The U.S. Army's Mobile Tactical High-Energy Laser (THEL) program scored another first recently when the system detected, tracked and destroyed two artillery shells fired from guns several miles away. The heat from the laser caused the explosives in the shell to detonate. The artillery shells were traveling at about 1300 feet a second (half the speed of a rifle bullet.) Two years ago, the Mobile Tactical High-Energy Laser has shot down single and multiple artillery rockets (which travel slower and are larger targets for the radar to pick up.) The Mobile Tactical High-Energy Laser isn't really mobile right now. It is movable though, with several large trucks. But the system has proved it can do the job. It will take another five years to develop a more light weight power source and a more reliable radar and fire control system. Right now, the range is too short (a few kilometers) and the laser has to be on the target too long (a few seconds) to make a dent in a large scale use of rockets or artillery. There's also the problem of lasers being weakened by clouds, fog, mist or even artificial smoke. For these reasons, Israel is contributing money and technology to the project in order to obtain a system useful against terrorists using a few rockets against Israeli civilians. In fact, THEL will probably see more use in the "anti-terrorist" role than in combat. After that, it will be ready for use against small aircraft (like recon UAVs). It will probably be some ten years or more before the system is ready for regular combat use.