190506-N-TV402-0001 NATIONAL HARBOR, Md. (May 6, 2019) U.S. Air Force Gen. Terrence O’Shaughnessy, commander of U.S. Northern Command, delivers remarks during the Arctic: Strategies for the Frozen Domain panel at the Sea-Air-Space (SAS) 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 Mass Communication Specialist 2nd Class Timothy Hale/Released)