U.S. Air Force B-2 Spirit crew chiefs assigned to the 509th Aircraft Maintenance Squadron perform pre-takeoff inspections during Exercise Global Thunder 17 (GT17) at Whiteman Air Force Base, Mo., Oct. 27, 2016. Exercise Global Thunder is U.S. Strategic Command’s annual field training and battle staff exercise to train Department of Defense forces and assess joint operational readiness. GT17 provides training opportunities and exercise scenarios for all USSTRATCOM mission areas, with a specific focus on strategic readiness.