April 3, 2008 Being shot out of the sky with a surface-to-air missile might not be at the forefront of your mind when traveling on a commercial airliner, but with shoulder-mounted, infra-red anti-aircraft rockets selling for as little as US$5000 in trouble spots around the world, it's perhaps surprising that it's only happened a few dozen times in recent years. Once launched, such a missile travels at twice the speed of sound towards its target, so countermeasures must be automatic and instant - which brings us to Northrop Grumman's GUARDIAN system. This anonymous-looking pod provides 360-degree laser-based missile defense for commercial airliners for a total cost of around a dollar per passenger over the aircraft's service life.

According to the Federation of American Scientists, Man-Portable Air Defense Systems (MANPADS, or shoulder mounted guided anti-aircraft missiles) have already caused as many as 1000 civilian deaths in the hands of terrorists around the world. Such weapons are easy and cheap to procure and can be set up and fired very quickly. Once fired, they follow the heat signature of an aircraft with a very effective infra-red guidance system, and a hit is almost certainly a kill, bringing the entire aircraft down.

The effective range of a MANPADS system is such that a commercial plane can be targeted and brought down from beneath the flight path up to 50 miles either side of an airport - meaning that airliners are exposed to considerable risk in hot zones around the world.

In order to effectively protect civilian aircraft against MANPADS attacks, US Defence contractor Northrop Grumman has developed a self-contained, autonomous and affordable missile defence unit that can bolt on beneath any airliner to automatically and reliably neutralize missile threats coming from any point on the ground.

The GUARDIAN system is based on Northrop Grumman's AN/AAQ-24 NEMESIS Directional Infrared Countermeasure system, which is considered the most advanced aircraft-mounted missile defence unit available, able to deal with the most recent guided missile threats.

Once attached to an airliner and activated, the GUARDIAN system constantly scans the airspace below the aircraft for threats. If one or more threats are detected, they are tracked until the system confirms that they are guided missiles. At this point, an eye-safe laser sends out a jamming signal that upsets the missile's infrared guidance system and turns the missile away from the airplane.

The NEMESIS and multi-band laser jamming technology behind the GUARDIAN system has endured extensive and highly successful testing, including over 100 successful live-fire missile engagements in combat operations aboard military aircraft from the USA, UK, Australia and Denmark.

Last week, Northrop Grumman announced that the GUARDIAN system was fully tested, FAA certified and ready to be deployed on airline fleets around the world. The system's entire life cycle, including installation, maintenance, removal and disposal costs a little under US$1 million per unit - but over the 20-year lifespan of the aircraft it protects, that comes down to around a dollar per passenger flown, or roughly the raw cost of a bag of nuts and a soda. Which would you prioritize?

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