Viking rover studies

Intensive study of Mariner 9 data has resulted in an understanding--although far from complete--of the geologic processes affecting the Martian surface and of its history of development. The results are briefly summarized in the following section. The second section consists of geologic studies of four widely separated areas on Mars (figure 1) selected to provide as wide a variety of environments as possible. For each area a detailed geologic map of a high resolution Mariner 9 B-frame was made and several exemplary traverses were plotted to show how the various geologic units might be visited, sampled, and analyzed. In each area 5 to 10 geologic units appear to be accessible. A substantial fraction of each area is covered by loess-like or dune-like units or channel deposits. That is, there are extensive deposits of transported debris that may be strongly sorted by sedimentational processes. However a variety of indigenous rocks are also present in each of the areas selected. Volcanic rocks of several types and impact debris occur locally. These are masked to varying degrees by the transported debris.

Two additional capabilities are necessary beyond those available for Viking '75. The first is a decrease in the size of the landing ellipse so the spacecraft can be put down close to a desirable landing point. The second is a mobility system to allow exploration in the vicinity of the landing point in order to sample the various units locally present more effectively.