Against the backdrop of the war on terrorism, an expanding group of government researchers is at work on a nationwide sensor network that someday could provide a real-time early-warning system for a wide array of chemical, biological and nuclear threats across the United States. Drafts of the objectives and milestones for the sensor network project are already circulating among key scientists at national labs and within an emerging technology branch inside the newly formed Department of Homeland Security that is coordinating the effort. While details of the program are not likely to be made public until at least this fall, the national labs have been working for more than a year on the core issues in materials, sensors, networks and electronics, and already have set up several field trials of prototype networks. Project researchers hope to use microelectromechanical systems (MEMS) and nanotechnology to create a suite of low-cost yet highly accurate biological and chemical sensors. On the networking front, they foresee an Internet-like peer-to-peer network with multilevel security and quality-of-service guarantees, spanning wireless, wired and satellite links. Full Story