American B52 bombers
The 30,000-pound Massive Ordnance Penetrator (MOP) is the largest bomb in the U.S. arsenal, and its new design is tailored specifically for striking Iran's Fordow nuclear enrichment complex.
Adam Entous and Julian Barnes at The Wall Street Journal (WSJ) report that not only has the MOP been refined for an Iranian strike, but it's also being used to assure Israel the U.S. can keep Tehran from acquiring a nuclear bomb.
Several times in recent weeks, American officials, seeking to demonstrate U.S. capabilities, showed Israeli military and civilian leaders secret Air Force video of an earlier version of the bomb hitting its target in high-altitude testing, and explained what had been done to improve it, according to diplomats who were present, reports Business Insider.
In the video, the weapon can be seen penetrating the ground within inches of its target, followed by a large underground detonation, according to people who have seen the footage.
The upgrades include " adjusted fuses to maximize its burrowing power, upgraded guidance systems to improve its precision, and high-tech equipment intended to allow it to evade Iranian air defenses … [as well as] capabilities designed to counter Iran's air defenses and keep the bomb on target if the Iranians try to knock it off course."
Iran's Fordow complex, buried about 300 feet beneath a mountain near the city of Qom , is believed to contain more than 2,700 centrifuges enriching uranium.
Initial modification of the MOP was announced in January when the Pentagon’s director of operational testing Michael Gilmore confirmed that tests conducted with the heavy GBU-57 MOP GPS-guided bomb, thought able to penetrate 200 feet of concrete before exploding, had demonstrated it was able to hit and destroy deeply buried targets.
The enhanced MOP features tail-fin modifications to fix bugs identified in testings as well as a second fuse to destroy hardened underground targets.