One of the most impressive feats during the race to the Moon in the 1960s was the creation of NASA's global tracking and data network. This network was responsible for tracking the astronauts to the Moon and back, giving to and receiving data and information from them. Fast Company's Charles Fishman details the network's creation:
As constructed and operated during Apollo, the network—NASA called it the STDN, the Spaceflight Tracking and Data Network—had 14 big antennas in sites ranging from Bermuda to Madrid to Guam. The three largest antennas, still in use, have surface areas two-thirds the size of a football field, tilted up in the air, aimed at the signals coming from Apollo.
STDN also had four specially constructed ships at sea—oil-tanker hulls hollowed out and retrofitted with huge tracking antennas, mounted bow to stern—and two satellites to help relay signals. During splashdown, as the capsules floated to the Pacific Ocean on parachutes (well beneath the range of land-based tracking antennas), NASA put eight airplanes aloft to maintain communication.
The tracking stations were linked by two-million miles of communication links: telephone wire, undersea cable, microwave towers. That’s enough communication line to circle the Earth 80 times, and it was the first global, high-speed data network. The system was designed and run by NASA’s Goddard Spaceflight Center in Maryland, just outside Washington, D.C. That’s where all the signals were collected from around the world and then piped from Goddard to Mission Control in Houston. They went back out through Goddard as well.
The network cost $370 million to assemble in the mid-1960s. For comparison, each lunar module cost about $100 million. It required 2,700 people to operate and relied on 39 Univac computers spread around the world to manage the signals pouring in. During the Apollo years, it cost $70 million a year to run. The phone bill alone, the cost of those two million miles of leased communications lines, was $50 million annually (almost $400 million in today’s dollars).
Now that is one impressive feat, in terms of operational capacity and financial cost.
image taken from Sunny Tsiao's Read You Loud and Clear! The Story of NASA's Spaceflight Tracking and Data Network