[9] As a major part of America's first lunar exploration effort NASA initiated the Surveyor Program in may 1960 with a dual objective: to build an unmanned lunar lander for, surface investigations and to build a lunar orbiter for photographic coverage of the Moon, with instrumentation to explore and measure some of its environmental characteristics. Both would use the Atlas-Centaur launch vehicle. NASA charged JPL with the responsibility for carrying out the objectives of the Surveyor Program. JPL employed a conceptual philosophy for Surveyor which reflected the thinking of the Office of Space Sciences and which was similar to that of Ranger: design and build a common spacecraft bus to carry out different missions.1
On March 23, 1961.,the Lunar Sciences Subcommittee of OSS recommended that an orbiter have the capability to: 1) achieve high-resolution photography which could define objects smaller than 10 meters in size, 2) obtain total photographic coverage of the limb area and of the far side of the Moon at a resolution of 1 kilometer, [10] 3) take reconnaissance photographs of the lunar surface at 100 meters resolution, and, finally, 4) make stereo pairs of areas where high-resolution photography was planned.2
The idea of modifying the Surveyor Lander system to serve as an orbiter was very attractive to NASA Headquarters planners, but during the last quarter of 1961 the Office of Space Sciences began to review the feasibility of a Centaur-class orbiter in the weight range of 950 to 1,100 kilograms. On December 5 Charles P. Sonett, Chief of Lunar and Planetary Sciences at NASA Headquarters, requested his staff scientist Newton W. Cunningham to compile an inventory of JPL's programs and a description of their status. 3 Specifically he wanted to know the stage of development of he authorized Surveyor Orbiter.
Early in January 1962 Cunningham sent a report to Sonett detailing the activities which JPL had been conducting since 1958 pertaining to a lunar orbital mission. These amounted to the following: 1) a 1958 study on close photography of the Moon with a spacecraft launched by the Jupiter Rocket, 2) the development of a unique camera system for Pioneer IV, 3) a study on 1959 for the Vega Program concerning instrumentation for a lunar probe in [11] which a dual vidicon camera was to be used for obtaining low-and high-resolution photographs of the Moon4, and, finally, 4) a study made in 1960 of a lunar orbiter experiment.5
Cunningham also pointed out in his report that JPL scientists could not successfully adapt the Ranger photographic system for use in the Surveyor spacecraft and that no photographic system had been developed specifically for the long-life requirements of an orbiter mission. This was the general status of the Surveyor Orbiter at the beginning of 1962,
The advent of the Apollo Program soon changed the requirements for a lunar orbiter and placed urgent demands on the Office of Space Sciences for information on lunar surface conditions. Apollo needed these data in order to design hardware and missions, and in turning to the Office of Space Sciences the Office of Manned Space Flight helped to reshape the philosophy supporting the need for a lunar orbiter spacecraft.