170222-N-OH262-211 ATLANTIC OCEAN (Feb. 22, 2017) Navy medical professionals assigned to the hospital ship USNS Comfort (T-AH 20) prepare to perform emergency surgery on a simulated casualty during a mass casualty drill. Comfort's underway period was part of the 2017 Comfort Exercise (COMFEX). The exercise is a quarterly training battery designed to keep the medical personnel, support staff and civil service mariners who serve aboard the ship proficient in their duties. Comfort provides an afloat, mobile, acute surgical medical facility when called upon to the U.S. military, and hospital services to support U.S. disaster relief and humanitarian operations worldwide. (U.S. Navy photo by Bill Mesta/Released)