As early as the17th century, Newton had imagined how an object could go around the earth: erect a powerful cannon on a high mountain. If the cannon is fast enough, it will not fall, but circle around the earth and even fly out of it. Newton also calculated that if the projectile wants to make a circular motion around the earth without landing, the speed must reach 7.9 km/s, which is the first cosmic speed; To fly out of the earth, you must reach 1 1.2 km/s, which is the second cosmic speed.
In his spare time, tsiolkovsky was fascinated by all kinds of scientific research and calculation, especially the theoretical research on space navigation and rocket propulsion. 1903, he published an epoch-making book in the history of modern space, Studying Space with Jet Tools. In the book, the relationship between rocket flight speed and rocket engine jet speed, rocket mass and fuel mass-Tsiolkovsky formula is put forward. From the launch of the first rocket to the present, the design and manufacture of every rocket in the world can not be separated from the guidance of this formula.
Tsiolkovsky believes that in order to overcome the gravity of the earth and enter the orbit around the earth, it is necessary to use multistage rockets with liquid hydrogen and liquid oxygen as propellants to achieve the necessary speed. After the rocket propellant burns in the combustion chamber, it produces high temperature and high pressure gas, which is accelerated through the nozzle and produces reaction force to push the rocket forward. It's like recoil when spraying water with a hose or shooting with a gun. Tsiolkovsky not only designed rocket propulsion and multi-stage rocket scheme, but also put forward the idea of sealed cabin and space station, as well as the idea of sealing ecological circulation system and providing oxygen and food for astronauts.
If tsiolkovsky solved the theoretical problems of rockets, Goddard and Wernher wernher von braun solved the technical problems of rockets.
Robert goddard is the earliest rocket scientist in the United States. He started theoretical research on rocket dynamics from 65438 to 0909. Three years later, he ignited a solid fuel rocket in a vacuum glass container, which proved that the rocket could work in a vacuum. 19 19 His report "The Way to Reach Extremely High" expounded the basic mathematical principles of rocket flight. 1in March, 926, Goddard successfully launched the first rocket: using gasoline and liquid oxygen as propellants, it was about 3.4 meters long and had a launch mass of 4.6 kilograms. The flight duration is about 2.5 seconds, the maximum altitude is 12.5 meters, and the flight distance is 56 meters. This rocket proved the feasibility of liquid propellant, making it the originator of modern rockets. Before the death of 1945, Goddard made 34 rocket launches, but most of them ended in failure and failed to get official funding. Later, in order to commemorate the pioneer of rocket science, NASA named the large research center in Greenbelt, Maryland, the eastern United States as "Goddard Space Flight Center".
Compared with Goddard, Wernher wernher von braun is much luckier. He was born in Germany on 19 12. /kloc-When he was 0/6 years old, he saw the book "Rocket to Interstellar Space" by German space pioneer and rocket expert hermann oberth, and he became fascinated with interstellar travel. From 65438 to 0930, Braun participated in the German Space Travel Society initiated by Aubert at the Technical University of Berlin, and assisted Aubert in conducting liquid rocket tests. His graduation thesis discussed the theory and experiment of liquid rocket engine in detail, and was rated as an excellent thesis. During World War II, he led the development of the German V-2 rocket. V-2 rocket uses alcohol and liquid oxygen as propellants, with total length 14m, launch mass 13t, warhead 1t and maximum flight trajectory of 80 ~ 100km. After World War II, Wernher wernher von braun went to the United States to lead the American space industry. 1946, the United States launched a V-2 rocket. The rocket flew to an altitude of 80 kilometers and was used to observe the ultraviolet rays of the sun, thus opening a new chapter in space science.