Defense Advanced Research Projects Agency (DARPA) announced the completion of the initial phase of temporary underwater fiber-optics communications networks development. DARPA’s Tactical Undersea Network Architecture (TUNA) program aims to ensure connectivity when tactical networks are unavailable. Designed to withstand the pressure, saltwater, and currents of the ocean, the hair-thin fiber-optic cables being developed will last 30 days in rough ocean environment to provide essential connectivity until primary methods of communications are restored. The next phase calls for the demonstration of a prototype of the system at sea.