The United States struck three of Iran’s nuclear enrichment facilities with the world’s most powerful bunker buster, the GBU-57, increasing interest in the Korean bunker buster ‘Hyunmoo-5’. The GBU-57 is an air-to-ground guided bomb launched from bombers, while the Hyunmoo-5 is a surface-to-surface ballistic missile with a maximum range of about 300 km.
On the 21st (local time), the U.S. military sent six B-2 stealth bombers to Iran’s Fordow nuclear facility and dropped 14 GBU-57 massive ordnance penetrators (MOP). This is the first time GBU-57 has been deployed in actual combat since it was operationalized in 2023.
The GBU-57 is a bunker buster that is 6.1 meters long and weighs 13.6 tons, capable of penetrating concrete structures down to 60 meters underground. The GBU-57 is launched from B-2 bombers and drops down to the target without propulsion assistance.
The U.S. fired multiple rounds of GBU-57 at the same location, a measure to increase penetration capability by digging into the surface. It is akin to a hammer striking a single point multiple times to dig into the ground. The U.S. named its operation against Iran ‘Midnight Hammer’ for this reason.
The nuclear facilities in the Fordow region of Iran are constructed of reinforced concrete, located 80 to 90 meters underground. Israel has also reportedly requested U.S. support with GBU-57 due to the difficulty of destroying the facilities.
Korea’s Hyunmoo-5 has a warhead weight of up to 8 tons, more than three times greater than the GBU-57 (2.4 tons). The actual appearance of the Hyunmoo-5 was first unveiled to the public during last year’s Armed Forces Day ceremony in October. At the time, Kim Yo-jong, the deputy director of the Workers' Party of Korea and sister of North Korean leader Kim Jong-un, downplayed it as “a weapon that is just unnecessarily large,” but there are assessments in the market that it could provoke North Korea.
The Hyunmoo-5 ascends to 1,000 km before accelerating to over Mach 10 with a rocket propellant, providing excellent penetration capability. Its high speed makes it difficult for existing missile defense systems to intercept. The warhead’s destructive power is significant, but the kinetic energy generated from the hyper-fast drop can create artificial earthquakes capable of annihilating underground bunkers. There are also assessments that the Hyunmoo-5 has superior explosive power.
The Hyunmoo-5 can destroy bunkers located 100 meters underground. It is reported that our military has plans to annihilate Pyongyang with 20 to 30 Hyunmoo-5s if North Korea launches an invasion.
The U.S. GBU-57 can strike anywhere in the world when mounted on a bomber, while the Hyunmoo-5 requires a launch vehicle, restricting its mobility. In contrast, the GBU-57 is heavy, allowing only two to be carried on a bomber, whereas the Hyunmoo-5 can extend its range to over 5,000 km if the warhead weight is reduced.
The annual production scale of the GBU-57 is reported to be 20 units, while the Hyunmoo-5’s production scale is about 70 units per year. Development and test launches are said to be complete, with production handled by Hanwha Aerospace.