Short answers, pulled from the story.
The Spacecraft Tracking and Data Acquisition Network, abbreviated STADAN, was a NASA system built in the early 1960s for long duration, highly available space to ground communication. It gave ground controllers about fifteen minutes of contact with a spacecraft during each ninety minute orbit.
NASA established STADAN in the early 1960s as a follow on to the earlier Minitrack network, which had tracked Sputnik, Vanguard, Explorer, and other early missions between 1957 and 1962.
STADAN stations were spread across the globe, including sites in Chile, Bermuda, South Africa, Australia, the United States, Canada, Ecuador, Peru, Madagascar, England, Ascension Island, Pakistan, and Greece. The Network Operations Control Center that ran the system sat at Goddard Space Flight Center in Greenbelt, Maryland.
STADAN's roughly fifteen minute contact windows per orbit worked for uncrewed satellites but were not enough for crewed missions, which needed far more data collection time. In May 1971, NASA merged STADAN with the Manned Space Flight Network to form the Spaceflight Tracking and Data Network, or STDN.
Most STADAN stations were phased out in the early 1980s as the Tracking and Data Relay Satellite System, or TDRS, took over tracking of satellites in low Earth orbit. The Deep Space Network handled crewed spacecraft farther than 10,000 miles from Earth, such as the Apollo missions, alongside its main job of collecting data from deep space probes.
STADAN provided about fifteen minutes of space to ground communication during each ninety minute orbit period. That was enough for uncrewed spacecraft but insufficient for crewed missions, which needed considerably more contact time.