Voyager:A
Journey of Exploration and Discovery 
There are strikiing similarties-and
equally string difference between the voyage of exploration in the sixteenth
and seventeenth centuries and the programs of planetary exploration of
the past 30years.
Columbus,Magellan,Vespucci,Drake,and others set sail from Europe 500 years
ago to destinations about which they knew little.But they were determined
to explore,and so they went.
Over the past three decades, the National Aeronautics
and space Administration(NASA) has launched
a series of robotic explorers-Mariner,Viking,Pioneer,Voyager;Glileo,Magellan,and
Mars observer-to seven of the eight other planets of the solar
system.Unlike the earlier voyages of exploration, we
began ours with the knowledge gained frrom several centuries of observations
ofthe planets with ground-based telescopes.Even so,the frist close-up images
and measurement of the surfaces,
atmospheres,ring,moons,and magnetospheres proved to be
just as surprising to us as the flora,fauna ,and inhabitants of the New
World were to the European captains and crews hundreds of years ago.
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