic energy of the impact forced the bombs underground, and the explosive detonation forced debris and blast energy back up through the shaft path. The grey-blue ash layer across the surrounding area is the combustion residue of 14 bombs’ worth of AFX-757 and PBXN-114 explosive venting from inside the mountain through every available path. The distinction between severe damage at Fordow and the faster potential recovery at Natanz and Isfahan reflects the weapons’ targeting logic: Fordow received 12 MOP bombs specifically directed into its deepest infrastructure; Natanz received only 2 MOPs in conjunction with prior Israeli strikes; and Isfahan received Tomahawk missiles rather than MOPs. The allocation of 86% of the MOP employment to Fordow confirms the strategic priority that drove the entire GBU-57 program’s development: this weapon was built for one specific target, and on June 22, 2025, it was used against exactly that target.

GBU-57 MOP 2026 — Development History & Program Timeline

Source: Wikipedia – GBU-57A/B MOP, updated December 2025; DOT&E Annual Report FY2012 – MOP; Air & Space Forces Magazine – GBU-57 MOP archive; DefenseScoop, June–September 2025; The War Zone, June 2025–February 2026; The Aviationist, June 2025 and February 2026; Boeing / DTRA historical documentation; GlobalSecurity; designation-systems; Grey Dynamics, 2025

The GBU-57 MOP development history and program timeline spans exactly 23 years from the Big BLU program’s initiation in 2002 through the weapon’s combat debut in 2025 — a development arc that includes three separate periods of funding suspension, two accelerations driven by emerging intelligence about Iran’s underground nuclear program, and a continuous cycle of testing and upgrade that produced seven distinct variants between initial fielding and the F/B version used in Midnight Hammer. The 2007–2010 testing period at White Sands and Holloman generated the empirical data that all subsequent MOP modeling and simulation has been built on — and Gen. Caine’s confirmation at the June 26, 2025 briefing that DTRA was able to study how the MOP behaves across specific geographies and structural architectures during that testing program is the most direct confirmation that the 23-year testing investment paid off in operational accuracy on the night of June 22, 2025. The 2009 intelligence revelations about Fordow — the deeply buried uranium enrichment facility carved into a mountain specifically to be protected from air strikes — are explicitly cited by Gen. Caine as the urgency that drove the program’s acceleration in the final years before fielding, confirming that the weapon and the target were effectively developed in response to each other across the decade between 2009 and 2019.

The concluding production status confirmed in February 2026 USAF documents marks the end of a 23-year era in U.S. bunker-busting weapons development. The MOP’s final lot of production will be the $100M+ Boeing replenishment contract triggered by its own combat use in Midnight Hammer, a fitting conclusion to a program that existed specifically to be ready for one type of mission and executed that mission on its first deployment. The NGP’s design requirement of under 22,000 pounds — roughly two-thirds the MOP’s mass — signals that the next generation of deep penetrators will achieve their effect through improved guidance precision, more effective fuzing, and compatibility with the B-21 Raider rather than through additional raw mass. But the MOP’s fundamental contribution — proving that a conventional weapon can penetrate and destroy targets at 200+ feet underground through rock and reinforced concrete — will define the architecture of every hard-target defeat weapon that follows it for decades to come.

Disclaimer: This research report is compiled from publicly available sources. While reasonable efforts have been made to ensure accuracy, no representation or warranty, express or implied, is given as to the completeness or reliability of the information. We accept no liability for any errors, omissions, losses, or damages of any kind arising from the use of this report.

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