The initial exploration of Mars - Rationale for a return mission to Chryse Planitia and the Viking 1 Lander

A discussion of the concepts behind planning a landing site on Mars is presented. On the basis of the engineering constraints and the scientific objectives which are likely to be imposed on the first few missions to the surface, reasons for supporting a return to Chryse Planitia and the Viking 1 landing site are given. Samples from the Hesperian ridged plains would be useful in establishing an absolute age for the present crater chronology, and samples of soils from the vicinity of the Viking 1 lander would be useful in determining the significance of the results from the Viking biological experiments. Soil samples would provide consistency between unmanned and manned missions, may contain fossil microorganisms, and could be useful in determining the mechanism responsible for outflow channel formation.