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The U.S. Air Force has awarded a two-year contract to Applied Research Associates (ARA) to develop the Next Generation Penetrator (NGP), a successor to the 30,000-pound GBU-57 Massive Ordnance Penetrator (MOP). Boeing will provide the tail kit and integration support.

ARA, based in Albuquerque, New Mexico, confirmed the deal, saying it will serve as the system design agent for the new weapon. The Air Force Life Cycle Management Center’s Munitions Directorate at Eglin Air Force Base is overseeing the project.

“This effort will evaluate capabilities against hard and deeply buried targets that pose critical challenges to U.S. national security,” ARA said in a statement.

The MOP is the largest conventional bomb in the U.S. arsenal, designed specifically to destroy hardened and deeply buried targets. Weighing 30,000 pounds, it combines mass and advanced fusing technology to penetrate reinforced concrete and rock before detonating. Only the B-2 Spirit stealth bomber is currently capable of carrying the weapon, with a loadout of two bombs per mission.

The MOP entered the spotlight earlier this year when U.S. forces used it for the first time in combat against Iran’s Fordo nuclear enrichment facility. During Operation Midnight Hammer, six B-2 bombers dropped 12 MOPs on two designated points, with successive bombs digging deeper to reach underground targets. The operation highlighted both the weapon’s destructive capacity and the challenges of striking deeply buried facilities.

Air Force officials have acknowledged that lessons from this strike are shaping the development of the NGP. Senior leaders argued that MOP’s combat debut reinforced the strategic importance of having a conventional option against targets that might otherwise be reachable only with nuclear weapons.

Design Goals and Requirements

The Air Force outlined its vision for the new bunker-buster in a February 2024 request for information. The NGP’s warhead must not exceed 22,000 pounds, making it lighter than the current MOP but still capable of blast, fragmentation, and penetration effects.

Accuracy is a key requirement. The Air Force specified that the bomb should be able to strike within 2.2 meters of a designated target 90 percent of the time. This demand is particularly challenging in environments where GPS signals are jammed, degraded, or denied, a growing threat from advanced adversaries.

The contract requires ARA to produce and test 10 subscale prototypes and three to five full-scale warheads within 18 to 24 months. These will be tested against hard and deeply buried targets to validate performance.

Boeing’s Role and Integration

Boeing, which designed the MOP’s KMU-612/B tail kit containing its GPS-assisted inertial navigation system, will again take on responsibility for the tail unit of the NGP. The company will also contribute to guidance, navigation, and control technologies designed to ensure accuracy in denied GPS environments.

Advanced fuzes are another priority. The Air Force has emphasized the importance of fuze systems that can “count” levels underground and sense voids to maximize destructive potential. Such technology was critical to MOP’s effectiveness and is expected to be further refined for NGP.

ALSO READ: How the US targeted Iranian nuclear sites with Bunker Buster bombs

The Air Force has developed the MOP and NGP programs to address a persistent challenge: the ability of adversaries to conceal high-value military or nuclear assets in hardened underground facilities. Nations such as Iran, North Korea, China, and Russia have invested heavily in such complexes, including command bunkers, missile silos, and nuclear labs built deep under mountains or reinforced concrete.

Traditional precision-guided munitions, while effective against above-ground or lightly buried targets, are largely ineffective against these hardened facilities. Even nuclear-capable cruise missiles would struggle without producing radioactive fallout. The MOP, and now the NGP, offer a conventional means to neutralize these targets.

The Fordo strike demonstrated one usage case: delaying or destroying a nuclear program by targeting enrichment facilities too deep for conventional bombs. Other scenarios could include striking underground ballistic missile storage, command-and-control bunkers designed to withstand nuclear strikes, or tunnel networks used by hostile forces.

The Air Force also views the NGP as critical in a high-end fight against a peer competitor. In a conflict with China, for example, underground bases in mountainous terrain could host key assets, from missile launchers to command posts. An NGP capable of striking those facilities from a stealth bomber at long range would provide a decisive edge.

The Role of Bombers

Currently, only the B-2 stealth bomber is cleared to carry MOPs, but the aircraft is aging and limited in number. The B-21 Raider, expected to enter service later this decade, is smaller and will be able to carry only one MOP instead of two. That limitation adds urgency to the NGP program, which is expected to be lighter and potentially more versatile.

If designed effectively, the NGP could allow the B-21 to hit underground targets with fewer aircraft than would otherwise be required. A future standoff-capable version, for instance, one with a rocket motor, could further extend bomber survivability by allowing strikes from outside enemy air defense ranges.

Strategic Implications

General David Allvin, Air Force Chief of Staff, told lawmakers in June that the service cannot assume adversaries will remain vulnerable to today’s weapons. “It might be something different than the GBU-57, some advancement based on what the enemy might do,” Allvin said.

“This is not a static environment,” he added. “Now that we know that it was successful, I’m pretty sure that people who are potential adversaries might look at that and they may adapt.”

The Air Force has already begun replenishing its MOP stockpiles and upgrading the current design. Officials have stressed that MOP will remain in service even after the NGP is introduced, ensuring a layered arsenal of penetrator weapons.

Much remains undisclosed about the NGP program, including the contract’s value and the precise timeline for full operational capability. But the Air Force expects to have its first prototypes ready within two years, with testing to follow.

If successful, the NGP will represent a major step in the U.S. effort to sustain its ability to hold hardened and deeply buried targets at risk — a capability viewed as essential in deterring adversaries and preserving strategic options short of nuclear use.