Command and Control
To assure a safe flight, each country had to establish a network to track its spacecraft and communicate with them.
This is a ground trace of Gagarin's flight path. During the first four years of Soviet human spaceflight, the U.S.S.R. relied only on ground stations within the country to track space flights. As a result, the cosmonauts were out of touch with ground control for about half of each orbit.
The United States developed a worldwide network of ground stations, ships, and aircraft. It provided nearly continuous contact between the astronaut and ground control during the early suborbital and orbital missions.