Peace Through Light - the Airborne Laser Lab Program

te c h o p s D irected Energy Weapons (DEW) have been a recurring theme in science fiction literature and cinema ever since H.G. Wells published the ‘War of the Worlds’ in 1898. The idea of a ‘death ray’ that can instantly destroy or burn a target at a distance retains its allure to this very day. More than a century after Wells contrived his ‘heat ray’ the technology is maturing to the point of becoming deployable soon. High Energy Laser weapons have been evolving since the 1960s, a path punctuated by a series of important scientific breakthroughs and engineering milestones. The popular view of a HEL, seen as constructing a huge laser and pointing it at a target with the intention of vapourising it, bears only vague similarity to a real HEL weapon. There are genuine technological and operational challenges involved in creating truly useful and effective weapons. Kinetic or projectile weapons such as guns, missiles and bombs destroy targets by kinetic effects, including overpressure, projectile, shrapnel and spalling damage, and incendiary effects. The result is structural damage and fire, which can and often will cause fatal damage to a target. A kinetic weapon thus uses stored chemical energy in propellants and warhead explosives, where used, and delivers this energy to a target by means of a projectile of some kind. Whether the projectile weapon is a trebuchet tossing a large rock over 300 yards, or a multimode seeker-equipped long range air-to-air missile hitting an aircraft from 200 nautical miles away, the underpinning principle is much the same, only the implementation is different. At the most fundamental level, Directed Energy Weapons share the concept of delivering a large amount of stored energy from the weapon to the target, to produce structural and incendiary damage effects. The fundamental difference is that a Directed Energy Weapon delivers its effect at the speed of light, rather than supersonic or subsonic speeds typical of projectile weapons. Two of the most fundamental problems seen with projectile weapons – getting the projectile to successfully travel a useful distance and hit the target, and then produce useful damage effects – are problems shared by Directed Energy Weapons. Having a powerful laser or microwave emitter maketh not a Directed Energy Weapon system alone. Most contemporary literature lumps together a broad mix of weapons technologies in the Directed Energy Weapon category, including High Energy Laser (HEL) weapons, High Power Microwave (HPM) weapons, particle beam weapons and Laser Induced Plasma Channel (LIPC) weapons. The first two of these four classes of weapon are genuine Directed Energy Weapons. Particle beam weapons are best described as a form of projectile weapon, using atomic or subatomic particles as projectiles, accelerated to relativistic speeds. The LIPC is a hybrid, which uses a laser to ionise a path of molecules to the target, via which an electric charge can be delivered to cause damage. Of these four categories, HELs have the greatest potential in the near term to produce significant effect. HPM technology has similar potential but has not been funded as generously and lags well behind lasers. LIPC has significant potential especially as a non-lethal weapon. Particle beam weapons at this time are apt to remain in the science fiction domain, as the weight and cost as yet do not justify the achievable military effect.