Image credit: Lockheed
Image source: Mike Acs
Lockheed’s Extended Lunar Operations was an extensive lunar base development program that would (after Ranger, Surveyor, and Apollo) have begun with the delivery of ELO modules by Saturn C-5s in 1969, an interim lunar exploratory base constructed in mid 1971 and a permanent base complete by 1975.
Image credit: Lockheed
Image source: Mike Acs