Vacuum Tubes
Vacuum tubes, also known as thermionic valves, are electronic devices that control the flow of electric current through a vacuum in a sealed container. They were widely used in early electronic devices, including radios, televisions, and computers, before being largely replaced by solid-state electronics. Vacuum tubes consist of a cathode, an anode, and one or more control grids. When a voltage is applied to the cathode, it emits electrons, which are attracted to the anode. The control grids can be used to modulate the flow of electrons, allowing vacuum tubes to function as amplifiers or switches. In space and astronautical engineering, vacuum tubes were used in early satellite and space exploration missions, including the first satellite, Sputnik 1, and the Apollo Guidance Computer. However, due to their size, weight, and power requirements, vacuum tubes have largely been replaced by solid-state electronics in modern spacecraft.
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