The growing fear of terrorists firing portable anti-aircraft missiles at airliners has provided a marketing opportunity for the only existing defensive system that does not use flares. For over a decade there have been missile detectors, radars or heat sensors that detect fast moving objects behind an aircraft and alert the pilot. Until recently, the countermeasure was to release flares. Most of the time, the flares would lure the missile, which homes on heat, away from the aircraft's engines. But the Nemesis DIRCM (Directed Infra-red Countermeasures) system uses a ten pound laser, drawing 320 watts of power, to replace the flares. This eliminates the fire hazard for aircraft taking off or landing over built up areas. When a missile is detected, the laser is directed at the front of the missile (where the heat seeking mechanism is) and directs the missile away from the aircraft. Unfortunately, because this is new technology, each Nemesis system costs over two million dollars. But that are about 500,000 portable anti-aircraft missiles out there, most of them old Soviet models. The vast majority of these missiles can be easily deceived by Nemesis. If enough (say thousands) Nemesis systems are purchased, the unit cost will probably come down to $100,000 or less.