Could The US Use GBU-57 Bunker Buster On Iran’s Nuclear Facility? What Makes This Bomb Unique

Curated By :

News Desk

News18.com

Edited By:

Karishma Jain

Last Updated:

June 18, 2025, 22:21 IST

The spotlight is on a US bomb never used in combat, the 30,000-pound GBU-57 bunker buster, potentially the only conventional weapon capable of reaching Iran’s Fordow nuclear site

 

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As tensions rise between Israel and Iran over Tehran’s suspected nuclear ambitions, attention has shifted to one of the most powerful weapons in the American arsenal — the GBU-57A/B “bunker buster" bomb. Developed to destroy deeply buried and heavily fortified targets, this precision-guided weapon may be the only conventional option capable of neutralising Iran’s Fordow nuclear facility, hidden under a mountain near Qom.

 

In this photo released by the US Air Force on May 2, 2023, airmen look at a GBU-57, or the Massive Ordnance Penetrator bomb, at Whiteman Air Base in Missouri. (U.S. Air Force via AP, File)

In this photo released by the US Air Force on May 2, 2023, airmen look at a GBU-57, or the Massive Ordnance Penetrator bomb, at Whiteman Air Base in Missouri. (U.S. Air Force via AP, File)

Israel does not possess the GBU‑57 or the B‑2 Spirit stealth bomber required to deliver it. For this reason, some observers argue that the US could be drawn into the conflict, should a strike on a hardened site like Fordow be deemed necessary. Yet, using this weapon would represent a major shift — not just militarily, but diplomatically and regionally — signalling that the conflict has entered a far more dangerous phase.

 

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What Is The GBU-57 Bunker Buster Bomb And Why Was It Built?

 

The GBU-57A/B Massive Ordnance Penetrator, or MOP, is the most advanced bunker buster bomb ever built. While the term “bunker buster" broadly refers to any munition designed to penetrate hardened targets, the GBU-57 stands apart for its sheer size, power, and specificity.

 

Weighing nearly 30,000 pounds and stretching over 20 feet in length, the bomb is engineered to breach deep earth or reinforced concrete before detonation. It carries more than 5,000 pounds of high explosives and can penetrate up to 200 feet of earth or 60 feet of concrete, a depth unmatched by any conventional bomb.

 

Its casing, made from a specialised high-strength steel alloy, is built to survive immense pressure upon impact. Its guidance system, enabled by GPS-aided inertial navigation, ensures accuracy against fortified underground bunkers, including those surrounded by mountainous terrain.

 

Why Is The GBU-57 Relevant Now? Understanding The Fordow Nuclear Facility

 

At the centre of the current speculation is Iran’s Fordow Fuel Enrichment Plant, located near the city of Qom. The facility is believed to be buried deep within a mountain and is reportedly engineered to withstand conventional airstrikes. While Israeli officials claim that Fordow is being used to enrich uranium to levels approaching weapons-grade, Tehran has repeatedly denied pursuing a nuclear weapons programme.

 

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Fordow’s heavily fortified location makes it nearly impervious to standard munitions. Military analysts believe that only a precision-guided, deep-penetration weapon like the GBU-57 Massive Ordnance Penetrator could realistically damage the site without resorting to nuclear force.

 

In an interview with ABC News, retired US Marine Corps Colonel and defence analyst Steve Ganyard said the bomb was designed for exactly such scenarios: “You make sure you save them for places like Iran and North Korea because you don’t need something that goes that deep [in normal circumstances]," he noted. That is why it has come back into global focus amid the escalating Israel-Iran conflict.

 

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Could The US Use GBU-57 In A Strike Against Iran?

 

Currently, only the United States possesses both the GBU-57 and the B-2 Spirit stealth bomber, the only aircraft capable of carrying the bomb. While Israel has the military expertise and aerial capabilities to conduct precision strikes, it lacks both this specific munition and the required delivery platform.

 

The B-2 stealth bomber, based at Whiteman Air Force Base in Missouri, US, has been tested carrying two GBU-57 bombs, which together make up a 60,000-pound payload. A hypothetical mission to Iran would take around 15 hours, depending on the flight path and aerial refuelling logistics.

 

That said, authorising a US strike on Iranian soil would represent a serious escalation, likely drawing Washington directly into a wider regional conflict. US President Donald Trump has voiced support for Israel’s operations and warned Iran repeatedly, but he has not publicly committed to using the GBU-57.

 

Has The GBU-57 Ever Been Used In Combat?

 

Despite its development starting in 2004 and successful tests in later years, the GBU-57 has never been used in an actual combat mission. According to Steve Ganyard, the bomb is not intended for large-scale destruction. “It wouldn’t be a massive blast," he said. “It would penetrate the ground and shoot up some debris, but it won’t be a massive cloud."

 

The weapon was built for strategic deterrence, not everyday battlefield use. That’s also why its stockpile is believed to be relatively small — at least 20 were delivered by Boeing by 2015, though the current number remains classified.

 

What Would Be The Consequences Of Striking A Nuclear Facility Like Fordow?

 

Striking a nuclear facility, whether operational or inactive, entails significant risks, not just to military stability but to civilian safety, environmental integrity, and global non-proliferation norms. The International Atomic Energy Agency (IAEA) has explicitly warned against such actions. In a statement issued on June 13, IAEA Director General Rafael Mariano Grossi said, “Such attacks have serious implications for nuclear safety, security and safeguards, as well as regional and international peace and security."

 

While Grossi did not refer to any specific site, his remarks followed reports of military activity targeting nuclear-related infrastructure.

 

Though the current status of uranium enrichment at Iran’s Fordow facility is disputed—Iran denies pursuing a nuclear weapon—analysts note that the site is designed to house advanced centrifuges and operate in highly fortified conditions. A strike using the GBU-57 Massive Ordnance Penetrator could potentially disrupt sensitive systems.

 

According to a 2021 report from the Carnegie Endowment for International Peace, damage to such facilities carries risks of localised radioactive contamination, particularly if enriched material is present and containment structures are compromised. Experts also warn of potential Iranian retaliation, whether against American interests in the region, Israeli territory, or commercial shipping routes such as the Strait of Hormuz.

 

Is The GBU-57 A Tactical Weapon Or Political Signal?

 

While the GBU-57 is a military asset, it also serves as a strategic message. It is, in essence, a demonstration of what the US can do without crossing into nuclear warfare. Its mere existence raises the bar for any adversary trying to shield sensitive infrastructure.

 

But with that power comes consequence. The use of a MOP against a nation like Iran, particularly on a nuclear site, would mark a dangerous precedent. It could encourage other countries to build even deeper and more secure underground bunkers, triggering a new kind of arms race not in missiles, but in mountains.

 

There’s also a diplomatic cost. The Trump administration, like its predecessors, has walked a fine line — supporting Israel while calling for restraint and de-escalation. A strike using the GBU-57 would almost certainly draw condemnation from Tehran and its allies, and could derail fragile backchannel negotiations over Iran’s nuclear future.