180612-N-BR505-681 WAIKOLOA, Hawaii (June 12, 2018) The Solar-Soaring unmanned aerial vehicle (UAV) is on display during the World Conference on Photovoltaic Energy Conversion. During the conference, U.S. Naval Research Laboratory displayed its use of solar cell technology on the endurance-enhancing technology for UAVs. (U.S. Navy photo by Raeanna Morgan/Released)