 Radio signals from the satellite were studied by the Ionospheric Radio Measurement and Control Centre, established the previous year.A station for optical tracking of "Sputnik 1" was set up in November 1957 on Plana mountain.Influenced by these events and publications of the International Astronautical Federation, engineer Georgi Asparuhov and Bulgarian Air Force captain Docho Haralampiev decided to introduce the wider public to the topic of space exploration.