Fordo site had two main ventilation routes into the underground facility — and officials carefully eyed these entry points as a way to target the site.
The deep-penetrating bombs used by the United States to target Iran’s underground nuclear facilities were the result of more than 15 years of intelligence gathering and weapons development, top Pentagon officials said on Thursday.
“These bombs were tailor-made for these targets,” said Defense Secretary Pete Hegseth during a press briefing, alongside Gen. Dan Caine, Chairman of the Joint Chiefs of Staff. Both confirmed the strikes hit exactly as planned.
How the Program Began
General Caine revealed that the development of the GBU-57 A/B Massive Ordnance Penetrator—commonly known as the “bunker-buster”—began after a classified 2009 briefing showed satellite images of heavy construction in Iran’s mountains. That site would later be identified as the Fordo uranium enrichment facility, which became operational the same year.
Caine said two Defense Threat Reduction Agency officers dedicated the next 15 years to studying every detail of Fordo’s construction: “They tracked every piece of machinery going in and out, every pile of earth moved, and the facility’s geology.”
At the time, the U.S. did not have a bomb capable of penetrating Fordo. That gap sparked the Pentagon’s long-term weapons design effort, supported by extensive supercomputer modeling. “Quietly, we became the largest user of supercomputer hours in America,” Caine said.
Inside the Bomb: Precision Built for Deep Impact
The 30,000-pound bomb is made of steel, high explosives, and a time-delay fuse. The fuse is carefully calibrated—the deeper the penetration, the later the detonation. After hundreds of tests on mock underground sites, the weapon was refined to explode inside simulated enrichment chambers and destroy equipment through interconnected tunnel systems.
The Attack on Fordo: Step by Step
Fordo’s facility is protected by two ventilation routes, each with three shafts resembling a pitchfork. Days before the strike, Iran placed concrete slabs over the shafts in an attempt to shield them.
The U.S. responded with a carefully choreographed plan using seven B-2 stealth bombers, each carrying two bunker-buster bombs.
For each ventilation route:
- Bomb 1: Destroyed the concrete slab.
- Bombs 2–5: Dropped down the central shaft at over 1,000 feet per second and detonated underground.
- Bomb 6: Backup, in case of malfunction.
In total, 12 bombs were dropped on Fordo, six per route. Two more targeted Iran’s main enrichment site at Natanz.
“Each bomber crew confirmed detonation by watching the bombs fall from the jet in front,” Caine said. Pilots reported a blinding explosion—“like daylight,” one said.
Did the Bombs Destroy Enriched Uranium?
Despite the Pentagon’s confidence in the operation, uncertainty lingers over whether Iran’s stockpile of highly enriched uranium was present during the strike.
Asked repeatedly about its location, Hegseth declined to confirm, saying: “I’ve seen no intelligence indicating anything was moved or missing.”
A Decade-Long Mission Comes to Fruition
“This mission represents over a decade of precise planning, development, and execution,” Caine emphasized. While he avoided repeating President Trump’s claim that Iran’s nuclear program was “obliterated,” he underscored the strategic success.
“Iran’s nuclear facilities have been destroyed,” Hegseth concluded, though questions remain about the full impact on Iran’s nuclear capabilities.
