Directed energy weapons: Will they ever be ready?

• Author: Robinson, Ariel

If Nikola Tesla had been deployed with the USS Ponce this past year, he would have been proud. A directed energy weapon--similar, in some ways, to his own 1934 invention "Teleforce"--was proved to be operationally effective on board a Navy ship for the first time.

The trials of the Navy's laser weapon system (LaWS) were hailed as a success. But despite promising test results and decades of research and development, it could be many more years before the military is ready to bring directed energy weapons into the mainstream.

The Defense Department defines directed energy as a "weapon or system that uses directed energy to incapacitate, damage or destroy enemy equipment, facilities and/or personnel." They require power levels of around 50 kilowatts or higher. To destroy anti-ship cruise missiles would require a beam of 500 kilowatts and demand megawatts of power.

There are two types: high-powered microwaves and high-energy lasers. High-powered microwaves emit electrically-powered pulses of microwave radiation at a wide angle, while high-energy lasers direct highly focused beams of lower-powered energy using one of two lasing mechanisms: chemical fuel or electric power.

Chemical lasers are the only systems that have produced megawatt-level outputs. However, they are fueled by a toxic cocktail of chemicals which require special handling, and have generally fallen out of favor in the United States. Another reason is that they rely on what is essentially an external/independent power source, and thus lack the key strategic value of directed energy weapons: a virtually unlimited magazine.

Solid state lasers are electrically powered, and they are separated into three types: Fiber solid-state lasers like LaWS, slab solid-state lasers, and free electron lasers. While they avoid the complicated logistics associated with chemical lasers, SSLs are generally not very efficient. In most cases, two-thirds to three-quarters of the energy required to operate them is dissipated as heat, which poses a challenge to most platforms' cooling capacities.

Reaching this point has taken nearly half a century, billions of dollars and a number of canceled programs. Observers have been skeptical of frequent claims that we are "just a few years away" from achieving an operationally effective and "manufacturable" directed energy weapon.

When asked what makes this time any different, most experts agree with David DeCroix, a congressional fellow on the House Committee on Homeland Security. In the early 1990s, while at Rockwell International, DeCroix worked on the Defense Department's airborne laser. One of the biggest differences between then and now, he said, is the access to computing power. "A desktop computer or small rack of high performance computing clusters makes the scientific and technical...