|From NASA: "Taken by the Viking 1 lander shortly after it touched down on Mars, this image is the first photograph ever taken from the surface of Mars. It was taken on July 20, 1976." Image Credit: NASA|
I can’t speak for others, but for me, the Viking program had the biggest cultural impact on how I viewed planetary spaceflight. While the Viking landers weren’t able to rove beyond their landing sites, and couldn’t take cool “selfies” upon the Martian surface, the images from school science books and the January 1977 issue of National Geographic forever made an impact on my mind: something from Earth had made it to a neighboring planet, landed successfully, and made its home there permanently. Along with the two Voyagers and ESA’s Giotto, the Vikings fired my imagination, making it seem as if the Solar System was wholly explorable.“Time and time again I repeat, ‘It’s incredible.’ And it truly is. Nothing before or after can compare. It is transparent, brilliant, boundless. An explorer would understand. We have stood on the surface of Mars.” - The late Thomas A. “Tim” Mutch, leader of the Viking Lander Imaging Team, discussing his reaction upon seeing Viking 1’s first image
And of course, in the last few decades, countless spacecraft have proven science fiction to be science fact. More recently, spacecraft such as ESA’s Rosetta and NASA’s New Horizons have conducted surveys of two seemingly impossible-to-reach worlds (respectively, Comet 67P and Pluto).
An excellent 1978 NASA publication, The Martian Landscape, written largely by Tim Mutch, discussed Viking’s origins. Mutch stated that the Viking mission was defined by NASA in 1968, but it had a predecessor possessing a name that would become familiar to space buffs much later.
Then Mutch drops one of the most superbadass sentences in spaceflight history: “Each of these Voyager missions was to be launched by a giant Saturn V rocket. Successive missions were to contain increasingly sophisticated scientific equipment, culminating in a 90- to 450-kg biological laboratory in the 1977 Voyager spacecraft.” Can you imagine ambitious Mars missions lofted by the mighty Saturn V? That would be almost too cool to endure.
2. Mutch, T. (1978). The Martian Landscape. Washington, D.C.: NASA Scientific and Technical Information Office.
3. Gore, R. (1977, January). Sifting for Life in the Sands of Mars. National Geographic, 151(1), 3-31.