In 1973, the Timation program was merged with the Air Force's 621B program, with the Air Force being named the Executive Service, to form the NAVSTAR GPS program. NRL'S Timation 3 satellite was redesignated the NTS-1 (Navigation Technology Satellite 1) and was launched in the summer of 1974 in connection with the NAVSTAR effort. NTS-1 had two rubidium-vapor frequency standards (clocks), while the earlier Timation satellites had carried selected high-performance crystal oscillator clocks to test the NRL theory.