In the19th century, a great Russian scientist was named tsiolkovsky. In 1883' s paper Outer Space, he concluded that interstellar space is vacuum and only rockets can fly. 1903 published the book "exploring space with jet devices", and put forward the basic principle of rocket motion in free space. This is the famous "Chase Formula", which plays a very important fundamental role in space science. He put forward the idea of multi-stage rocket, and expounded the speed that human beings must obtain to overcome the gravity of the earth (the first cosmic speed, also called the circumnavigation speed, is 7.9 km/s, and when it reaches this speed, it can move around the earth. The second cosmic speed is 1 1.2 km/s, and the second cosmic speed is 1.2 km/s. It can fly to other planets or orbit around the sun. Third cosmic velocity, 16.7 km/s, at this speed, the aircraft can get rid of the sun's gravity and fly to the outer space of the solar system. ) At this time, people have already seen 1000 meters in front of them.

Tsiolkovsky's epitaph is engraved with his famous words: "The earth is the cradle of mankind, but mankind cannot live in the cradle forever. At first, he will carefully cross the atmosphere, and then he will conquer the solar system. "