Introduction: Weapons Technology

Violence and conflict have been a feature of human life throughout history. Starting with simple weapons, people have developed ever more advanced methods to kill one another. Technology has dominated warfare since the early 1900s, and an astounding 190 million people may have been killed during the 25 biggest conflicts of the 20th century.

Today guided weapons, like "smart" bombs dropped by stealth bombers, coupled with space-based sensors and precision satellite navigation, provide decisive advantages in conventional warfare. In this high-spending game, less capable opponents are soon reduced to guerrilla tactics, and human cost of war remains high.

The US has embraced Full Spectrum Dominance, the belief that superior technology in all fields guarantees victory, though critics disagree. This has led to ever more sophisticated and expensive aircraft and a proliferation of unmanned systems, including robot aircraft to attack targets. Future plans may include swarms of flying robots, while an existing desert race for driverless vehicles may pave the way for autonomous supply vehicles.

The infantry of the future may be kitted out with powered exoskeletons and accompanied by robotic pack mules.

Advanced technology

The future battlefield might also extend to space, with orbiting arsenals and high-altitude aero-spaceplanes, though robot spacecraft capable of intercepting satellites may be intended more to protect the military's investment in Global Positioning Systems and other orbital assets.

As opponents who lack high technology are reduced to hiding in the face of ever-increasing firepower, new weapons are being developed to attack the deepest bunkers, including "supercavitating" warheads and burrowing bombs.

One of the most ambitious schemes is to build a shield to defend the US from ballistic missiles. This would rely on a combination of airborne lasers and missiles, but the laser programme has proved more challenging than expected, as has hitting a missile with another missile. But lasers have succeeded in shooting down tactical rockets and even artillery shells.

Neutrino beams that could travel through the Earth and zap nuclear missiles on the other side of the planet have even been envisioned.

However, many critics doubt whether a missile defence scheme could work, and suggest that intercepted warheads might fall on Europe, Canada or middle America.

Less lethal

The debate between weapons developers and their critics is also intense in the field of non-lethal (or less-lethal) weapons, intended to incapacitate without killing. Controversial Taser guns - delivering an electric shock via wires - are widely used by police and military. New wireless versions are under development, which can "sweep" crowds with electrical energy, as well as electroshock projectiles and other devices.

The US military have developed the Active Denial System, or "people zapper", which uses a microwave beam to inflict pain without damage, as well as the Pulsed Energy Projectile - a non-lethal laser causing incapacitating pain. But there are fears that such weapons could be abused.

Lasers have also been proposed as dazzle weapons, such as the veiling glare laser, the portable PHASR and the helicopter-mounted ACCM. In all cases there have been concerns over safety and eye damage.

Non-lethal chemical weapons include "calmatives" such as the anaesthetic derivative disastrously used in a Moscow theatre siege. US chemical research has included such unlikely ideas as a weapon to disrupt enemy troops by turning them temporarily homosexual. There are also serious legal questions about chemical weapons treaties.

While some non-lethals have spread beyond the military - such as the acoustic LRAD, used to repel pirates - there are continuing concerns too little is known about their effects.

Conflict aftermath

Although technologists may strive for "surgical" strikes and quick victories, war leaves many problems behind for people, agriculture, the environment - and even the preservation of history. The WHO estimates that 731,000 people were killed by war and violence worldwide in 2002 alone.

Landmines are a particular issue, as there is no safe, quick or cheap method to deal with the millions of devices left fromprevious conflicts. Technological solutions to de-mining include special arrow projectiles, lasers and NMR scanners. There are moves to get around the Ottawa convention banning landmines, by replacing them with non-lethal devices or weapons that can tell troops from civilians.

Unexploded weapons are lingering threats. These days they are more likely to be cluster bombs, but an incredibly dangerous cargo ship of unexploded bombs is sitting in a sandbank in the River Thames estuary, UK.

Another war hangover is radioactive depleted uranium. This is used in anti-tank weapons and remains on the battlefield years later. Although the risks are still uncertain, there are moves to replace it with tungsten.

The mental after-effects of war are becoming more fully appreciated, with a growing understanding of post traumatic stress disorder. Researchers are also finding out more about debilitating effects of sleep deprivation on soldiers and other factors which contribute to "friendly fire" incidents.