Trekipedia

U.S.S. Enterprise CVN-65

Part of the United States Navy in the late 20th and early 21st centuries on Earth, the Enterprise was a nuclear-powered Nimitz class aircraft carrier from which Starfleet officers Chekov and Uhura “borrowed” high-energy photons in order to recrystallize the failing dilithium crystals in their ship in order to return to their proper time period. During the covert operation while the Enterprise was docked at a Naval Base in Alameda, Chekov was captured by Naval personnel, but eventually escaped.^[1]