The US military is restocking its GBU-57 MOP (Massive Ordnance Penetrator) bunker buster bombs that were used to hit Iran’s nuclear facilities during ‘Operation Midnight Hammer’ last year.
The US Air Force (USAF) documents have revealed that the service is in the process of finalising a $100 million deal with Boeing to supplement its arsenal of GBU-57 MOPs, as disclosed in partially redacted documents that were published on February 12, 2026.
The MOPs were used to strike Iran’s Fordow and Natanz nuclear sites on June 22, 2025, when the US launched Operation Midnight Hammer following Israel’s 12-Day War with Iran. This marked the official debut of these bunker-busting bombs, more than two decades after they were inducted into service in 2010.
As part of the operation, about seven B-2 Spirit bombers were used to drop 14 GBU-57 MOPs, with each bomber carrying two munitions.
Justifying the sole-source purchase of the GBU-57 MOP, the Air Force document stated that, since the US military firm Boeing is the only company producing the bunker buster bomb.
The redacted document stated that the contract to any other bidder “would result in unacceptable delays” and jeopardise the Air Force’s preparedness, adding that the defence giant has “uniquely acquired expertise over a period of 18 years of adapting this specialised weapon to meet evolving mission needs as MOP transitioned from proof-of-concept to Full Operational Capability.” Further, it added, “This action is essential to restore operational readiness … and ensure Air Force Global Strike Command (AFGSC) possesses the necessary assets to support strategic contingency war plans for all Combatant Commands (COCOMs).”
Notably, the document did not disclose how many of these bombs the USAF intends to buy or the cost breakdown of each unit.
The exact number of GBU-57 Massive Ordnance Penetrator (MOP) bombs in the US Air Force’s inventory is classified. However, several sources state that the service had at least 20 GBU-57s in service as of the end of 2015.
The production has continued since, and the actual number may have surged, but there has been little indication of additional procurement in the years leading up to 2025, when the weapon made its debut.
The expenditure of about 14 GBU-57 bombs during Operation Midnight Hammer has prompted a sole-source contract, with deliveries projected to begin in January 2028. The USAF states in the documents that the purchase is “critically needed to replenish the inventory of GBU-57s expended during Operation Midnight Hammer.”
Designed to destroy Hard and Deeply Buried Targets (HDBTs), such as command centres, subterranean laboratories, and chemical, biological, and nuclear facilities, the GBU-57 MOP was created in the early 2000s by Boeing and the Defence Threat Reduction Agency (DTRA).
A data sheet issued by the Air Force defined the MOP as “a weapon system designed to accomplish a difficult, complicated mission of reaching and destroying our adversaries’ weapons of mass destruction located in well-protected facilities.”
The most potent non-nuclear bomb in the US arsenal, the MOP weighs 30,000 pounds (about 13,600 kilograms), has a 5,740-pound (about 2,600-kilogram) warhead, and is more than 20 feet long. It can pierce up to 200 feet into reinforced concrete or 60 feet into unreinforced concrete. The kinetic hit delivers 800 to 900 megajoules of kinetic energy.
Operation Midnight Hammer
According to independent reports, Fordow sustained significant damage, but Natanz and Isfahan were less severely affected and are expected to recover sooner than the US officials may have anticipated.
The mission also demonstrated the MOP’s limits, especially its enormous size, restricted aircraft compatibility, and the purported difficulty in breaching ultra-hardened targets.
The US is already replacing the MOP with the Next Generation Penetrator (NGP). The new-generation bunker-buster bomb will be compatible with the B-21 Raider, the US’s next-generation stealth bomber, which is planned as a replacement for the B-2 bomber, as previously explained in detail by the EurAsian Times.
For now, the purchase of the MOP is likely aimed as a stopgap solution until the new Next-Generation Penetrator, or NGP, is inducted into service.
The NGP is envisioned as a more advanced version of the GBU-57 MOP. It can also have an attached rocket booster for stand-off strike capabilities, and the ability to deliver precision strikes within a Circular Error Probable (CEP) of 2.2 meters, in both GPS-aided, degraded, and denied environments.
In September 2025, the Air Force awarded a contract for the NGP to Applied Research Associates (ARA), with Boeing as a partner, to lead development as the system design agent.
This includes producing prototypes, including approximately 10 sub-scale test articles and 3–5 full-scale warhead models. The contract emphasises an accelerated timeline, targeting delivery of these prototypes within 18–24 months of award, which means between March and September 2027.
Nonetheless, the NGP is still in the early development phase, with no publicly disclosed firm date for achieving initial operational capability (IOC) or full operational status, making an MOP purchase a requisite for the USAF, which is dealing with a naturally fortified enemy like Iran.
The recent GBU-57 replenishment contract has been labelled the final major procurement of MOPs before transitioning to the NGP, described as a “similar MOP-like capability” but with “superior technology.”
In addition to the NGP, the USAF is also considering a Global Precision Attack Weapon (GPAW) bunker-buster bomb, which is small enough to fit in the F-35’s internal weapons bay.
Separately, the service has also begun the process of inducting the precision-guided 5,000-pound-class bunker buster bomb, the GBU-72/B/B. The bomb was first used in a combat situation against the Houthis militia in Yemen in 2024.
For now, the timing of the document and the said purchase of MOP is significant as it comes amid the looming threat of another war between the US and Iran.
US-Iran Tensions
Last week, the US President Donald Trump said that he insisted that nuclear talks with Iran must continue in a meeting with Israeli Prime Minister Benjamin Netanyahu, but warned that action will be taken if a nuclear deal is not reached.
The Pentagon has since ordered the USS Gerald R. Ford carrier to deploy from the Caribbean to the Middle East area of responsibility.
In a speech in Jerusalem on February 15, 2026, Israeli Prime Minister Benjamin Netanyahu said that any nuclear agreement with Tehran must include a requirement that Iran give up all of its enriched uranium and be prohibited from enriching any more.
“The first is that all enriched material has to leave Iran,” he said. “The second is that there should be no enrichment capability – not stopping the enrichment process, but dismantling the equipment and the infrastructure that allows you to enrich in the first place”.
Netanyahu also demanded that Tehran’s nuclear program be subject to ongoing inspections. “There has to be real inspection, substantive inspections, no lead-time inspections, but effective inspections for all of the above,” he was quoted as saying.
Earlier, Netanyahu was reportedly pressuring Trump to seek a deal that would put an end to Iran’s nuclear enrichment, restrict its ballistic missile program, and cease the sustained support for proxy organisations like Hamas and Hezbollah.
While the Iranian government has offered to scale back its nuclear program for relief from international sanctions, President Masoud Pezeshkian warned that his country would “not yield to their excessive demands.”
In fact, Iran believes that zero enrichment violates its rights under the nuclear non-proliferation treaty and is considered a red line by the Khomenei regime.
Over the weekend, US Secretary of State Marco Rubio said that US President Donald Trump “prefers diplomacy and an outcome of negotiated settlement” over direct attacks on Iran. However, a massive military build-up is nonetheless underway in the region, as recently explained in detail by the EurAsian Times, signalling intent to go to war.
When asked about the plans for a possible protracted American military action, White House spokesperson Anna Kelly said, “President Trump has all options on the table with regard to Iran.”
“He listens to a variety of perspectives on any given issue, but makes the final decision based on what is best for our country and national security,” Kelly emphasised.
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