160517-N-HU377-026 NATIONAL HARBOR, Md. (May 17, 2016) Secretary of Defense (SECDEF) Ash Carter speaks during a luncheon at the 2016 Sea-Air-Space Expo, the first time in six years that SECDEF has attended the exposition. The Sea-Air-Space Exposition is an annual event that brings together key military decision makers, the U.S. defense industrial base and private-sector U.S. companies for an innovative and educational maritime based event. (U.S. Navy photo by Mass Communication Specialist 2nd Class Dustin Knight/Released)