NX-Control was the ground-based control center for flights of the NX Program. The facility, located within the Zefram Cochrane Space Flight Center on Earth, was operated by Starfleet Mission Control, under the command of then-Commodore Maxwell Forrest. Vulcan officials, representatives of the Vulcan Advisory Council, were also present. Due to security reasons, they were required to have special IDs in order to be present in the room.
All telemetry and communications from the NX test vehicles were directed to NX-Control. The pilot was often in communication with a fellow pilot who relayed instructions. Then-Commander Jonathan Archer was the director of the first flight past warp 2 by A.G. Robinson in the NX-Alpha in 2143. (ENT: "First Flight")
The set for NX-Control is reminiscent of real-life NASA mission control centers. The idea of a fellow pilot being the communicator to the mission is also borrowed from NASA; the CAPCOM is an astronaut who relays instructions to a crew in orbit.
In the final draft script of "First Flight", the room from where the missions were operated was referred to as "NX-Mission Control". However, the abbreviated name "NX-Control" is the only name given on screen. The script's list of sets additionally specified that the room was located in the NX-Launch Complex, in San Francisco. The script described the room itself as "A small but hi-tech control center [...] [containing] monitoring stations."
According to mission patches seen in the 602 Club, the motto of Starfleet Mission Control was "Res gesta par excellentia", or more likely "Res gesta per excellentiam", which translates to "Achieve through Excellence", one of the mottoes of NASA's mission control.
From the Star Trek Encyclopedia (4th ed., vol. 2, p. 93), "Like NASA's real-life mission-control rooms, the upper walls of NX Mission Control were decorated with mission and program emblems. These included the Earth Cargo Service, Zefram Cochrane's Phoenix from Star Trek: First Contact, the United Earth/UESPA emblem from the "The Cage" (TOS), and a mission patch for the first Earth-Saturn probe, mentioned in "Tomorrow is Yesterday". (TOS) [...] A "Starfleet Mission Control" emblem on the wall features the sigma symbol that represents teamwork to the real NASA mission control team, as well as their motto "Res Gesta Per Excellentiam", translating as "Achievement through Excellence". The room number on the door of the NX Mission Control room, 2306, was the same as the room number of the main Space Shuttle Mission Control Room at NASA's Johnson Space Center in Houston. Three-real life U.S. Navy sailors, voted "Sailors of the Year" from the aircraft carrier Enterprise, had cameo roles as VIPs present in the NX Mission Control room during Robinson's flight. They were James D. Frey, Kathleen J. Grant, and Thomas P. Hunt."