On this day, 54 years ago, on April 19, 1971 (March 24, 1971 in the lunar calendar), the Soviet "Salute-1" navigation sky station was launched for the first time. The Soviet Union first launched the Salute-1 space station on April 19, 1971. It is a manned artificial satellite operating in fixed orbit, used as a base for scientific observations and experiments, and can be used to fuel other spacecraft or launch satellites and missiles from it. The Salute-1 space station weighs 8610 kilograms and has a total length of 7.6 meters. It was originally designed to operate in permanent orbit, but due to its low orbit, it failed to enter the Earth's atmosphere six months later.