BLU-82/B 15,000-lb Bomb
Project Commando Vault
The BLU-82/B (Bomb Live Unit-82) was a 15,000 pound bomb originally designed to clear helicopter landing zones in Vietnam. The warhead contained 12,600 pounds of GSX (Gelled Slurry Explosive) filler called DBA-22M. The bomb is detonated a few feet above ground level by a 38-inch fuze extender, optimized to clear vegetation while creating no crater. Nicknamed "Big Blue [BLU] 82," the weapon is frequently and incorrectly referred to as "Daisy Cutter," a term which more properly applies to the fuze assembly for above-ground bursts.
GSX is prepared by forming a slurry of combinations of different ingredients. After the material has gelled, it is detonated by a high explosive booster. Slurry explosives are used in mining where formations to be fractured are wet, very dense, or strong. Slurries are very inexpensive compared with conventional military explosives and much easier to load into large casings. With slurry, filling a bomb is merely a matter of pouring the material into the casing. The slurry can be stored in non-explosive component form and turned into field-manufactured explosive as it is needed. Slurries, sometimes called water gels, contain ammonium nitrate partly in aqueous solution. Adding powdered aluminum as a sensitizer to slurries greatly increases the heat of explosion or the energy release. Aluminized slurries have been used in extremely hard rock with excellent results.
Melvin A. Cook's life was intimately connected with the history of explosives. He was a scientist, inventor, teacher, businessman, theorist, consultant, expert witness, entrepreneur, and author. Cook's personal involvement in both the theoretical and practical aspects of the field of explosives spanned more than 50 years. Cook's greatest commercial explosives invention was formulated in December 1956, when he created a new blasting agent using an unusual mixture of ammonium nitrate, aluminum powder, and water. The safety and efficiency of this new explosive was immediately apparent, and the use of water was revolutionary. Tests that followed resulted in the development of a new field of explosives: slurry explosives. This invention converted the commercial explosives industry from "dangerous dynamite" to "safe slurry" and dry blasting agents (ANFO). In 1972, Cook helped developed the BLU-82/B, the largest and most powerful bomb to use aluminized slurry. Cook, a professor of metallurgy at the University of Utah, was a businessman and author of works on explosives. He also published works on creationism, particularly on the relationship between science and Mormonism. Cook died in 2000.
Too large to be carried by conventional fighter or attack aircraft and not suitable for use from conventional high-altitude bombers, the delivery system for the BLU-82/B was the C-130 aircraft, primarily special operations MC-130s. This BLU-82/C-130 system depended upon the accurate positioning of the aircraft by either a fixed ground radar or onboard navigation equipment. The ground radar controller or aircrew navigator as applicable, was responsible for positioning the aircraft prior to final countdown and release. Primary aircrew considerations include accurate ballistic and wind computations provided by the navigator, and precision instrument flying with strict adherence to controller instructions. The minimum altitude for release due to blast effects of the weapon was 6,000 feet above ground level.
The DBA-22M explosive, supplied by IRECO Chemicals of Salt Lake City, Utah used in the BLU-82/B had been part of development at Sandia Laboratories. A requirement had been developed for a conventional high explosive that could be used in a test device capable of producing a simulated nuclear cloud for the exercise of RB-57 sampler aircraft under Project Cloudmaker. The Project Cloudmaker device, which was not built, was to have weighed 45,000 pounds.
Instead, the filler was used to develop the BLU-82/B as part of Project Commando Vault, which sought to develop systems for the rapid clearing of helicopter landing zones in Vietnam. As part of the requirements outlined in SEAOR 168, a weapon was required to clear a 5-helicopter zone, the number of helicopters determined to be optimal reportedly "snatched out of thin air at random, rather than being the product of meticulous estimates and careful calculations." In early December 1968, the Air Force had requested Sandia Laboratories, through the Albuquerque Operations Office of the Atomic Energy Commission, to design and develop a possible follow-on bomb to the 10,000 pound M121, which was being used in Commando Vault operations. The new design would weigh 15,000 pounds and be filled with DBA-22M. The resulting design and development program lasted approximately one year, winding up in the autumn of 1969.
With the development program completed, the Air Force requested the Albuquerque Operations Office of the AEC to undertake, through Sandia Laboratories, the fabrication of 225 emergency-capability 15,000-lb, BLU-82/B bombs. Simultaneously, program management was transferred from the Special Applications Branch at Kirkland Air Force Base to the Armament Development and Test Center at Eglin Air Force Base.
Following tests of prototype weapons as part of Project Cloudmaker, the first live, full-scale test drop of a CD-1 (later to be redesiganted BLU-82/B) at the Tonopah Test Range was conducted on 1 April 1969, the rigging of the bomb and its cradle to the Air Force aerial delivery platform having been performed at El Centro Naval Air Facility. The rigged bomb was loaded on a C-130 aircraft and the drop staged out of Hill Air Force Base. The bomb impacted on one of the large dry lake bed targets at the Tonopah Range. Informed of this test, Seventh Air Force recommended that any decision on whether or not to produce more M121s be delayed until the results of the Nevada desert drop could be evaluated.
The results of the Nevada tests showed that the larger weapon had significantly greater blast effect and peak overpressure than the M121, but unable to get the new weapons quickly into the field for comparative field tests, M121s continued to be used for Project Commando Vault. The long-awaited opportunity to compare the effects of the weapons came in the spring of 1969, when the first of the experimental CD-1s arrived in SEA. The initial CD-1s were virtually handmade, but functioned perfectly. On 11 May 1969, 2 CD-1s and 2 Ml21s were dropped, to permit a comparison of the 2 weapons. Even though the CD-1 did not satisfy the requirements of SEAOR 168, the results were impressive enough to prompt the Commander, Seventh Air Force, to press for use of the CD-1 in lieu of revived production of the M121. Of additional importance in this decision was the fact that the production version of the CD-1 could be in the theater by early 1970, while the lead time for resuming production of the M121 was placed at 15 months.
In the end, the remaining stock of M121s were used, even after the first batch of production BLU-82/Bs had arrived in February 1970. The first drop of the production models took place on 23 March 1970. On 8 August 1970, the last M121, leaving only BLU-82/Bs to perform the Commando Vault function. During operations, although the cargo compartment of the C-130 was large enough for 2 BLU-82/B bombs, only one was carried, inasmuch as center of gravity characteristics of the Hercules would render a safe landing impossible, should circumstances require a return to base with one bomb of a 2-bomb load still aboard.
The first BLU-82/B was dropped in support of operations in Cambodia in the southeastern portion of the country, not far from the border with South Vietnam, on 1 May 1970. Before the US forces pulled out of Cambodia, 15 more BLU-82/Bs were dropped.
After the end of the the conflict in Southeast Asia, the US Air Force retained the remaining BLU-82/Bs. Eleven BLU-82/Bs were subsequently dropped during Desert Storm, all from Special Operations MC-130s from the 8th Special Operations Squadron. The initial drops were intended to test the ability of the bomb to clear mines. No reliable bomb damage assessment was subsequently gathered on mine clearing effectiveness. Later, bombs were dropped as much for their psychological effect as for their destructive power.
As of 13 December 2001, the US had dropped at least 4 BLU-82/B bombs in Afghanistan, mainly on tunnels reportedly holding top al Qaeda leaders.
Airmen from the 711th Special Operations Squadron dropped the last operational BLU-82/B from an MC-130E Combat Talon I on 15 July 2008 at the Utah Test and Training Range. Wing officials said they believde there were no plans, at that time, to produce BLU-82/Bs in the future. The only remaining inactive bombs were used for loadmaster training and for static displays in museums.
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