Martian landscape seen from Viking 1, 1976.
© National Aeronautics & Space Administration / Science & Society
This shows a flat rock-strewn surface with a pink sky. Two Viking spacecraft were launched towards Mars in 1975, each carrying a lander spacecraft and an orbiter. Both succesfully landed their probes on Mars to study the Martian environment, soil constituents and to search for simple life forms - none were found. Viking 1 was launched on 20th August 1975 and landed in the Chryse Planitia region of Mars on 20th July 1976. It continued to return data to Earth until November 1982.