Pentagon deploys massive GBU‑57 bombs in Yemen offensive
According to American media, the Pentagon has decided to deploy the world's heaviest bombs. The GBU-57 MOP bombs were reportedly used in Yemen during attacks on the Houthis, conducted with the strategic, stealthy B-2 Spirit bombers.
The use of the world's heaviest bombs by the U.S. Air Force was reported by The Aviationist, citing Fox News journalist Jennifer Griffin. GBU-57 MOP bombs were said to have been dropped by B-2 Spirit aircraft.
To attack targets in the Middle East, the American bombers were relocated from U.S. territory to the Diego Garcia base in the Indian Ocean.
When the Pentagon released a video in 2019 showing the drop of the GBU-57 bomb, commentators considered it a threat towards Iran. It is unclear if the use of this weapon in 2025 was due to operational necessity or, like six years ago, was primarily a demonstration of strength and the ability to destroy not only targets in Yemen but also deep underground Iranian weapons depots.
The world's heaviest bomb
The GBU-57 MOP (Massive Ordnance Penetrator) is the heaviest known contemporary aerial bomb, with a length of about 6 metres and a weight exceeding 13 metric tonnes, with roughly 3 tonnes of explosive charge.
The GBU-57 was developed for attacking heavily fortified underground targets that could not be destroyed using other conventional weapons designed for similar purposes, such as the GBU-28 or GBU-37 bombs.
The GBU-57 bomb was developed following experiences with bombing Iraqi bunkers, which proved more difficult to destroy than previously assumed. Compared to its weight, the GBU-57 carries a relatively small amount of explosive material.
This is because the bomb has a specially reinforced, heavy body made of resistant steel, allowing for very deep penetration into the ground or breaking through the roof of an underground bunker. The bomb can target areas protected by an estimated 40 metres of solid rock or 60 metres of reinforced concrete.
Due to its size, the GBU-57 bomb can only be carried by large aircraft, such as the B-2 Spirit, B-52 Stratofortress, and – probably – the B-1B Lancer. In the future, the B-21 Raider will also join them.
