On this day 40 years ago, our Viking 1 lander touched down on the surface of Mars – the first successful landing on the Red Planet, paving the way for future missions. The Viking 1 and 2 missions to Mars , each consisting of an orbiter and a lander, became the first space probes to obtain high resolution images of the Martian surface; characterize the structure and composition of the atmosphere and surface; and conduct on-the-spot biological tests for life on another planet.
For more information: http://www.nasa.gov/viking
