Introduction to Planetary Science

the urge to explore 5
not catch on, he did explain the motions of the
planets in their orbits around the Sun and thereby
provided the foundation for modern astronomy.
However, two centuries passed before the people
of the world were ready to think about space
travel again.
The science fiction novels of Jules Verne
(1828–1905) and later those of H. G. Wells
(1866–1946) generated interest in space travel and
inspired some of the pioneers whose scientific
contributions have made the exploration of the
solar system a reality. In addition, the paintings of
Chesley Bonestell, Ron Miller, W. K. Hartmann,
Pamela Lee, and other space artists have let us see
places in the solar system and in the Milky Way
galaxy we have not yet been able to reach. Chesley
Bonestell’s images, which appeared in numerous
books, magazine articles and movies starting in the
early 1940s, inspired an entire generation of future
explorers of the solar system including Wernher
von Braun, Arthur C. Clarke, Carl Sagan, Fred
Whipple, and Neil Armstrong (Miller and Durant,
2001; Hartmann et al., 1984; Miller and Hartmann,
2005). The individuals to be considered here
include Konstantin E. Tsiolkovsky (1857–1935),
Robert H. Goddard (1882–1945), and Wernher
von Braun (1912–1977).
Konstantin Eduardovitch Tsiolkovsky
(Figure 1.2) became interested in space travel
as a young man after reading novels by Jules
Verne (e.g., De la Terre à la Lune; From the
Earth to the Moon, published in 1865). In
1880 Tsiolkovsky took a job as a mathematics
teacher in Borovsk, Kaluga Province of Russia,
where he began to think seriously about how
humans could live in space. In 1892 he moved
to the town of Kaluga where he designed
liquid-fueled, steerable rockets, and spacecraft
that included gyroscopes for attitude control and
airlocks through which astronauts could exit for
extra-vehicular activity (EVA) in free space. He
also designed an orbiting space station which
contained a greenhouse to provide food and
oxygen for the occupants. These plans were
included in a scientific paper which Tsiolkovsky
wrote in 1903: “Investigations of space by
means of rockets”.
Tsiolkovsky was convinced that humans
would eventually colonize the solar system and
then move on to planets orbiting other stars in
the Milky Way galaxy:
Figure 1.2. Konstantin Eduardovitch Tsiolkovsky (1857–
1935) was a Russian rocket scientist and pioneer of
cosmonautics
“Men are weak now, and yet they transform the Earth’s
surface. In millions of years their might will increase to the
extent that they will change the surface of the Earth, its
oceans, the atmosphere, and themselves. They will control
the climate and the Solar System just as they control the
Earth. They will travel beyond the limits of our planetary
system; they will reach other Suns and use their fresh
energy instead of the energy of their dying luminary.” (i.e.,
our Sun).
Although Tsiolkovsky did not actually build
rockets or spacecraft, he influenced many young
Russian engineers including Sergey Korolev who
later became the “Chief Designer” of the Soviet
space program. Korolev led the team of engineers
that designed and built the rockets that launched
Sputniks 1 and 2 in 1957 and which put Yuri
Gagarin in orbit around the Earth in 1961.
.
Robert Hutchings Goddard (Figure 1.3), like
Tsiolkovsky, became interested in space flight
as a young man after reading the science fiction
novel: “War of the Worlds” by H.G. Wells. He
studied physics at Clark University in Worcester,
Massachusetts, and received his doctorate in
1908. Subsequently, he joined the faculty of
Clark University and started to experiment with