The GBU-43/B Massive Ordnance Air Blast bomb (MOAB) (colloquially known as the Mother Of All Bombs) is a large-yield conventional bomb developed for the United States military by Albert L. Weimorts Jr. At the time of development, it was touted as the most powerful non-nuclear weapon ever designed. The bomb was designed to be delivered by a C-130.
Since then, Russia has tested their "Father of All Bombs" and has claimed it to be four times more powerful than the MOAB, although the legitimacy of the Russian weapon's size and power has been called into question.
The MOAB is an Air Force Research Laboratory technology project that began in fiscal year 2002, as a descendant of the BLU-82 "Daisy cutter". It underwent a successful field test at Eglin Air Force Base, Florida on March 11, 2003 and another in mid-November. The U.S. Air Force Research Laboratory has said a larger version of the MOAB exists, weighing thirteen tons.
MOAB length is 30 feet, 1.75 inches (9.17 m), diameter is 40.5 inches (102.9 cm), weight is 22,600 lb. (9.5 tonnes), of which 18,700 lb. (8.4 tonnes) are high explosives. Blast radius is 450 feet (137.61m, 150 yards), though the massive shockwave created by the air burst is said to be able to destroy an area as large as nine city blocks. Due to its large size and weight, it must be dropped out of the back of a cargo aircraft, usually a C-130. It is guided by global positioning technology and uses a parachute to pull it out of the cargo door, so it can be dropped from a higher altitude and with higher accuracy than its predecessor, the BLU-82. It is the first U.S. weapon to use Russian-style lattice control surfaces (referred to as "Belotserkovskiy grid fins"), like those used on the R-400 Oka and Vympel R-77. It is only slightly smaller than the Grand Slam bomb of World War II.
The MOAB uses 18,700 pounds of H6 as its explosive filler. At 1.35 times the power of TNT, H6 is one of the more powerful explosives used by the U.S. military. H6 is an explosive combination of RDX (Cyclotrimethylene trinitramine), TNT, and aluminum. H6 is typically employed by the military for general purpose bombs, and is an explosive composition which is produced in Australia. H6 is a widely used main blast charge filling for underwater weapons such as mines, depth charges, torpedoes and mine disposal charges. HBX compositions (HBX-1, HBX-3, and H6) are aluminized (powdered aluminum) explosives mainly used as a replacement for the now obsolete explosive, known as torpex. HBX-3 and H6 have lower sensitivity to impact and much higher explosion test temperatures than torpex. The warhead is designated the BLU-120/B, Blast.
Although its effect has often been compared to that of a nuclear weapon, it is only about one thousandth the power of the atomic bomb used against Hiroshima: it is equivalent to around 11 tons of TNT, whereas the Hiroshima blast was equivalent to 13,000 tons of TNT and modern nuclear missiles are far more powerful than the atomic bomb used against Hiroshima. However, the MOAB bomb's yield is comparable to the smallest of nuclear devices, such as the M-388 Davy Crockett.
It was first tested with the explosive tritonal on March 11, 2003, on Range 70 located at Eglin Air Force Base in Florida. Aside from two test articles, the only known production is of 15 units at the McAlester Army Ammunition Plantin 2003 in support of Operation Iraqi Freedom. Since none of those are known to have been used as of early 2007, the U.S. inventory of GBU-43/B presumably remains at approximately 15.
The basic design bears some similarity to the BLU-82 Daisy cutter, which was used in the Vietnam War and in Afghanistan — mostly for clearing of heavily wooded areas in the former theater, and for attacking hardened targets in the latter. Unlike the Daisy Cutter, the MOAB is primarily intended for employment against deep and hardened targets. Further, the Daisy Cutter is unguided, parachute stabilized and requires a relatively low drop altitude, whereas the MOAB is a GPS guided free-fall weapon with significantly greater stand-off capability.
Pentagon officials had suggested their intention to use MOAB as an anti-personnel weapon, as part of the "shock and awe" strategy integral to the 2003 invasion of Iraq. The U.S. Air Force conducted tests where subjects were shown videos of the MOAB explosion. Except for the nuclear scientists shown the video as a control group, all other test groups identified the explosion (incorrectly) as a nuclear blast. This demonstrated the MOAB's potential to inspire psychological fear.
While the MOAB is primarily intended for deep and hardened targets, it can also be employed against soft to medium surface targets covering extended areas. However, multiple strikes with lower yield ordnance may be more effective and can be delivered by fighter/bombers such as the F-16 with greater stand-off capability than the C-130 and C-17. High altitude carpet-bombing with much smaller 2,000 or 1,000 pound bombs delivered via B-52s is also highly effective at covering large areas.