EIELSON AIR FORCE BASE, Alaska – U.S. Air Force Capt. Bret Lindstrom, a 335th Fighter Squadron flight surgeon assigned to Seymour Johnson Air Force Base, N.C., listens to a patient’s heartbeat, May 4, 2017, during NORTHERN EDGE 2017 (NE17), at Eielson Air Force Base, Alaska. NE17 is Alaska’s premier joint training exercise designed to practice operations, techniques and procedures as well as enhance interoperability among the services. Thousands of participants from all the services, Airmen, Soldiers, Sailors, Marines and Coast Guardsmen from active duty, Reserve and National Guard units are involved. (U.S. Air Force photo/Staff Sgt. Ashley Nicole Taylor)