DESTINATION MOON: A History of the Lunar Orbiter Program
 
 
CHAPTER X: MISSIONS IV AND V: THE LUNAR SURFACE EXPLORED
 
 
 
[269] The first three missions essentially satisfied the Apollo requirements for photographic data of potential landing sites. This opened the two remaining missions to other work. Photography could concentrate on specific areas of the Moon which scientists from various disciplines wished to explore more closely. It could also enable NASA cartographers to compile a much more nearly complete lunar atlas than any then in existence.