The Viking Mission was assigned to NASA Langley Research Center after an in depth selection process by NASA Headquarters. This was in no small part due to the individuals that later became the Project Office, as well as the Center resources. Because the mission entailed launch vehicles, orbiters, and landers, there were many NASA Centers competing for the Project Office assignment, including Jet Propulsion Laboratories. However, there was one (of many) unique factors that made the Langley RC the prime choice, and that was the individuals from the Lunar Orbiter Mission who succesfully planned and executed five unmanned lunar orbiter missions to help select the Apollo landing sites by mapping the Moon's surface. The success and resulting expertise in site selection and mission planning was a critical factor in their assignment. In addition, the expertise in mapping the surface and developing sequences for the imaging system onboard, were a direct transference to the Viking mission. This document by Norman Crabill and Wilbur Mayo covers details of the Lunar Orbiter Mission design, and is a lens through which the planning for Viking can be seen. Both Crabill and Mayo continued with the Viking mission bringing their expertise and experience.