Mars and the remarkable Viking results

It is pointed out that the Viking missions to Mars are the most extraordinary and complex remote effort ever performed by man. Factors which made the Viking results so remarkable are related to the technological engineering accomplishment, the voluminous scientific data about the planet, and the public interest. Quite surprisingly it was found that the Viking 1 landing site was very similar to the California desert. Attention is given to details of spacecraft landing on the Martian surface, aspects of landing site selection, the design and the operation of Lander instruments, the nine different investigations performed by the Lander, the significance of the pictures obtained of Mars, the remarkable heterogeneity of the planet, the extent and variety of volcanism, the presence of water in the solid and gaseous form on the Martian surface, the presence of water in the liquid phase at some time in the past, the two natural Martian satellites, the composition of the Martian polar caps and their changes during the seasons, the composition of the atmosphere, and the biological results, which remain ambiguous.