Summary and Key Points: The U.S. military’s increased concentration of B-2 bombers at Diego Garcia, combined with President Trump’s warnings to Iran, suggests a possible strike on Iran’s nuclear infrastructure.
-While Israel’s air force has faced limitations in targeting Iran’s deeply buried facilities, the U.S. B-2 Spirit bombers are equipped with the GBU-57 Massive Ordnance Penetrator, a 27,000-pound bomb designed to penetrate hardened underground targets.
B-2 Bomber. Image Credit: Creative Commons.
-The concentration of B-2s, along with aerial refueling support, positions the U.S. Air Force to potentially strike Iran’s nuclear facilities. However, even with this capability, completely neutralizing Iran’s nuclear program would be challenging due to its resilience and dispersed nature.
B-2 Bombers Close to Iran with a Goal in Mind?
Iran’s defensive posture remains in deep disarray following Israeli airstrikes late last year.
Not only are Iranian proxies Hamas and Hezbollah severely battered, but the Assad family no longer rules Syria. Meanwhile, after the strikes, all four of Iran’s Russian-supplied S-300 air defense batteries are reportedly kaput.
There is a unique window of opportunity right now in which Iran is just about defenseless. And, the argument among some Iran hawks in the West goes, it might never be more feasible to—quite literally—blow up Iran’s nuclear program.
Limitations and Operational Realities
Two factors limit what Israel could achieve on its own: less-capable bunker-buster penetration munitions and fewer, lower-capacity tanker aircraft.
Last year, the Israeli Air Force struck a series of buildings in Beirut, taking out Lebanese Hezbollah leader Hassan Nasrallah and other senior leaders. During that strike, the IAF reportedly dropped 60 to 80 Joint Direct Attack Munitions (JDAMs), free-fall bombs equipped with GPS and maneuvering surfaces that turn them into precision weapons.
During those operations, dozens of bunker-busting JDAM bombs pummeled the underground complex where Hezbollah leaders had been holed up. While the strike was a success, the fact that 60 to 80 munitions were needed to penetrate the building complex and underground fortifications below indicates a limited capability, especially if it is needed against more deeply buried, hardened facilities, which those housing Iran’s nuclear infrastructure surely are.
Another limitation imposed on the Israeli Air Force is the country’s air-to-air refueling capacity. While Israel does have a fleet of tankers, those aircraft are modified commercial airliners that are many decades old. In addition to questions of readiness and fuel capacity, their survivability in a contested aerial environment would be poor.
Diego Garcia and Those B-2 Bombers
Recent satellite imagery, open-source data, and reporting indicate that a significant portion of the U.S. Air Force’s B-2 Spirit stealth bomber fleet is massing at Diego Garcia, an island in the Indian Ocean that hosts a British military installation.
Crucially, Diego Garcia is beyond the reach of even Iran’s longest-range missiles.
Over the weekend, U.S. President Donald Trump told NBC News’ Kristen Welker that “If they [Iran] don’t make a deal, there will be bombing.” Trump added that “it will be bombing the likes of which they have never seen before.” Iran appears to be readying a military response should an attack on the country go forward.
Though it is unclear just how many B-2 Spirits are at Diego Garcia, there may be four, and possibly as many as seven of the stealthy strategic bombers. The entire fleet of B-2 bombers is just 19.
B-2 Bomber. The B-21 Raider will look very similar. Image Credit: Creative Commons.
The bombers have been joined by more than a dozen other aircraft flown in from the United States and Europe, including a number of aerial refueling aircraft and C-17 cargo planes. The latest fleet-tracking reports from USNI News show that in addition to the Harry S. Truman Carrier Strike Group in the Red Sea, the USS Carl Vinson, a Nimitz-class aircraft carrier, is currently off the coast of the Philippines en route to U.S. Central Command.
The Bomb
One of the more intriguing aspects of this concentration of forces is one of the weapons the B-2 is certified to drop: the GBU-57 Massive Ordnance Penetrator.
The GBU-57 MOP is a 27,000-pound bunker-busting bomb designed to penetrate through the earth, punch through reinforced concrete, and detonate deep underground. It is optimized for hardened, deeply protected targets—the kinds of targets that make up Iran’s underground nuclear infrastructure. And the B-2 Spirit is the “only aircraft in the Air Force inventory programmed to employ the MOP.”
The GBU-57 recently underwent a U.S. Air Force modernization program, one that “concluded subscale lethality testing, conducted an end-to-end full-scale test of the smart fuze, and completed testing of a fix to an integration issue with the B-2.” However, the Air Force has not yet funded the final, full-scale tests to integrate the Large Penetrator Smart Fuze onto the entirety of the GBU-57 stockpile.
The fuze would be able to detect voids in the earth before coming to rest—think large tunnels, or underground rooms—and detonate when it is in a void to maximize blast impact.
Postscript
The U.S. Air Force is arguably the best-positioned organization in the world to take out the Iranian nuclear program using force. Using stealth bombers’ specialized bunker-busting munitions against hardened underground facilities, which are located thanks to detailed intelligence, the destruction of the program would seem likely, especially when considering the additional options provided by the participation of the Israeli Air Force.
B-2 Bomber. Image Credit. U.S. Air Force.
Though an attack by these air forces working in tandem would likely achieve the destruction of Iranian nuclear infrastructure in the immediate term, completely neutralizing it in the long term would be difficult, as the Iranian nuclear program is designed with resilience in mind. Dispersed facilities—and the dispersal of the institutional knowledge necessary to further the program—mean it would likely survive.
About the Author: Caleb Larson
Caleb Larson is an American multiformat journalist based in Berlin, Germany. His work covers the intersection of conflict and society, focusing on American foreign policy and European security. He has reported from Germany, Russia, and the United States. Most recently, he covered the war in Ukraine, reporting extensively on the war’s shifting battle lines from Donbas and writing on the war’s civilian and humanitarian toll. Previously, he worked as a Defense Reporter for POLITICO Europe. You can follow his latest work on X.
