An F-35B Lightning II awaits refueling before a night operations exercise during F-35B Operational Testing (OT-1) aboard USS Wasp (LHD-1) May 20, 2015. Over the course of about two weeks, U.S. Marines, U.K. military and industry partners will evaluate the full spectrum of F-35B measures of suitability and effectiveness, as well as assessing the integration of the aircraft into the spectrum of amphibious-based flight operations. (Marine Corps photo by Cpl. Anne K. Henry/RELEASED)