GBU-57A/B: No bunker is safe

In one of the most daring escalations in modern warfare, the United States unleashed a pre-dawn surprise attack Sunday (Philippine time) that shattered Iran’s underground nuclear strongholds — thanks to the GBU-57A/B Massive Ordnance Penetrator, or what the military calls the “bunker buster.”

The strikes, carried out by three B-2 Spirit stealth bombers, dropped six bunker-busting bombs on Iran’s most fortified nuclear facilities in Fordow, Natanz and Esfahan. The operation was supported by a volley of 30 Tomahawk cruise missiles fired from submarines lurking in undisclosed waters.

The results? Devastation.

Even Iran’s prized Fordow enrichment facility, buried deep beneath a mountain and protected by Russian-made missile defenses, couldn’t survive the 30,000-pound payload that burrowed into rock before erupting with over two tons of high explosives.

The bomb that changed the battlefield

The GBU-57A/B MOP is not just another bomb — it’s a weapon built specifically for missions like this. Designed to punch through up to 200 feet of reinforced concrete or 60 meters of solid rock, it explodes after breaching the target, demolishing whatever lies beneath.

Guided by GPS and detonated by a delay-fuse system, the MOP was developed by Boeing with one goal in mind: to take out deeply buried facilities that conventional weapons couldn’t touch. Each costs tens of millions of dollars to produce, and as of last reports, fewer than two dozen exist in the U.S. arsenal.

Stealth in the sky

Delivering a bomb that heavy requires an aircraft like no other: The B-2 Spirit, the world’s only stealth bomber capable of carrying the MOP. Costing $2.1 billion each, the B-2 flies thousands of miles undetected, with radar-evading curves and internal weapons bays that hide its payload.

For this mission, each B-2 carried two bunker busters, flying silently across continents under the cover of a carefully staged base “maintenance closure” at Whiteman Air Force Base in Missouri. The real mission: slip under Iran’s radar and cripple the heart of its nuclear program before sunrise.

Why this strike mattered

Until now, Fordow was seen as untouchable. That belief is gone. This was the first known operational use of the bunker buster on a live nuclear facility, changing not only the landscape at Fordow but also the strategic thinking across the region.

Iran’s immediate response has been fury: ballistic missiles rained on Israeli cities within hours, and Tehran vowed revenge against both Washington and Tel Aviv. But the broader message was clear:

No bunker is safe anymore.