While the GBU-28 is one of Israel’s most powerful weapons—and one of America’s best bunker busters—the system simply cannot penetrate the depths at Fordow.
The ongoing Israel-Iran conflict, which escalated into open warfare last week under the imprimatur of Israel’s “Operation Rising Lion,” has brought significant attention to the advanced weaponry employed by the Israeli Air Force (IAF). Among the most prominent of these systems is the GBU-28, a 4,000 to 5,000-pound laser-guided “bunker-busting” bomb, which has been a critical asset in Israel’s arsenal.
Indeed, many sources indicate that this bomb has been used repeatedly by the IAF to try to destroy the hardened Iranian nuclear facilities in places like Fordow.
The History of the GBU-28 Bomb
Also known as Guided Bomb Unit-28, the GBU-28 was originally developed by the United States during Operation Desert Storm in 1991 to address the need for a weapon capable of penetrating hardened targets such as Iraqi command-and-control bunkers deep underground. Designed by engineer Albert L. Weimorts at Eglin Air Force Base, the bomb was created in a remarkably short three-week timeline, showcasing rapid innovation under wartime pressure.
The initial GBU-28 was constructed within an eight-inch artillery barrel, but later versions incorporated the purpose-built BLU-113 bomb body, manufactured by National Forge in Pennsylvania.
Coming in at a weight of approximately 4,700 pounds, the GBU-28 is equipped with a laser-guidance system, which allows it to home onto targets illuminated by a laser designator. Enhanced versions incorporate inertial navigation (INS) and GPS guidance, improving accuracy in adverse conditions. The bomb’s BLU-109/B warhead is designed to penetrate up to 16 feet of solid concrete—or over 160 feet of earth—before detonating, triggered by a short-delay fuse that ensures explosion at optimal depth.
Testing was done at the Tonopah Test Range in 1991. The testing demonstrated the GBU-28’s ability to smash through 22 feet of reinforced concrete while retaining significant kinetic energy, making it ideal for targeting underground bunkers and fortified facilities.
Israel acquired 100 GBU-28s in 2005, with deliveries accelerated in 2006 and 55 units delivered by 2009. The acquisition was partly motivated by concerns over Iran’s nuclear program, with a leaked 2009 diplomatic cable suggesting the bombs be used against Iran’s suspected nuclear weapons facilities. The GBU-28’s ability to penetrate hardened structures makes it a key tool for Israel, whose air force operates advanced platforms like the F-15I Ra’am and F-16I Sufa, capable of delivering such heavy ordnance.
During Desert Storm, GBU-28s were dropped by US F-111F aircraft, targeting Iraqi bunkers. In 2003, 12 years later, a single GBU-28 was used against Saddam Hussein’s forces in Operation Iraqi Freedom. Israel’s use of the GBU-28 is less documented, but includes unconfirmed reports of its deployment during 2008-2009 Gaza War and confirmed extensive use in its 2021 Gaza operation, codenamed “Guardian of the Walls.”
These operations highlight the bomb’s role in targeting fortified structures such as tunnels and underground command centers—a capability directly relevant to Israel’s objective in its current conflict with Iran.
The GBU-28’s Role in the Israel-Iran War
The Israelis have a stated objective of dismantling Iran’s nuclear weapons and missile programs. Iran’s nuclear facilities, particularly its Fordow Fuel Enrichment Plant, are buried deep beneath a mountain near Qom, designed to withstand conventional airstrikes.
While Israel has targeted sites, like Natanz and Isfahan, Fordow remains a formidable challenge due to its depth and fortifications. Indeed, the geology at Fordow has been known to complicate the normal operations of fuses on bunker buster bombs.
While the GBU-28 is one of Israel’s most powerful weapons—and one of America’s best bunker busters—the system simply cannot penetrate the depths at Fordow. That is why the Trump administration is seriously considering intervening with American warplanes, notably the B-2 Spirit long-range stealth bomber, which can deploy the mighty GBU-57 30,000-pound Massive Ordnance Penetrator (MOP)—likely far more effective at penetrating the hardened depths of the Fordow nuclear facility in Iran.
Destroying Fordow has now become the Holy Grail of Israel’s anti-nuclear weapons campaign in Iran. The Israelis simply cannot destroy this hardened facility, no matter how many times they have hit it. In response, they want the Americans to finish it off with their ordinance—and it looks increasingly as though the Trump administration is ready to do that.
About the Author: Brandon J. Weichert
Brandon J. Weichert, a Senior National Security Editor at The National Interest as well as a contributor at Popular Mechanics, who consults regularly with various government institutions and private organizations on geopolitical issues. Weichert’s writings have appeared in multiple publications, including the Washington Times, National Review, The American Spectator, MSN, the Asia Times, and countless others. His books include Winning Space: How America Remains a Superpower, Biohacked: China’s Race to Control Life, and The Shadow War: Iran’s Quest for Supremacy. His newest book, A Disaster of Our Own Making: How the West Lost Ukraine is available for purchase wherever books are sold. He can be followed via Twitter @WeTheBrandon.
Image: Wikimedia Commons.
