The U.S. Department of Defense wants to test a directed energy weapon in space, one that it hopes will someday destroy ballistic missiles moments after launch. The weapon, a so-called neutral particle beam, would be boosted into space and tested from orbit in 2023.
Neutral particle beams don’t get as much attention as lasers but are attractive in their own right. The weapons work by accelerating particles without an electric charge—particularly neutrons—to speeds close to the speed of light and directing them against a target. The neutrons knock protons out of the nuclei of other particles they encounter, generating heat on the target object.
Particle beams are effectively the “heat rays” or even “death rays” of science fiction. Unlike lasers, which burn the surface of a target, particle beams penetrate beyond the surface to affect its interior. This makes particle beams immune to measures that can deflect lasers, like brightly polished, mirror-like surfaces. A sufficiently powerful beam could generate enough heat to burn a target, igniting its fuel supply, melting it and rendering it aerodynamically unstable, or frying a missile’s onboard electronics.
A neutral particle beam requires an accelerator to produce the atomic or subatomic particles that make up the beam. The accelerator must produce a tremendous amount of particles in a very short amount of time, then release them in a focused beam. A weaponized neutral particle beam would also need a power supply, a power storage system, and staging system to feed energy to the accelerator. Finally, it would require an aiming system and either onboard sensors or communications links allowing it to take targeting cues from other space or air-based sensors or a centralized battle management system.