1.   Apart from its promise of an off-the-shelf technology that can defeat missiles, the Air Force is excited about the airborne laser concept because of its relatively low cost.

2.   Boeing officials declined to comment on whether Rockwell engineers will eventually work on the airborne laser program.

3.   -- An airborne laser missile-defense system.

4.   But the Global Positioning System and compact airborne lasers have made it feasible to track glaciers from the air.

5.   If the prototype performs as expected, the Air Force plans to buy seven airborne laser systems.

6.   Of these two weapons, only the airborne laser is in active development.

7.   One area of redundancy, however, involves a project to develop an airborne laser to shoot down missiles.

8.   Some scientists have suggested using an airborne laser to cut up asteroids, while others have talked about obliterating the mass altogether with a nuclear missile.

9.   The additional money could accelerate research in other fields, supporters of missile defense argue, including naval defenses, airborne lasers and space-based weapons.

10.   The airborne laser consists of infrared light, invisible to human eyes.