As the truck growled up another rise and started back down again, Zych reached up and flicked a wiper switch to brush away the slurry, then put his hands back in his lap. "We haven't automated those yet," he explained, referring to the windshield wipers, as the robotic truck reached the bottom of the hill and executed a perfect hairpin turn. Ten years of war in Afghanistan and Iraq have put a spotlight on the growing use of unmanned systems in the skies over the battlefield, from the high-flying Global Hawk to the lethal Predator aircraft and the hand-launched Raven. But on the ground, thousands of small, remotely operated robots also have proven their value in dealing with roadside bombs, a lethal threat to U.S. troops in both wars. Of more than 6,000 robots deployed, about 750 have been destroyed in action, saving at least that many human lives, the Pentagon's Robotics Systems Joint Program Office estimates.