Discovering MarsMuch of our current knowledge of Mars is the result of investigations conducted by a fleet of spacecraft starting with the Mariners in the mid-1960's. The 1971 Mariner 9 mission which looked at the entire planet instead of just the southern hemisphere, as was the case with the earlier missions, reveals huge volcanic mountains and discloses surface erosion and dried riverbeds. This pamphlet gives a chronology of the United States and Russian spacecraft that have examined Mars along with a short description of each mission. Photos of the Martian surface are included along with descriptions of the topography of the planet. The reverse side of the pamphlet contains a large photo of the Martian surface which clearly depicts the Vallis Marineris, a gigantic rift valley extending a distance equivalent to that from New York to Los Angeles.