Fuel-Cell-Powered all Electric UAS Launched from Submerged Submarine

The U.S. Naval Research Laboratory (NRL) with funding from SwampWorks at the Office of Naval Research (ONR) and the Department of Defense Rapid Reaction Technology Office (DoD/RRTO) demonstrated the launch of an all-electric, fuel cell-powered, unmanned aerial system (UAS) from a submerged submarine. From concept to fleet demonstration, this idea took less than six years to produce results at significant cost savings when compared to traditional programs often taking decades to produce results.

The NRL XFC UAS was deployed from the submerged submarine USS Providence; in the picture, the NRL developed XFC unmanned aircraft is vertically launched from a 'Sea Robin' launch vehicle (bottom right). The folding wing UAS autonomously deploys its X-wing airfoil and after achieving a marginal altitude, assumes horizontal flight configuration. The successful submerged launch of a remotely deployed UAS offers a pathway to providing mission critical intelligence, surveillance and reconnaissance (ISR) capabilities to the U.S. Navy's submarine force.

"Developing disruptive technologies and quickly getting them into the hands of our sailors is what our SwampWorks program is all about," said Craig A. Hughes, Acting Director of Innovation at ONR. "This demonstration really underpins ONR's dedication and ability to address emerging fleet priorities."

Operating under support of the Los Angeles class USS Providence (SSN 719) and the Naval Undersea Warfare Center-Newport Division (NUWC-NPT), the NRL developed XFC UAS—eXperimental Fuel Cell Unmanned Aerial System—was fired from the submarine's torpedo tube using a 'Sea Robin' launch vehicle system. The Sea Robin launch system was designed to fit within an empty Tomahawk launch canister (TLC) used for launching Tomahawk cruise missiles already familiar to submarine sailors.

Once deployed from the TLC, the Sea Robin launch vehicle with integrated XFC rose to the ocean surface where it appeared as a spar buoy. Upon command of Providence Commanding Officer, the XFC then vertically launched from Sea Robin and flew a successful several hour mission demonstrating live video capabilities streamed back to Providence, surface support vessels and Norfolk before landing at the Naval Sea Systems Command Atlantic Undersea Test and Evaluation Center (AUTEC), Andros, Bahamas.

"This six-year effort represents the best in collaboration of a Navy laboratory and industry to produce a technology that meets the needs of the special operations community," said Dr. Warren Schultz, program developer and manager, NRL. "The creativity and resourcefulness brought to this project by a unique team of scientists and engineers represents an unprecedented paradigm shift in UAV propulsion and launch systems."

The NRL previously completed a successful flight test of the XFC UAS. During the initial flight test, the XFC UAS was airborne for more than six hours. NRL's Chemistry and Tactical Electronic Warfare Divisions are developing the XFC UAS as an expendable, long endurance platform for Intelligence, Surveillance and Reconnaissance (ISR). Compared to internal combustion powered vehicles, battery powered UAS are inherently stealthy in that they are relatively free of noise and thermal signature, and are easy to start, operate and maintain. However, they have poor payload capacity and endurance. The electrically powered UAS could have more tactical utility and be a platform for ISR if endurance could be increased.

NRL and its fuel cell development and manufacturing partner, Protonex Technology Corporation have addressed these issues by developing a hydrogen fuel cell power plant system that greatly extends endurance and permits increased payload capacity. The technology has been successfully integrated into the XFC UAS, a folding wing, expendable UAS that has a small footprint with a standard lightweight rail launcher. The non-hybridized power plant supports this fully autonomous aircraft and an EO/IR payload for a flight endurance that enables relatively low cost, low altitude, ISR missions of up to seven-plus hours in its current configuration. In its final form, the XFC will be capable of self-launching from a folded configuration with loiter speed of 30 knots and a dash speed of 52 knots.

The NRL Chemistry and Tactical Electronic Warfare Divisions team includes the design-builder of the Sea Robin, Oceaneering International Inc., Hanover, Md.; the fuel cell developer Protonex Technology Corp., Southborough, Mass.; and NUWC-NPT's Autonomous and Defensive Systems Department for Temporary Alteration (TEMPALT) and test demonstration support.