High-tech war: In the opening hours of the assault on Iraq, the US is likely to unleash a new and devastatingly effective breed of weapon against Saddam Hussein's forces. Launched in a cruise missile, it will fire a massive pulse of microwave energy.
This lightning surge of power will last only a fraction of a second, but, travelling at the speed of light, it will wipe out any enemy weapons systems over a radius of several hundred metres. The really clever bit, however, is that while their tanks, air defence radar, missile systems or communications networks will be rendered useless, the Iraqi personnel operating them will be left unharmed.
The so-called high-powered microwave (HPM) weapon, or ebomb, will be the most sophisticated new weapon to get its operational debut in Iraq during a campaign that promises to be the most high-tech ever fought. The last Gulf War may have marked the moment when space-age weapons - from laser-guided "smart" bombs to cruise missiles - arrived, but, as collateral damage figures later proved, the technologies were still largely in their infancy.
The microwave bomb remains shrouded in secrecy, having been under development since the early 1980s at the US air force's directed energy directorate, based at Kirtland air base in New Mexico. But a declassified research report written in 2000 by a former director of the air force's HPM programme makes it clear that the ebomb is no longer the stuff of science fiction.
Little detail is known about latest versions of the weapon but experts say it will use the energy from a conventional explosion to create a flash of microwave energy which travels in an arc in front of the missile. This energy travels into electronic equipment and fries the internal circuitry, either through the antennae, radar dome or other sensors, known as the front door, or through cracks, trailing wires or metal conduits, known as the back door. Every electronic system within the weapon's conical footprint will be affected, meaning that a single HPM can be used to attack multiple targets.
One of the key targets will be the fibre optic communications system which has been installed by Chinese contractors and which is one of the few technological advances enjoyed by Saddam's forces since 1991. Destroying this network early on would cut his forces off from the centre. Although they are extremely difficult to hit with conventional bombs, the bunkers must have outlets to the surface for communications, ventilation and electricity, all of which offer gateways for the microwave pulse.
Then there are the wider political imperatives which make the microwave bomb attractive for planners. Because it is equipment and not humans that are affected by the energy pulse, the weapon fits exactly with the US and British governments' commitment to target Iraqi weapon systems and infrastructure rather than troops.
That may tempt US commanders to use HPMs against the web of air defence sites around Baghdad. But defence experts say it is unlikely that they would be used so close to a civilian population where there is a risk of civil facilities such as hospital equipment or water treatment plants also being destroyed by the energy surge.
The microwave bomb is not the only advance since the last Gulf War. In 1991, only about 10 per cent of the bombs dropped on Iraq were precision-guided munitions. And, despite the claims of US commanders, the laser-guided bombs that were dropped were often inaccurate, killing many civilians, because the lasers could not penetrate cloud or battlefield smoke.
In this campaign, however, more than 80 per cent of the ordnance will be guided and will use far more reliable satellite guidance technology. The most common weapon will be the joint direct attack munition (JDAM) a tailkit which can convert a "dumb" freefall bomb into a precision smart weapon. The JDAM contains a tiny receiver which uses global positioning system satellites to steer the bomb to the target.
The satellite signals, unlike laser, are unaffected by cloud or smoke.
Other weapons will be far less sophisticated, relying on brute force rather than technological finesse.
Last week, the US released test images of a 21,000 lb bomb known as the massive ordnance air blast bomb or Moab but experts doubt whether the Moab will be ready in time for this campaign.
That will leave the job of bunker-busting to the 5000lb GBU-28.
The 19ft-long laser-guided munition was rushed into service during the last Iraq campaign and is capable of penetrating about 20ft of concrete or 100ft of earth. - (Guardian Service)