THE LUNAR ORBITER 1 MISSION

Mission Description

Launch:  10 August 1966
Imaged Moon:  18–29 August 1966
Apollo landing site survey mission

During its 35-day mission, Lunar Orbiter 1 collected an enormous quantity of data on the topography of the lunar surface. A total of 413 high- and moderate-resolution photographs were taken. This included 262,000 square kilometers of the nearside of the Moon and over 3,000,000 square kilometers of the farside. All the primary photo sites were photographed as planned, except for sites I–4, I–6, and I–8.1. The orbiter also obtained environmental data during all periods of visibility and from the cumulative effect of periods of occultation. In addition, over 1000 station hours of tracking data were obtained. These were used to further define the lunar gravitational field.

Selection of the Target Sites

A set of ground rules was established to guide and direct selection of appropriate targets sites. Among the objectives were (1) to obtain samples of significant terrain types, (2) to concentrate on the most promising areas within the Apollo zone, and (3) to examine promising Surveyor sites. The results of the Ranger 7,8, and 9 missions contributed a great deal of supporting data. Surface roughness was of primary concern from the standpoint of landing requirements for the Apollo missions. Possible information of scientific value, as well as of direct value to the Apollo mission, was also considered in the selection of target sites. A total of 10 sites were chosen for this mission.