How does sputnik 1 work?

Sputnik 1, launched by the Soviet Union in 1957, was the first artificial satellite and worked by transmitting radio signals back to Earth. It contained a simple radio transmitter that emitted pulsating signals at a frequency of 20.005 MHz. The satellite's design included a metal sphere with four long antennae, which helped it send signals as it orbited the Earth. The signals were received by ground stations, allowing scientists to study its trajectory and gather data about the upper atmosphere.