Northrop Grumman has completed 6,000 on-aircraft operational flight hours for the Guardian Counter-Man Portable Air Defense System (C-MANPADS) currently installed on wide-body cargo aircraft in commercial revenue service. Under the terms of the operational test and evaluation portion of the U.S. Department of Homeland Security's C-MANPADS program, which concludes in March 2008, Northrop Grumman has built 12 Guardian missile defense systems, with installation to date on seven MD-10 aircraft. The purpose of the T&E phase is to collect reliability data in an operational environment. Guardian utilizes proven military technology to defend commercial aviation from anti-aircraft, shoulder-fired missiles. Guardian directs a non-visible, eye-safe laser to the seeker of the incoming missile, disrupting its guidance signals. Northrop Grumman has used a ground-based electronic missile surrogate to simulate the launch of a shoulder-fired missile toward aircraft during takeoff and landing. The tests were performed on an MD-11, an MD-10 and a B-747 aircraft. In each test, the Guardian system functioned as designed, automatically detecting the simulated launch and mock missile.