Nebraska researchers test new firefighting tool _ drones

Researchers in Nebraska tested a new tool on Friday that could eventually help in fighting grass fires -- drones. A team from the University of Nebraska-Lincoln flew an unmanned aircraft over the prairie at the Homestead National Monument of America on Friday, dropping ping pong-like balls filled with a chemical mixture to ignite brush-clearing grass fires. Local and federal officials are interested in the technology because it could help clear overgrown vegetation in rugged, hard-to-reach terrain, said Michael Johnson, a spokesman for the National Park Service. The balls are filled with a chemical powder, potassium permanganate, before they're loaded into the drone. During flight, the aircraft pierces the ball with a needle and injects it with another chemical, glycol, before releasing it.