Under Secretary of the Air Force, Matthew P. Donovan, looks at a C-130 turbo-prop engine through a set of HoloLens goggles during a visit to the 361st Training Squadron’s aircraft propulsion apprentice course at Sheppard Air Force Base, Texas, Feb. 14, 2019. Sheppard is leveraging the technology as another tool to enhance training and develop Mach-21 Airmen in areas such as aircraft maintenance and civil engineering. (U.S. Air Force photo by Airman 1st Class Madeleine E. Remillard)