U.S. Air Force Maj. Tom “Vito” Massa (right), 633rd Aerospace Medical Squadron Physiological Flight commander, flies an F-22 Raptor profile on a reduced oxygen breathing device with assistance from 1st Lt. Kimberly Dowd (left), 633rd Aerospace Medical Squadron aerospace physiologist, at the Physiological Training Center at Langley Air Force Base, Va., Feb. 14, 2012. The ROBD exposes aviators to lower concentrations of oxygen, mimicking atmospheric gaseous concentrations at various altitudes. (U.S. Air Force photo by Senior Airman John D. Strong II/Released)