Viking
NASA's Viking program sent the Viking 1 and 2 landers to Mars in August, 1975. Viking 1 landed on July 20, 1976, with Viking 2 following a few weeks later
This ground-breaking program generated impressive new technologies, but, the heart of the mission was about science. It's goal was to learn and discover, And discover it did. The Viking program missions returned to Earth 55,000 images of the Martian surface from orbit, another 55,000 images from the surface of the Red Planet, details about the planet's atmosphere and composition.
Construction of the Viking spacecraft was done primarily by the private company Martin Marietta (now Lockheed Martin). The team worked for six years to build the ground-breaking spacecraft.
Viking 1 Titan launch
Viking 1, atop a Titan/Centaur rocket, launched from Complex 41 at Cape Canaveral Air Force Station on August 20, 1975. The half-billion mile journey took 11 months. The spacecraft came into orbit around Mars in mid-1976.