By Russ Bri= Northrop Grumman tests defense gear for commercial jets=0A=0A=0ABy Russ Bri= tt, MarketWatch=0ALast Update: 2:45 PM ET Jan 15, 2007=0A=0ALOS ANGELES (Ma= rketWatch) -- First, pilots behind barricaded doors with handguns, and now = laser beams to deflect missiles away from passenger jets?=0AThat appears to= be what's next for commercial aircraft as defense giant Northrop Grumman C= orp. started testing Monday on a system designed to further protect passeng= er jets from terrorist attacks.=0A GET QUOTES=0A Enter one or more symbols= =0A =0A=0AQuotes delayed up to 20 Minutes=0A=0A=0A=0A=0A=0A RELATED = QUOTES=0A=0A NOC69.58 +0.38 =0A=0A=0A=0A=0A=0A=0A Top MarketWatch=0A Headl= ines=0A=0AETF providers aim to crack the 401(k) market=0A=0AGE to buy aeros= pace arm of Britain's Smiths for $4.8 billion=0A=0ACORRECT: Broad gains fro= m Tokyo to Jakart=0A=0A=0A=0A=0A=0A=0AUnder a contract with the Department = of Homeland Security, Los Angeles-based Northrop (NOC: news) was to start t= he first flights of jet aircraft equipped with a detection system mounted u= nderneath its fuselage. The system's designed to detect a shoulder-fired mi= ssile launch and guide it away from the passenger jet within seconds.=0AWit= h more than two dozen terrorist groups identified as possessing shoulder-fi= red missile systems such as U.S.-made Stingers, the prospect of such an att= ack is key in the minds of U.S. officials.=0A"It's considered one of the to= p three threats by the Department of Homeland Security," said Jack Pledger,= Northrop's director of infrared countermeasures development. Roughly 40 co= mmercial or civil aircraft have been hit by shoulder-fired missiles since 1= 972, mostly in high-conflict regions such as Africa or the Middle East, he = added.=0ANorthrop's system, known as Guardian, is a derivative of other sys= tems already used on military aircraft. Northrop will test Guardian on a do= zen MD-10 jets over the next 14 months.=0AMonday's test and subsequent test= s will gauge how well the system interacts with other aircraft gear. Tests,= of course, will not consist of actual firing exercises; those were conduct= ed using an empty cable car at White Sands Missile Range in New Mexico. =0A= The cable car, which gave off a heat signal similar to those found in most = aircraft, was propped up on rails between two mountains at the missile rang= e. Pledger said the system experienced a 100% success rate under those cond= itions, and its military version has been successful in Middle East conflic= ts.=0AA missile launch is detected "within milliseconds," Pledger said. A t= racking device immediately hones in on the missile and a low-intensity lase= r beam is aimed at it, diverting it away from the aircraft, he said.=0A"It'= s a lot like a laser the dentist uses to whiten your teeth," he said.=0AIn = most cases, the entire process is designed to take place within a second or= two, before pilots or ground personnel are aware of the threat. Missiles u= sually will continue on an upward track and burn up in the atmosphere, alth= ough there may be cases where the projectiles will end up back on the groun= d, Pledger said. But missiles are likely to take a larger human toll if the= y strike an airplane, he added.=0AHomeland Security has mandated that no sy= stem cost more than $1 million per plane, but Pledger says Northrop's syste= m will ultimately come in "well below" that figure. That translates to a co= st of $1 per passenger for each flight, he said.=0AHe added that it would t= ake roughly three years to outfit the nation's fleet of roughly 4,000 plane= s with the devices.=0A=0ARuss Britt is the Los Angeles bureau chief for Mar= ketWatch.