The Trident missile is a submarine-launched ballistic missile equipped with multiple independently targetable reentry vehicles . Originally developed by Lockheed Missiles and Space Corporation, the missile is armed with thermonuclear warheads and is launched from nuclear-powered ballistic missile submarines . Trident missiles are carried by twelve United States Navy Ohio-class submarines, with American warheads, as well as four Royal Navy Vanguard-class submarines, with British warheads. The missile is named after the mythological trident of Neptune.