The U.S. military is bankrolling all kinds of projects to harness the power of directed energy, from laser-equipped aircraft that can shoot down ballistic missiles to smaller beam weapons mounted on Humvees that could zap mortars or artillery shells. The Navy is no exception: It wants a shipboard laser that is powerful enough to destroy anti-ship missiles.

Defense giant Boeing now says it has completed the preliminary design of one such weapon, the Free Electron Laser, or FEL. In a news release today, the company said it had presented its FEL design, which will operate by forcing a stream of high-energy electrons through a series of magnetic fields, creating a weapons-grade blast of laser light.

If it works, it would be the holy grail of military lasers. For starters, it would able to blast though the atmosphere without losing too much strength (see explanation here). And it would have an unlimited magazine: As long as the ship provided enough electrical power, it could keep on zapping.

Boeing isn’t the only company working on such a project. Last year, the Office of Naval Research awarded contracts to both Raytheon and Boeing for preliminary design work on FEL. As we reported, this laser would be capable of reaching up to 100 kilowatts. In theory, it would be a potential long-range replacement for the radar-guided Phalanx gun, the Navy’s current system for close-in defense from cruise missiles and other threats.