Which scientist has proven that space exploration is possible with a rocket?

The first scientist who proved that the rocket will become a real means of space exploration was our compatriot, the founder of modern cosmonautics Konstantin Eduardovich Tsiolkovsky (1857-1935).

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.