What is MIRACL?

The provocatively-named MIRACL is the United States Navy's only known successful directed energy weapon. It stands for "Mid-Infrared Advanced Chemical Laser" and was originally built to take down anti-ship cruise missiles, but its use has since been extended to test aspects of anti-ballistic missile and anti-satellite laser weapons. Built by TRW Incorporated, the defense wing of which was acquired by Northrop Grumman in 2002, MIRACL is a spin-off of Ronald Reagan's famous Star Wars project, notorious for consuming billions of dollars with little useful hardware in return. MIRACL has not yet been mass produced or installed on ships, but its permanent home is the High Energy Laser Systems Test Facility (HELSTF), at White Sands Missile Range, New Mexico.

MIRACL is the first megawatt-class, continuous wave chemical laser in the world. MIRACL's method of operation can be compared to a rocket engine, where the fuel, ethylene (C₂H₄) is burned with an oxidizer, nitrogen trifluoride, (NF₃). In the ensuing energetic reaction, free fluorine atoms are one of the combustion products. Downstream from the combustion reaction, helium and deutrium are combined with the fluorine.

Deutrium combines with the fluorine to create deutrium flouride, while the helium modulates the reaction. Detrium flouride is the lasing medium, magnifying light intensely as it bounces back and forth inside the laser cavity. A semi-slivered mirror released the resulting optical energy into a focused beam with more than a megawatt capacity, equivalent to 100,000 typical light bulbs, but focused into a beam only 14 cm (~5 in.) in diameter.

Tests of MIRACL have shown it can indeed take down cruise missiles. In 1997, amid much controversy, the laser was fired at an old Navy satellite to measure the effects of ground-based laser weapons on satellite electronics. The test was successful. The controversy stemmed from concerns that the laser test was violating treaties against the use of weapons in outer space. Anti-satellite attacks could be foundational to any war in the future, in which all the big players would depend on satellite-based reconnaissance and navigation for all the functions of war.

MIRACL is definitely the start of something bigger - both the Army and Navy have shown great interest in directed energy weapons and consider them the future of warfare. Because they expend no ammo, they are cheaper to use than conventional guns. The fact that photons travel at the speed of light is also attractive.