Deep Down Under: The Battle Against Iran's Buried Bunkers
- Geeky Gernot
- 4 Min Read
High-Powered GBU-57 Destined for Penetrating Iran's Subterranean Fortifications - Powerful Bomb, GBU-57, Designed to Penetrate and Destroy Deepest Iranian Bunkers
With Israeli domination over a significant part of Iran's airspace, the enemy's air defenses crumble like a great wall. But, the Israelis are left wanting more - two crucial war goals remain unfulfilled. The Iranian facilities for uranium enrichment continue to operate, and the vast warehouse of drones and missiles go unscathed. The reason? Iran's clerical regime hides these vital facilities deep underground, fortified in dugout bunkers and mine-like tunnels.
Take Fordo, located up to 90 meters beneath the earth, reinforced with multiple layers of concrete and a decentralized tunnel system. This deep bunker escapes the reach of Israel's bombs, at least partially. Israel can bomb the exposed aboveground facilities, block their entrances, and cripple their access roads. But the real "bunker" remains out of reach. This means the facilities can only be blocked for a limited time, but in the long run, they can easily be reactivated, especially during a ceasefire.
Bombs of Limited Power
Normal bombs, long-range weapons like cruise missiles, and rockets lack the power to penetrate this type of deep bunker. Their warheads aren't strong enough to crack the armor-plated exterior or cause enough havoc beneath the earth. Special bunker-busters, such as the German Taurus or Israel's SPICE-2000 with a 900 kg warhead, also fall short. Russia faces a similar problem in Ukraine, where Cold War-era, bombproof factory plants resist bombardments.
However, there are weapons designed to tackle such deep bunkers. Essentially, there are three approaches.
- Surface Explosions: Massive explosions generate a ripple effect on the surface, momentarily destabilizing structures underneath. Examples include the "Mother of All Bombs" (MOAB) from the USA and Russia's "Father of All Bombs." However, these weapons only affect surface-near targets and do not work arbitrarily deep. These bombs may excel in a dynamic land war, as prolonged access and air supplies can be effectively disrupted.
- Ground-Piercing Bombs: These bombs penetrate the earth, explode inside, and cause local seismic disturbances. The U.S.-made GBU-28 "Deep Throat," designed to penetrate about 6 meters of concrete, falls into this category. It was used during the Gulf War in 1991, but its effectiveness on extremely deep facilities is limited.
- Penetrators: The GBU-57, nicknamed Massive Ordnance Penetrator (MOP), carves its way through the earth by sheer kinetic power. It can burrow deep, up to 60 meters of soil or 8 meters of reinforced concrete, and then pierce conventional armor. The bomb's warhead contains about 2.4 tons of explosives, which is devastating in a confined underground space.
The GBU-57's Kinetic Punch
The GBU-57, in service since 2011, was refined for facilities like Fordo in 2016. Each bomb costs around $3.5 million, and the U.S. has only 20 of them. Developed from experiences with the GBU-28 in the Gulf War, the GBU-57 is not your ordinary bunker buster.
The GBU-57 initially penetrates the ground through its high kinetic energy. This kinetic energy comes from its massive size and speed. However, the bomb's sheer mass poses a challenge - it weighs 14 tons, rendering it unable to be deployed by combat aircraft. Only strategic bombers, like the U.S.'s B-2 Spirit, are capable of carrying this hefty ordnance. Israel lacks similar heavy-duty aircraft and would rely on direct U.S. involvement in the war for support. Moreover, the GBU-57 needs to be dropped from a relatively short distance before it can guide itself to its target.
A Last Resort?
While powerful, the GBU-57 has limitations - penetration is not infinite, and its destructive force is localized. Chambers under a mountain will not be reached by it, and while it can destroy a bunker room or cavern, sprawling facilities with multiple compartments may only see portions destroyed. The weapon's modus operandi is well-known, allowing Iran to ensure its facilities are designed to resist an attack by the GBU-57 or at least limit the damage. To completely neutralize Iran's entire arsenal, a significant number of attacks would be needed, as the U.S. only possesses around 20 of these bombs. But for symbolic attacks on key facilities like Natanz and Fordo, the GBU-57 could be an option.
In 2024, the Israelis employed a method akin to the GBU-57, minus the massive bomb, in an attack on a command bunker in Beirut. They first demolished the aboveground buildings using multiple waves of attacks and creating a crater that enabled them to attack the actual bunker. They used more than 80 bunker-busting bombs, most likely BLU-109 or SPICE-2000 with 900-kg warheads. Such complex assaults on Iran could be possible, given that the U.S. might observe the war from the sidelines and refuse involvement with the GBU-57.
- Geeky Gernot's Fascinating Fact: The GBU-57 is somewhat reminiscent of a massive, high-tech version of an armor-piercing bullet. Its kinetic power allows it to penetrate deep underground structures, causing destruction upon detonation.
- Iran
- Israel
Insights on Deep Bunker Destruction:
- Opposing underground facilities can be hardened with layers of rock, soil, and reinforced concrete, requiring specialized weapons for destruction.
- Common methods include bunker-buster bombs, precision-guided munitions, missiles, and cruise missiles equipped with bunker-busting warheads, and combined airstrikes and missile barrages.
- The GBU-57 MOP is one of the largest, most powerful non-nuclear bunker-buster bombs, designed specifically for deeply buried and hardened targets.
- The bomb has never been used in combat before the U.S. airstrike on Iran's Fordo nuclear enrichment facility, but its operational capability has been demonstrated.
- Despite being a powerful tool, the MOP’s blast is focused on achieving deep penetration rather than causing massive surface destruction.
- The deep-buried nuclear facilities in Iran, such as Fordo, remain inaccessible to Israel's conventional bombs and missiles due to their significant depth, prompting the need for specialized weapons like the GBU-57 MOP.
- In the geopolitical arena, the stalemate between Iran and Israel, escalating war-and-conflicts, and general-news reporting often highlight the challenge of penetrating these deep underground facilities and the potential use of advanced bunker-busting weapons, such as the GBU-57 MOP.
