Encyclopedia of the Solar System 2nd ed

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CHAPTER 46


Planetary Exploration


Missions


James D. Burke


The Planetary Society
Pasadena, California


  1. Introduction 5. Venus 9. Small Bodies

  2. Program Evolution 6. Earth 10. Outer Planets and Moons

  3. Sun and Heliosphere 7. Moon 11. Conclusion

  4. Mercury 8. Mars


1. Introduction

Immediately upon launchingSputnikin 1957, it was clear
that technical and political conditions would soon permit
humans to realize a dream of centuries—exploring the
Moon and planets. With large military rockets plus ad-
vanced radio techniques and the dawning skills of robotics,
it would be possible eventually to send spacecraft through-
out the solar system.
At first, however, the effort mostly failed. Driven by Cold
War desires to show superiority in both military and civil en-
deavor, the Soviet and US governments sponsored hectic
attempts to penetrate deep space, using strategic-weapon
boosters, cobbled-together upper rocket stages and hastily
prepared robotic messengers. In time, as the equipment
became more reliable and the management more capable,
successes came—but in-flight failures have continued for
decades to afflict all deep space programs. Lunar and plan-
etary exploration is barely achievable even with the finest
skills.
Here, where our purpose is to trace the development of
flight missions, we do not dwell on the failures. The accom-
panying tables list only those missions that yielded some
data in accord with their objectives.
In the early years, the Soviet Union garnered all of the
main firsts: the first escape from Earth’s gravity, the first man


and first woman in orbit, the first lunar impact, the first lunar
landing and the first lunar orbit. But the US program came
from behind and scored the first data from a planet, Venus,
and ultimately the grand prize, the first human exploration
of the Moon.
Though Cold War rivalry provided emotional stimulus
and government support, both programs were scientific
right from the start. The earliest satellites were launched in
support of the International Geophysical Year. Every mis-
sion carried some instruments to elucidate the character of
its target body or region, and this largely continued as more
nations and agencies joined the program. As a result, there
is now a huge body of data, some of it still unexamined,
from flight missions complementing an important archive
of ground-based and Earth-orbiting telescopic observations
of the Moon, planets, and small bodies in the solar system.
In what follows, mission results will be briefly mentioned,
with cross references to more extended treatments in other
chapters.
Exploration of the Sun’s domain by robots and at the
Moon by humans has now placed us in a position to build
strong hypotheses about the origin and evolution of the solar
system and also to begin the study of other such systems as
they are discovered. The missions that made this possible
are an unprecedented expression, on a grand international
scale, of peaceful human values and achievement.

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