The Mark 84 or BLU-117 is a 2000 lb American general purpose aircraft bomb. It is the largest of the Mark 80 series of weapons. Entering service during the Vietnam War, it became a commonly used US heavy unguided bomb. At the time, it was the third largest bomb by weight in the US inventory behind the 15000 lb BLU-82 "Daisy Cutter" and the 3000 lb M118 "demolition" bomb. It is currently sixth in size due to the addition of the 5,000 lb GBU-28 in 1991, the 22600 lb GBU-43/B Massive Ordnance Air Blast bomb (MOAB) in 2003, and the 30000 lb Massive Ordnance Penetrator.

Development and use

The Mark 84 has a nominal weight of 2000 lb, but its actual weight varies depending on its fin, fuze options, and retardation configuration, from 1972 to 2083 lb. It is a streamlined steel casing filled with 945 lb of tritonal high explosive. The Mark 84 can form a crater 50 ft wide and 36 ft deep. It can penetrate up to 15 in of metal or 11 ft of concrete, depending on the height from which it is dropped, and causes lethal fragmentation to a radius of 400 ft. Many Mark 84s have been retrofitted with stabilizing and retarding devices to provide precision guidance capabilities. They serve as the warhead of a variety of precision-guided munitions, including the GBU-10/GBU-24/GBU-27 Paveway laser-guided bombs, GBU-15 electro-optical bomb, GBU-31 JDAM and Quickstrike sea mines. The HGK is a Turkish guidance kit used to convert 2000-lb Mark 84 bombs into GPS/INS guided smart bombs. According to a test report conducted by the United States Navy's Weapon System Explosives Safety Review Board (WSESRB) established in the wake of the 1967 USS Forrestal fire, the cooking off time for a Mk 84 is about 8 minutes 40 seconds.

Deployment in wars

MK 84 were used by U.S. forces in the Vietnam War, Operation Desert Storm, Iraq War and Afghanistan War and bombing of Yugoslavia in 1999, and by Israel in the 2014 Gaza War and 2023-2024 Gaza War. According to a forensic investigation by Human Rights Watch, MK 84 bombs were also in the Saudi-led intervention in the Yemeni civil war. In 2023 and 2024, the United States transferred over 14,000 Mark 84 bombs to Israel. They have been used extensively in the Gaza Strip during the Israel–Hamas War. At least one of the bombs was used in the 13 July 2024 al-Mawasi attack that killed Hamas commander Rafa Salama and 90+ civilians. According to the US Senator Mark Kelly, Israel used a bomb of this type in the assassination of Hassan Nasrallah, leader of Hezbollah, in Lebanon on September 27, 2024.