U.S. Air Force Master Sgt. Christopher Hoopes, 1st Operations Group Aerospace and Operational Physiology flight chief operates the Reduced Oxygen Breathing Device at Joint Base Langley-Eustis, Virginia, June 13, 2019. The ROBD is designed to simulate high altitude environments to induce hypoxia symptoms. (U.S. Air Force photo by Senior Airman Tristan Biese)