190506-N-PO203-0164 NATIONAL HARBOR, Md. (May. 6, 2019) Rear Adm. David Hahn, chief of naval research, moderates a panel titled, Space - The Final Frontier, at the Sea-Air-Space exposition. The annual exposition, hosted by the Navy League of the United States, brings together key military decision makers, the U.S. defense industrial base and private-sector U.S. companies for an innovative, educational, and professional maritime based event. (U.S. Navy photo by John F. Williams/Released)