U.S. Air Force Senior Airman Jakob Miner, 1st Aircraft Maintenance Squadron crew chief, signals an F-22 Raptor to stop at a hydrogen pit for a hot pit refuel at Joint Base Langley-Eustis, Va., Jan. 6, 2017. Hydrogen pits are connected to underground pipes that allow fuel to flow from nearby storage tanks. (U.S. Air Force photo by Airman 1st Class Kaylee Dubois)