The Economist looks at the long-anticipated introduction of energy weapons. They’re still a long way from matching the fictional capabilities of phasers, blasters, disruptors, or photon torpedoes:
In the late 1970s and early 1980s the idea was revived when American strategists began thinking in earnest about the technologies they would need to shoot down nuclear-armed ballistic missiles. Among the more fanciful ideas taken up by Ronald Reagan’s Strategic Defence Initiative (more commonly known as Star Wars) was the X-ray laser, which aimed to harness the energy of an atomic explosion to generate powerful laser beams. The hassle of having to explode a nuclear bomb every time a beam was needed meant the idea never went anywhere, though it did spur research into high-powered chemical lasers and the sophisticated optics needed to aim and control them.
The main appeal of using an energy beam to shoot things is that it travels at the speed of light, which means, in practice, that it will hit whatever it is aimed at. Trying to shoot down an incoming missile or warhead with a physical projectile, by contrast, is much more difficult. The guidance challenges of trying to “hit a bullet with a bullet” are enormous and are only gradually being solved using complex radars and missiles equipped with expensive sensors. A second attraction of lasers and other energy weapons is that in most cases they cannot run out of ammunition, and can keep firing for as long as they are plugged into a power source. The initial costs may be quite high, but each shot may then cost only a few dollars, compared with a price-tag of $3m or more for the latest missiles used to shoot down aircraft or other missiles.
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The big trend now is to try to scale up three other sorts of laser that are far more compact than chemical lasers and can fire away merrily as long as they have power and don’t get too hot. The first sort is the fibre laser, in which the beam is generated within an optical fibre. Because this is already used in industry for welding and cutting, prices are falling, power output is increasing and reliability has been steadily improving. Industrial lasers can be turned into weapons pretty easily, simply by strapping them to a weapons mount.
But they are not very powerful. The Tactical Laser System being developed for the American navy by BAE Systems, a British firm, has an output of just 10kW, enough to run a few household kettles. Even so, it might be useful for frightening off (or burning holes in) small boats that look threatening but wouldn’t warrant a hail of machinegun fire. A slightly bigger version puts out about 33kW of power and fits neatly on existing turrets that house the rotary cannons used to shoot down incoming anti-ship missiles. It could blind optical or heat-seeking sensors on enemy missiles, or puncture small boats.
