AGM-114N Metal Augmented Charge (MAC) Thermobaric Hellfire
The improved, Metal Augmented Charge (MAC) thermobaric warhead for the AGM-114 Hellfire missile dramatically increased effectiveness against enclosed targets. The chemical mix selected for the AGM-114N Thermobaric Hellfire warhead fill is substantially more effective in attacks against enclosed structures than the current Hellfire blast and fragment variants. The thermobaric Hellfire missile can take out the first floor of a building without damaging the floors above, and is capable of reaching around corners, striking enemy forces that hide in caves or bunkers and hardened multi-room complexes. Coalition military planners use a sophisticated computer model to determine the precise direction, the angle of attack, and the type of weapon needed to destroy desired targets, while sparing nearby civilian facilities.
The effects of the Hellfire MAC warhead are formidable. Unlike conventional warheads, which have a sharp pressure spike that decays rapidly, the MAC has a sustained pressure wave. That pressure propagates throughout a structure to extend the lethal effects of the warhead detonation.
The DoD Combating Terrorism Technology Task Force (CTTTF) has been structured to continually strive to derive new capabilities from S&T programs, as well as attempt to anticipate future capabilities needs. The original CTTTF model was conceived within a week of the attacks of September 11, 2001, when the Department established CTTTF. In Phase II, the CTTTF reacted to a broad set of operational issues that emerged leading up to and including support for Operation Iraqi Freedom. Technologies were accelerated to fielding for several specialized, unique weapons which focused on specific, anticipated threats.
Notable among the CTTTF efforts was the AGM-114N Thermobaric Hellfire which built upon previous efforts supported by the CTTTF in development of thermobaric weapons which were employed in Afghanistan in Operation Enduring Freedom. DTRA worked in coordination with the Army and Navy, on the AGM-114N Hellfire development effort. Several candidate thermobaric warhead fills were tested and assessed during final development. In FY 2003 DTRA delivered 65 Hellfire AGM-114N missiles with improved warheads for increased blast lethality for US Marine Corps Military Operations in Urban Terrain (MOUT).
In 2002, the DTRA tasked NAVAIR to develop a new Hellfire warhead. The requirements had been established by the Marine Corps Department of Aviation (APW-72) to make the Hellfire more suitable for Military Operations in Urban Terrain. The number one requirement was that the new warhead increase the probability of personnel lethality or incapacitation. Additionally, the warhead had to maintain lethality equivalent to the AGM-114M against the remainder of the Marine Corps target set, possess the same flight performance and accuracy as the 114M, keep the same interfaces with the Hellfire missile system and be compatible with the Hellfire logistical cycle.
The MAC technology used in the new warhead has its roots at China Lake where, as early as the 1960s, Navy scientists were conducting basic research into fuel-air explosives (FAEs). China Lake scientists and engineers subsequently developed these concepts into tactical weapons: surface-launched FAE (SLU-FAE) and the CBU-55/72 FAE family.
In the 1990s, the Energetics Materials and Ordnance Components Branch worked with China Lake and others to develop nonliquid FAEs containing aluminum particles. The goal was a solid FAE with a greater impulse (pressure over time) than conventional explosives. They were successful in developing a class of explosives that demonstrated greater impulse than non-augmented explosives. The work received a classified US Patent and was the basis for the MAC warhead.
The new warhead contains a fluorinated aluminum powder layered between the warhead casing and the PBXN-112 explosive fill. When the PBXN-112 detonates, the aluminum mixture is dispersed and rapidly burns. The resultant sustained high pressure is extremely effective against enemy personnel and structures.
NAVAIR managed the MAC warhead project through its first two phases. Six warhead-fill candidates were considered in phase 1, and the top three were selected to proceed into phase 2, where the down-select process was completed. The warhead design was finalized in September 2002, and the PBXN-112/MAC warhead proceeded into phase 3, qualification testing.
It went from development to deployment in less than one year. The demonstration program developed weapons in approximately one year with an initial delivery of approximately 60 residual assets. An urgent request was received from the Marine Corps to begin immediate fabrication of 65 warheads. Five of these were to be used for a Quick Reaction Assessment (QRA). The balance would be destined for field use by Marine Corps operational units.
The 65 warheads were built and integrated into the armament sections at NAVAIR WD. The sections were then shipped to Redstone Technical Test Center, Ala., where Army personnel used them to replace the armament sections of 65 AGM-114Ks. The QRA was conducted in January 2003. It involved tests against a bunker and cave on China Lake's Land Range and against a multi-room structure at White Sands Missile Range. COMOPTEVFOR directed the QRA, and VX-9 provided the helicopters and crews who did the shooting. All tests were completed successfully, verifying the performance of the MAC warhead.
Multiple missiles were deployed and successfully employed in the opening of Operation Iraqi Freedom. Since that time, the Department has invested additional funds in the AM-114N and will deliver over 100 units to USMC and SOCOM by June 2005. The AGM-114N transitioned to production with a significant increase in fielded units planned over the following two years.
It was revealed in mid-May 2003, by US Secretary of Defense Donald Rumsfeld that US forces had for the first time used a new thermobaric variant of the Hellfire missile during the conflict in Iraq. No additional details were revealed as to how and where the weapon had been used. DefSec Rumsfeld cited this weapon as a case of high-speed research and development executed to meet a critical battlefield need, with the project going from development to deployment in less than one year.
Navy JAG (Code 10) JAO commented in late 2002 on a legal review of the Hellfire PBXN-112/MAC warhead missile. The missile provides increased effectiveness against targets typically encountered in Military Operations in Urban Terrain (MOUT) by creating increased blast over-pressure and impulse to defeat multi-room structures. The missile is also effective against caves, light armor, trucks, radar vans, buildings, light bunkers, command and control sites, patrol boats, light ships, the superstructure of heavy ships, deck mounted weapons systems and troop concentrations. Based on JAO comments, Navy JAG revised the review to include discussion of the BLU-118 and the thermobaric SMAW, two weapons systems already in the inventory which also rely on over-pressure as the killing mechanism.
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