These three men are knowen for there work with the first liquid or solid propelled rockets?

Answer 1

Konstantin Eduardovich Tsiolkovsky

(17 September 1857 – 19 September 1935) was a Russian and Soviet rocket scientist and pioneer of the astronautic theory. He is considered to be one of the founding fathers of rocketry and astronautics. During his lifetime he published approximately 90 works on space travel and related subjects.

Among his works are designs for rockets with steering thrusters, multistage boosters, space stations, airlocks for exiting a spaceship into the vacuum of space, and closed-cycle biological systems to provide food and oxygen for space colonies. In 1926–1929, Tsiolkovsky solved the practical problem of the role played by rocket fuel in getting to escape velocity and leaving the Earth. It turned out that the finite speed of the rocket depends on the rate of gas flowing from it and on how many times the weight of the fuel exceeds the empty weight of the rocket. Tsiolkovsky championed the idea of the diversity of life in the universe and was the first theorist and advocate of human space exploration.

Hermann Julius Oberth

(25 June 1894 – 28 December 1989) was an Austro-Hungarian-born German physicist and engineer. Influenced by Verne's books and ideas, Oberth constructed his first model rocket as a school student at the age of 14. In his youthful experiments, he arrived independently at the concept of the multistage rocket, but he lacked then the resources to pursue his idea on any but a pencil-and-paper level.

Robert Hutchings Goddard

(October 5, 1882 – August 10, 1945) was an American professor, physicist, and inventor who is credited with creating and building the world's first liquid-fueled rocket, which he successfully launched on March 16, 1926.