The first person to establish many of the main ideas of modern rocketry was a Russian
schoolteacher, named Konstantin Tsiolkovsky (1857–1935). Most of his work was done even
before the first airplane flight, which took place in 1903. Tsiolkovsky realized that in order
for rockets to have enough power to escape Earth’s gravity, they would need liquid fuel
instead of solid fuel. He also realized that it was important to find the right balance between
the amount of fuel a rocket uses and how heavy the rocket is. He came up with the idea
of using multiple stages when launching rockets, so that empty fuel containers would drop
away to reduce mass. Tsiolkovsky had many great ideas and designed many rockets, but he
never built one.
The second great rocket pioneer was an American, named Robert Goddard (1882–1945). He
independently came up with some of the same ideas as Tsiolkovsky, such as using liquid fuel
and using multiple stages. He also designed a system for cooling the gases escaping from
a rocket, which made the rocket much more efficient. Goddard was more practical than
Tsiolkovsky and built rockets to test his ideas. Figure23.18shows Goddard with the first
rocket to use liquid fuel. This rocket was launched on March 16, 1926 in Massachusetts.
Over a lifetime of research, Goddard came up with many innovations that are still used in
rockets today.
Figure 23.18: (Left) Robert Goddard launched the first liquid-fueled rocket on March 16,
1926; (Right) This schematic shows details of Goddard’s rocket. ( 9 )
The third great pioneer of rocket science was a Romanian-born German, named Hermann
Oberth (1894–1989). In the early 1920’s, Oberth came up with many of the same ideas
as Tsiolkovsky and Goddard. His early work was not taken seriously by most scientists.
Nonetheless, Oberth built a liquid-fueled rocket, which he launched in 1929. Later, he
joined a team of scientists that designed the rocket shown inFigure23.19for the German
military. This rocket, first called the A-4 and later the V-2, played a major role in World War
II. The Germans used the V-2 as a missile to bomb numerous targets in Belgium, England,