The Office of Naval Research has selected UTC Aerospace Systems for the continued development of a long-endurance propulsion system for unmanned undersea vehicles, the company said Wednesday. As part of the next phase of development, UTC Aerospace Systems has been tasked with the continued design and development of a proton exchange membrane-based fuel cell energy system for unmanned undersea vehicles with a 21-inch diameter. The proton system could replace battery systems by providing greater range and operational flexibility, said UTC…