Short answers, pulled from the story.
Arthur C. Clarke is credited with inventing the concept. In October 1945 he published an article titled "Extraterrestrial Relays" in the British magazine Wireless World, describing how artificial satellites in geostationary orbit could relay radio signals around the Earth. The geostationary orbital band is now called the Clarke Belt in his honor.
Project SCORE, launched on the 18th of December 1958 and led by the Advanced Research Projects Agency, was the first satellite purpose-built to actively relay communications. It used a tape recorder to store and retransmit voice messages, including a Christmas greeting from President Dwight D. Eisenhower. Its batteries failed on the 30th of December 1958 after eight hours of actual operation.
Geostationary satellites orbit at 22,236 miles above Earth's equator. At that altitude, a satellite's orbital period matches Earth's rotation exactly, making the satellite appear stationary in the sky. Ground antennas can be fixed in place and aimed permanently at the satellite without any tracking mechanism.
Syncom 3, launched on the 19th of July 1964 by NASA, was the first geostationary communications satellite. It provided television coverage of the 1964 Summer Olympics across the Pacific. The first commercial geostationary satellite for telecommunications was Intelsat I, also known as Early Bird, launched on the 6th of April 1965.
Geostationary satellites sit above the equator and appear progressively lower on the horizon at high latitudes, dropping below the horizon entirely for much of Russia. The Molniya orbit is a highly elliptical path that keeps a satellite over the northern hemisphere for six to nine hours per revolution, providing reliable coverage over Russian territory and high-latitude regions. A constellation of three Molniya satellites can provide uninterrupted coverage.
Satcom 1, launched in 1975 by RCA Americom, was used by early cable channels including WTBS, HBO, CBN, and The Weather Channel to distribute programming to cable headends nationwide. Broadcast networks ABC, NBC, and CBS also used it to reach local affiliates. Satcom 1 carried 24 transponders, twice the capacity of its domestic competitor Westar 1, resulting in lower per-transponder costs.