[44] However, the RFP was to state clearly that under no circumstances would these secondary objectives be allowed to dilute the major photo-reconnaissance mission. For this reason the Statement of Work which was to accompany the RFP was not to give any detailed descriptions of the secondary objectives.
In outlining the photographic requirements which the RFP was to make explicit, NASA Headquarters counseled Langley to use the following guidelines for identifying cones and slopes on the lunar surface. Cones were assumed to be circular features at right angles to a flat surface. These could be considered as recognized if the standard deviation of the cone's estimated height caused by system noise in the spacecraft was less than 1/5 of the cone's height. Slopes were assumed to be circular areas inclined with respect to the plane perpendicular to local gravity. Again a slope would be considered as recognized if the standard deviation of estimated slope caused by system noise was less than 1/5 of the slope. 58 These criteria required at least two photographic modes in the orbiter to obtain the data: 1) high resolution of limited areas and 2) wide coverage at medium resolution. Any bidder's [45] proposal had to meet this requirement. However, a proposal would not have to employ both modes of photography on any one mission.
The Request for Proposals had also to state clearly that a bidder would provide in his proposal for instrumentation and telemetry capable of measuring certain characteristics of the lunar environment. These components would have to function independently of the photographic subsystem in order to record data regardless of the success or failure in obtaining pictures. Among the various environmental conditions which might be measured, micrometeoroid flux and total exposure to energetic particles and gamma radiation were two whose measurement would be necessary for gauging the performance of the spacecraft while also providing vital data for the Apollo Program.
In addition to this instrumentation the bidder would have to be able to determine precisely the altitude of his spacecraft at the time of each photographic exposure, the orientation of the picture in relation to lunar north, and the relative angle of the Sun to the portion of the Moon's surface covered by any photograph. The bidder would have to demonstrate his capability for providing such data as would be necessary to position all points within an area of contiguous coverage while being able to pinpoint 90% of all well-defined points to within 100 meters of their true horizontal positions relative to each other in the [46] high-resolution mode. Finally the RFP was to require each bidder to be able to give the locations of photographed areas within one kilometer of their correct positions in the lunar system.59
Headquarters defined what it desired that the RFP do on the basis of the STL and Bellcomm studies, with the results of the two Scherer groups' research. Thus the spin-stabilized spacecraft system was preferable to Headquarters, but the RFF, in final form, did not precisely state which kind of spacecraft system would best do the job.
By August 1 Langley was concluding its preparations on the RFP. It also had drawn up the Statement of Work (SOW) document to accompany the RFP when it was released. The SOW set forth explicit guidelines for each bidder to use in developing a proposal. In addition to a general description of the mission which Lunar Orbiter would perform, the document stated the requirements which the spacecraft system would have to fulfill, the testing procedures and the interfaces which the contractor would have to establish and carry out, and the division of tasks which the contractor would have to perform. 60