Israel has pushed the US to use its ‘bunker buster’ bomb on Iran. Here’s what the weapon can do
CNN
By Haley Britzky and Lou Robinson, CNN
Washington (CNN) — As President Donald Trump is warming to the idea of using US military assets to strike Iranian nuclear facilities, officials and experts have suggested the US’ 30,000-pound “bunker buster” bomb is the only weapon capable of destroying the Fordow Fuel Enrichment Plant, a facility thought to be key to Tehran’s nuclear program, which is carved into a mountain and extends deep underground.
The GBU-57A/B Massive Ordnance Penetrator (MOP), which has yet to be used operationally, is designed for “reaching and destroying our adversaries’ weapons of mass destruction located in well-protected facilities,” according to a fact sheet from the US Air Force.
The weapon is a 30,000-pound bomb with 6,000 pounds of “high explosives,” said Masao Dahlgren, a fellow with the Center for Strategic and International Studies Missile Defense Project.
It has “really thick, hard shell,” Dahlgren explained, in order for the explosives to withstand the impact of the ground and penetrate to the depths it’s intended to reach.
“There’s the shell and there’s the explosive in the fuse – the explosive needs to be robust enough to not detonate without being fused, the shell needs to be strong enough to go down that far and to hit that hard and to impart enough energy to even go down that far. And then the fuse needs to be hard enough to survive all that, and smart enough to know when to blow up,” Dahlgren said. “It’s a really complex program.”
The exact size of the Fordow Fuel Enrichment Plant is unclear; CNN has reported that that its halls are estimated to be 80 to 90 meters underground. A UK-based think tank, the Royal United Services Institute, said the MOP may not even be able to reach Fordow, saying in a recent report that it would “likely require multiple impacts at the same aiming point to have a good chance of penetrating the facility.”
Fordow could be at the “the edge” of the MOP’s capabilities with only one munition, said Dahlgren.
Testing for the bomb began in 2004 amid the heightened concern about weapons of mass destruction, Dahlgren said. One of the factors that led to its development, he added, were studies that showed bombing a facility’s entrance “wouldn’t generate enough blast pressure to destroy the entire facility.”
“Part of the need for these penetrators is really because it’s hard to just bomb the entrances and get away with it,” Dahlgren said. “You can temporarily slow the progress of a program but not fully destroy things that way.”
In 2009, Boeing won the contract to integrate the weapons system with US aircraft. The Air Force’s B-2 Spirit – a multi-role heavy bomber – is the only aircraft able to employ the bomb operationally.
The B-2, made by Northrop Grumman, is the “backbone of stealth technology,” according to the company. The aircraft flies out of Whiteman Air Force Base, Missouri, and was first publicly displayed in November 1988. The US used B-2 bombers in 2024 to strike the Iran-backed Houthis in Yemen, targeting underground weapons storage facilities.
The bomber – flown by a two-man pilot crew – can fly approximately 6,000 nautical miles without being refueled, according to the Air Force. Its “stealth” capabilities allow it to “penetrate an enemy’s most sophisticated defenses and threaten its most valued, and heavily defended, targets,” the Air Force said.
It’s unclear how many of the munitions the US has in its inventory; in 2009, Boeing delivered 20 of them to the Air Force, which was current as of 2015. Dahlgren estimated there are roughly 30 munitions in the US arsenal.
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