B-2 Spirit vs. F-15E: Which Stealth Bomber Dominates with GBU-57 MOP in Precision Strikes?
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U.S. Air Force B-2 Spirit strategic bomber that struck Iranian nuclear facilities with the GBU-57 MOP during Operation Midnight Hammer
* Source: U.S. Air Force photo by Cynthia Griggs
Recent U.S. defense outlets have detailed the bunker-buster weapons and air platforms used in three high-profile actions: Operation Midnight Hammer against Iran on June 22, 2025; Israel’s precision strikes on Hezbollah in Lebanon; and Operation Epic Fury on Feb. 28 of this year, when GBU-57 MOPs were employed against subterranean targets.
First, Israel’s campaign to degrade Hezbollah in Lebanon. On Feb. 7, 2025, The War Zone reported that an Israeli Air Force F-15I delivered multiple GBU-31s—BLU-109 penetrator warheads fitted with JDAM guidance kits—against an underground Hezbollah command post and weapons cache in southern Lebanon, destroying the sites. The strikes followed Israel’s Sept. 27, 2024 precision strike that killed Hezbollah secretary-general Hassan Nasrallah at an underground command center in the Dahieh district south of Beirut, and were aimed at neutralizing remaining Hezbollah stockpiles in southern Lebanon.
The BLU-109 bunker-buster, developed by General Dynamics in 1985 and fielded to the U.S. Air Force, weighs roughly 910 kg (about 2,007 lb), is 2.4 m long, and has a 370 mm diameter. It’s designed to penetrate about 1.22–1.83 m (4–6 ft) of reinforced concrete and detonate on a delayed fuze. The Israeli Air Force primarily used this munition to attack Hezbollah’s underground hideouts in densely populated southern Lebanese neighborhoods.
Next, the U.S. Operation Midnight Hammer on June 22, 2025. Popular Mechanics reported on June 24 that the U.S. Air Force loaded 14 GBU-57 MOPs (Massive Ordnance Penetrator) onto seven B-2 Spirit strategic bombers for strikes on Iran’s Fordow and Natanz nuclear facilities. The MOP is reported to be capable of penetrating roughly 60 meters (about 197 ft) of earth before its fuze triggers; the report said the strikes nearly neutralized the Iranian facilities.
The GBU-57 MOP, developed by Boeing, is a large precision-guided penetrator weighing about 13,600 kg (30,000 lb). It measures roughly 6.2 m in length with a 0.8 m diameter and is fitted with a Large Penetrator Smart Fuze (LPSF). The LPSF senses subsurface structural voids in real time and initiates detonation at the optimal moment. The weapon is engineered to defeat reinforced concrete with compressive strength above 5,000 psi (about 34 MPa), allowing it to put underground tunnel structures out of action.
By contrast, the F-15E tactical fighter—used to carry BLU-109s—lacks stealth and presents a higher acoustic and visual signature. The Northrop Grumman B-2 Spirit, however, combines low observable characteristics with aerial-refueling capability and can carry two GBU-57 MOPs in its internal weapons bay, enabling long-range precision strikes.
On May 4, 2023, The War Zone confirmed that the B-2 Spirit is currently the only operational platform cleared to carry the MOP, though B-52s supported MOP test drops in earlier demonstrations. The outlet also noted that Northrop Grumman’s next-generation stealth bomber, the B-21 Raider, is expected to be able to carry one MOP once fielded.
Meanwhile, on March 11, 2026, The War Zone published an analysis casting doubt on the claimed precision effects of GBU-57 MOP strikes during Operation Epic Fury on Feb. 28 against Iran’s Taleqan-2 facility. Using commercial satellite imagery, analysts questioned the U.S. Joint Chiefs’ June 22 announcement that seven B-2 Spirits dropped 14 GBU-57 MOPs on Fordow and Natanz, suggesting the physical evidence did not fully align with the official account.
Earlier, in 2023, The War Zone assessed that U.S. global precision-strike capability would grow significantly once the B-21 Raider enters service and upgraded variants of the GBU-57 MOP are fielded. On March 11, 2026, the outlet also reported that the B-21 is undergoing aerial-refueling trials at training ranges on the U.S. mainland.
Ultimately, the U.S. Air Force is expected to field a more capable long-range precision-strike force as the B-21 Raider comes online and improved GBU-57 variants are introduced.
* Source: The War Zone (2023.3.4, 2025.2.7, 2025.7.10, 2026.3.11); Popular Mechanics (2025.6.24)
Copyright ⓒ Korea Institute for Military Affairs (www.kima.re.kr)
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