Satellites were man-made and unmanned objects in space. They were used for many different applications.
In 1957, the first satellite, Sputnik, was launched by the Soviet Union. Sputnik was primarily a beacon satellite that transmitted a radio signal that could be tracked on the ground. As a matter of fact, many early satellites were beacon satellites. These beacon satellites were the precursors to the Global Positioning System (GPS). When Sputnik was launched, the United States and the Soviet Union were embroiled in a Cold War. They launched spy satellites to spy on each other and other countries. Some of these later on had scientific purposes, too. They could what was going on on the surface of the planet. This led to the first weather satellites. But the best known application for artificial satellites was communications. Early communications satellites used reflective mirrors. Later version could receive and retransmit signals and were used in deep space relays to reduce atmospheric interference. Some satellites were automated laboratories for testing new applications. In the late Cold War, there were also observatory satellites. These space telscopes would later include the Hubble Space Telescope. Another Cold War era satellite was the stealth satellites of the USSR. They would move undetected and explode whe it reached its target. After the Cold War, satellites would see new applications. Satellites also got smaller. This gave birth to the microsatellite.
Tech Level: 10-12
Microsatellites were satellites smaller than 100 kg. One of the earliest was LauncherOne designed by Virgin Galactic. They were first used to supply space stations. They were orbital tool sheds or cache satellites were ahead of space stations. As microsatellites became more sophisticated, they could be used for many applications. It was basically the Moore's Law of artificial satellites. Some satellites were mirrors launched by Russia to provide for urban communities in Northern Russia. There were also microsatellites that made the first use of tether propulsion. Some were skimmers that collected atmospheric particles. These were used to power tank stations. During World War III, microsatellites also had a military application as weapons platforms. Weapons platforms used directed-energy weapons to shoot down other satellites and ICBMs. They also had missiles and guns for targeting the surface. After World War III, weapons platforms were also used for a better purpose: asteroid destruction. Any asteroids and comets that posed a major threat would be destroyed to protect Earth. This did not always work. At the same time, microsatellites were also being used to create energy. The first solar power satellites. They produced energy from the sun and sent it to Earth. There were other applications for both conventional satellites and microsatellites. One was to de-orbit dead and disabled satellites. Conventional satellites did most of that work while most microsatellites in the fields were junk eaters that specialized in eliminating small debris and satellites. This cleaned up much of the debris in space. There were also automated orbital factories that could produce other microsatellites for different applications. One applications was very scientific. Automated orbital factories produced gravity wave detectors which were successful in detecting gravity waves. This later revolutionized physics and led to artificial gravity and faster-than-light space travel. They also built electromagnetic cargo launchers which were coilguns that sent cargo to space stations. Some satellites were, in fact, redirected asteroids that were used for mining raw materials. There were also satellites that stayed in one place. They were called statites.