Shooting down enemy air threats—whether they're ballistic missiles, cruise missiles, or aircraft—is a tactical problem that leaves little room for error. The targets move fast and must be verifiably, catastrophically, destroyed. An incoming missile hit and broken into pieces by an air defense missile can be as dangerous as one that lands intact. The Iraqi Scud missile that killed so many American troops at their Saudi base during the 1991 Gulf War is sad evidence of that risk—it had apparently been hit by a Patriot missile on its way down, but its warhead functioned on impact nonetheless. So the Navy's goal in improving the effectiveness of its air defense warheads is to enable them to inflict enough damage on an incoming missile to destroy it at a safe distance.
The Office of Naval Research is working toward this goal. ONR's Reactive Materials Enhanced Warhead Program seeks to demonstrate missile warheads that achieve visible catastrophic structural defeat of cruise missiles and manned aircraft. These new warheads enhance the kinetic energy of inert fragments with chemical energy released when reactive fragments hit the target. (Kinetic energy is simply the energy a body has by virtue of its motion—a linebacker brings down a running back through application of his kinetic energy; a thrown rock breaks a window by transferring its kinetic energy to the glass. Chemical energy is released in the form of heat and pressure, as when something burns rapidly—a gas main explosion or the detonation of stick of dynamite are good examples of the release of chemical energy.) The Reactive Materials Warhead combines both effects to increase the odds of destroying the target.
The new warhead uses a carefully designed chemical reaction to release heat and overpressure. These add to the destructive effect of the warhead fragments' kinetic energy as they strike the target. The fragments are composed of an advanced composite material made of powdered metal embedded in a plastic matrix that survives the explosive launch typical of warhead fragmentation. It promises potential lethality improvements of up to 500%.
This new reactive composite material was recently incorporated into a prototype warhead and used in a live-fire explosive static arena test against real and threat-representative targets. The demonstration showed that the new type of warhead has twice the lethal radius of its predecessors and improved structural target damage. The test results and engineering tool sets developed from this program are now being used to prepare the Reactive Material Enhanced Warhead for transition into Navy missile programs that include the STANDARD Missile, the High-speed Anti-Radiation Missile (HARM), the Advanced Medium Range Air-to-Air Missile (AMRAAM), the Sidewinder, and the Rolling Airframe Missile (RAM).