The NASA (Ground) Communications System (NASCOM) manages terrestrial communications between ground stations, mission control centers, and other elements of spacecraft ground segments. Established in 1964, NASCOM provides worldwide, near real-time, transmission of commands, telemetry, voice, and television signals. It is managed out of NASA's Goddard Space Flight Center in Greenbelt, Maryland.

The Spacecraft Tracking and Data (Acquisition) Network was established by NASA in the early 1960s to satisfy the requirement for long-duration, highly available space-to-ground communications. The network was the “follow-on” to the earlier Minitrack, which tracked the flights of Sputnik, Vanguard, Explorer, and other early space efforts (1957–1962). Real-time operational control and scheduling of the network was provided by the Network Operations Control Center (NOCC) at the Goddard Space Flight Center (GSFC) in Greenbelt, Maryland.