Top 10: weapons of the future

Top 10: Weapons of the future
12:07 04 September 2006 by Jeff Hecht
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We went from swords to machine guns and nuclear bombs, but what are the next weapons on the horizon? New Scientist rounds up ten of the most promising technologies.
1. Autonomous weapons

These are robotic vehicles, under development, that search and destroy enemy troops and equipment on the ground or in the air, without risk to friendly troops – theoretically.

How they work: Onboard computers interpret sensor data to identify and target hostile forces with built-in weapons. Robots may query human controllers at remote sites for the go-ahead to fire, and friendly forces may carry transponders that identify them as “friends”.

Limitations: Difficulty of quickly and reliably discriminating between hostile forces and neutral or friendly parties or objects, such as civilians, cows, trees, and tractors.

Systems that check with human controllers are vulnerable to communication failures. Malfunctioning robots could fire wildly at anything.
2. High-energy lasers

These are powerful energy beams that travel through air or space in straight lines. They travel at the speed of light and can strike over distances of thousands of kilometres.

How they work: Large mirrors focus powerful laser beams onto a small spot on the target. The heat produced burns through the surface of the target, disrupting flight, disabling warheads, or igniting fuels or explosives.

Limitations: It needs much more energy to do damage than bullets, which destroy targets with their momentum. Powerful lasers need fuel or electrical power and are also very bulky (the US Airborne Laser fills a Boeing 747). Travelling through air and turbulence can disperse the energy of the beam.
3. Space-based weapons

Space is the ultimate high ground, so weapons in orbit would have the ability to see and zap anything on the ground, in the air, or nearby in space.

How they work: The main mission of space-based weapons would be to defend against ballistic missiles fired at targets on Earth. Fleets of interceptors or battle stations would be stationed in orbit, poised to fire at any attacking missiles. The leading approach now is solid projectiles – such as tungsten rods – that would impact missiles. But laser battle stations are also under consideration.

Limitations: The technology is immature. Reaction times must be very fast. Interceptors must hit warheads to destroy them, which is difficult. Lasers also need chemical fuel or electrical power which is not readily available in space.
4. Hypersonic aircraft

Launched from a standard runway, a hypersonic aircraft could fly faster than Mach 5 to strike anywhere in the world within two hours. It would also have enough thrust to deliver a satellite to low-Earth orbit.

How they work: To get off the ground from a runway, a hypersonic plane would either hitch a ride on a conventional plane, or have its own conventional jet engine. That engine would carry the hypersonic craft to an altitude where air density and resistance are less. Here it would reach supersonic speeds and then shift to its scramjet engine. The scramjet scoops up air and mixes it with fuel so it burns as the mixture flows through the engine at supersonic speeds. This means scramjets can achieve some of the speed of a rocket without having to carry heavy oxidiser (to mix with fuel), as rockets do.

Limitations: The technology is immature, with many engineering issues unresolved.

Top 10: weapons of the future