First feasible time to colonize the moon

Question

The first man on the moon was there on July 20th, 1969. After December of 1972, there has not been a person on the moon since. But, what if the missions to the moon had kept on going? By what time could we reasonably had a permanent habitat there. A quick search turns up a lot of questions that say that we could have had a moon base by now, given that the economic need was there. What if the cooperation between the Soviet Union and the United States on space flight hadn't happened? Surely the next step after a man on the moon would've included some sort of habitat there?

I'm not talking about full-scale cities and the likes, but a simple habitat like the one used in the The Martian movie. So basically a couple of modules/pods that are connected together to make an expandable habitat. And before anyone asks, no, I'm not intending to have my characters plant potatoes on the moon.

Eventually it would grow from the research habitat described above to a more permanent settlement there. There needs to be something to get there that's hard to get elsewhere. It might be Helium-3 for fusion purposes, or as a hub for space travel (go from Earth to the moon, then board a larger ship and continue on towards Mars, Venus or the outer planets).

Answer 1

One of the original plans had the Apollo missions create a moonbase core for full time 12 person occupation in 1980; though even that wasn't the first plans as there was Project Horizon and Lunex. Clearly if the desire and perceived necessity was there then the first permanently occupied lunar base could have happened with Apollo 11. Once it was decided that the direct and overt militarization of space wasn't the goal (so no setting off nukes to study the moon/impress people) then 1980 was the stated goal for a permanent presence on the moon.

Now it should be noted that colonization is rather different than having a permanent presence on the moon. The permanent presence would be similar to having a permanent presence in Antarctica or the international space station. To actually colonize the moon the problems of living in the micro-gravity of the moon (even to the point of knowing what those problems are in the short and long term) would need to be answered.

Answer 2

Building a habitat probably could have been done pretty early on, say the mid 1970s. The technology is not that different to what you need just to get there, just larger in scale.

The REAL problem though, is maintainance. Moon dust is notorious for getting in everything and being massively abrasive. To this day it isn't clear if we have seals which could deal with it long term.

Lunar dust is charged, so it tends to be electrostatically attracted to everthing. It isn't weathered, so it's sharp and wears out anything it sticks to... which is everything. Breathing it in is incredibly hazardous.

So you'd need positive pressure airlocks and probably charged sacrificial dust attractors. Both certainly seem doable with 1970s technology, but who can say for sure? We still don't really have a way of dealing with it, but then again we haven't really tried.