The Massive Ordnance Penetrator Bomb Israel Wants to Destroy Iran’s Fordo Nuclear Facility

Why is the only bomb that could destroy the nuclear bunker from Iran – under 300 feet of rock

By Deni Ellis Béchard Edited by Dean Visser

The challenge seems unreal: how to explode a hole through a mountain of concrete and granite, then explode what is hidden below and Horbar; All without crossing the nuclear line? The solution is a bomb that weighs 30,000 pounds, almost as much as a bus in the city, but which is compressed in a cylinder approximately 20 feet long and 2.5 feet thick. Since the Israeli-Iranian conflict broke out last week, many speculations have focused on this weapon: GBU-57 / B, the most powerful non-nuclear bomb which is capable of destroying targets deep below the earth. The question that many are asking is whether the United States – the only country with the bomb – will provide it to Israel.

To understand what GBU-57 / B is and why Israel might want the weapon, it is important to understand the alleged target: Fordo, the most advanced nuclear enrichment installation in Iran, which is 18 miles northeast of the central city of Qom. According to an Institute for Science and International Security report, the site has the capacity to produce enough uranium highly enriched to make a nuclear warhead in the space of a few days. It is also deeply installed under a mountain, less than 260 to 300 feet of rock reinforced with concrete and surrounded by a ring of air defense batteries. After Israel bombed the Iraqi nuclear reactor in 1981 and Syria in 2007, Iran decided to spread its nuclear program on several sites, with its crucial elements hidden so deep under the ground that even the bunker busters of 5000 pounds from Israel could not reach them. The intelligence reports suggest that Iran began construction in 2002, while Iran said that the work had started in 2007. Tehran recognized the existence of the site until September 2009.

The first three letters of GBU-57 / B represent “the guided bomb unit” (a precision bomb that can be at home on its target), and it is the 57th design of the series of these bombs. The second B refers to the iteration of the bomb (designations such as A / B, B / B, C / B, etc. are used for each adjustment made by military engineers). After Iraq’s invasion in 2003 in the United States, the engineers studied bunker strikes with smaller and older GBU models and found that they had not penetrated deep enough and had done limited damage. The soldiers required a more powerful weapon that would respect the “nuclear taboo”, an international consensus widely accepted on the fact that the use of nuclear weapons is morally odious and dangerous because it creates radioactive benefits, invites climbing and risks leading to allies and neutral states in diplomatic revolt. GBU -57 / B – also known as a massive ammunition penetrator (MOP) – was a solution. His Air Force information sheet summarizes him as “a system of weapons designed to accomplish a difficult and complicated mission to reach and destroy the weapons of mass destruction of our opponents located in well -protected facilities.”

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When it went from 50,000 feet, the cruise ceiling for the B-2 Spirit bomber, the GBU-57 / B uses sophisticated fins to guide it to its target. Although the exact impact speed is classified, it should exceed Mach 1 – the speed of the sound (767 MPH). This strike issues 800 to 900 megajoules (around 758,000 to 853,000 British thermal units) of kinetic energy – comparable to a Boeing 747-400 of 285 tonnes moving to 170 MPH or an Amtrak Acela train from 565 tonnes to 120 mph. With the bomb, however, all this energy is concentrated in a small area. According to a briefing of the 2012 Congress Research Service, GBU-57 / B was reported to dig 200 feet of concrete or rocky substratum with a density of 5,000 pounds per square inch (comparable to the force of the bridge terraces or parking garage slabs). Then his explosive load of 5,300 pounds explodes.

GBU-57 / B is designed to improve this ability to drill deeply below the surface. Its nose has a form of warhead, like that of a Gothic arch. As these arches are known to effectively distribute the weight, the nose of the bomb has no sharp corners that cause air drag. Then, during the impact, the rounded shape gradually distributes the initial crushing load through the steel housing of the bomb instead of concentrating it at a brittle point. This allows the case to remain intact when it flows into the earth. The case also has a high section density. In this context, the section density refers to the ratio of the mass of an object to the size of the face which first meets the surface of the object. A hammer hitting a board has a high section density because it concentrates its mass in a small area; A pillow does not do so. In the case of the bomb, a large part of the mass and the momentum is excited behind a small point. While the warhead nose minimizes the drag and the structural shock, the high section density concentrates the speed and the strength, allowing the bomb to strike deep into the stone.

About one fifth of the total weight of 5,342 pounds in the warhead is made up of two explosives: 4,590 pounds from AFX-757 plus 752 pbxn-114 pounds. The two create a larger explosion than the previous bombs while being sufficiently insensitive to survive the shock of the initial strike. The detonation itself is timed by a specialized fuse which can be programmed inside the Bombardier cockpit. The fuse “counts” the layers of rock or concrete, “hears” the hollow of a tunnel or a room, then draws a detonator in the smallest load PBXN-114 so that the main load explodes only after the bomb has pierced well inside the target. The released energy is about three to four tonnes of TNT. But because a large part of the 30,000 pounds of the bomb is made of hardened steel, a large part of its destructive effect comes from its kinetic punch, delivered at sound.

Although suspected of having nuclear weapons, Israel has so far respected nuclear taboo. To destroy Fordo without them, he would need both GBU-57 / B and a Bomber B-2 Spirit, the only plane designed to drop the bomb (he is able to release two, one of each bay). Otherwise, Israel could, in theory, only the periphery of Fordo – by destroying energy sources, by collapsing the entries or by sending saboteurs – while uranium continues to be enriched below. Fordo is so well protected that an editorial of the Royal United Services Institute declares that “even the GBU-57 / B would probably require multiple impacts at the same point of aim to have a good chance of entering the installation.” Despite the media claims that GBU-57 / B bombs were used to hit Houthi targets in Yemen, the US Air Force declares that these weapons have never been used in combat and that only a few dozen are stored. So far, the United States has refused to give Israel one of them-or the B-2 bomber necessary to drop and collapse a mountain.