OPERATIONAL CONCEPT FOR HYDROGEN FUEL-BASED FULLY UNMANNED CARRIER AVIATION

Efforts to reduce dependence on existing fossil fuels and decouple from logistics trains are becoming critical for the U.S. military. Hydrogen, a potential alternative fuel, offers three interesting characteristics: it is the most energy-dense source short of a nuclear reaction; it can be used in ways that do not generate heat or harmful chemical substances; and it can be made from seawater. This study defines an operational concept for an unmanned carrier with unmanned aerial vehicles (UAVs) fueled by hydrogen and models this system to ascertain operational implications for a future fleet executing Distributed Maritime Operations as a hybrid force. An ExtendSim model is developed and used to analyze the operational concept with the proposed carrier's physical and functional attributes while assuming existing UAV technology. Operational availability is used as the fundamental comparison. The resulting analyses highlight three major findings. UAV maximum endurance is the most important factor in increasing operational availability. The second most important but closely related factor is fuel type, with liquid hydrogen fuel showing a 7% increase in operational availability over JP-5 for the explored scenarios. The third most important factor is the number of UAV maintenance bays. These three factors account for more than 80% of the statistical variability in the model and are important design points for operationalizing hydrogen as a future carrier aviation fuel.