- [Voiceover] Coinciding
with America's Bicentennial the Viking spacecraft would be launched on a journey to Mars in search of answers. The program called for four spacecraft, two to orbit the planet and
two to land on the surface. The Viking program was the largest, most intensive planetary expedition NASA had ever embarked upon. Preparations for the mission demanded years of research and development and the efforts of
thousands of individuals. Viking's primary mission: search for life. On earlier missions, the mariners unveiled the barren surface of Mars, extinguishing ideas of highly civilized communities living on the planet. However, the mariners were
above the surface, not on it. Was there something being left unseen? We could get closer and
with better cameras. It was time for another look. On August twentieth nineteen seventy five, a titan centaur launched
Viking one into space on a mission to mars. About two weeks later,
Viking two followed its path to the red planet. For almost a year, the world waited. Of all the planets in our solar system, Mars and Earth are the most similar. For this reason, many scientists feel that learning about Mars
is absolutely necessary in order to better
understand our planet, Earth. They call it comparative planetology. The Viking mission was
to them a sort of quest for the holy grail. A mission of extreme importance. The pursuit of long searched for highly speculative historical evidence. While the Vikings travel
to their destination over million miles away, the
world buzzed with excitement, anticipating their arrival. This was, after all, a new
frontier about to be discovered. Now it was no longer just
the talk of science fiction. A spacecraft was about to
land on another planet. On June nineteenth, nineteen seventy six Viking one arrived at the planet Mars and immediately began
sending back photographs. One hundred and thirty four thousand bits of information
arrived every second. Viking's first lander touched
down on Chryse Planitia on July twentieth, one month later. Viking two joined them on August seventh and its lander targeted
for Eutopia Planitia landed on September third. For the next six years, the
Viking mission would take over fifty five thousand photographs sending to Earth images of volcanoes, dust storms, evolving polar regions, and immense canyons. Evidence of lake beds, stream channels, and lava planes painted a
picture of a very different Mars from a time long ago. The landers performed a
multitude of experiments, biological and chemical, day after day for over three martian years, digging, retrieving, and analyzing. And yet not one trace of
organic material was found. And so, many who held great expectations for the discovery of life on Mars were let down, left disappointed. However, for each question that the Viking mission answered, there was a new question born. Questions so tantalizing
that soon after we received Viking's final
message in November of nineteen eighty two, scientists anxiously began planning a return trip to the red planet. (wind blowing) (upbeat music) - [Jon] Hello and welcome
to Kennedy Space Center. NASA's home for launching humans--