Whereas the previous Surveyor missions were undertaken to examine mare surfaces as potential landing areas for the Apollo Program, the primary objective of the Surveyor VII mission, based on purely scientific motivations, was to explore a contrasting highland region and, specifically, to determine the chemistry of the highland material for comparison with the Surveyor V and VI chemical analyses at the mare sites. Site selection was limited to some extent by Surveyor operational constraints, but primarily by the requirements of 10-m-resolution photographs from the Lunar Orbiter Program for landing site certification. None of the nine sites studied in detail appeared capable of providing an unambiguous answer to the highland chemistry. The final selection of a site to the north of Tycho was based on the belief that the youthful character of the structure implied a minimum of contamination to the surface layers by foreign material via meteoritic processes. Moreover, the selection of a site near the rim of a major lunar crater promised insight into the “microscale” properties of a structure that represents the dominant morphologic feature on the moon.
