[logi_cal869]

The only means of monitoring the early flight of a space craft launched from Diego Garcia, therefore, is from ships.

BS, obviously.

Thus the larger question - presuming that the prospect of the US having built a moon base in the mid to late 70s is true - is therefore,

How did we build a base without rockets and why are the Russians, Chinese etc being silent on the matter, since they obviously know exactly what's going on???

[GreyFriar]

Actually, the US Army did research and draft a proposal to establish a base on the moon. In 1959 a feasibility study was begun under the name of “Project Horizon” to “establish a lunar outpost.” It was declassified in 1961. And it was NEVER built.

I recommend reading Dr. Fred Borch’s article posted by the Army Historical Association:

https://armyhistory.org/soldiers-moon-armys-strange-true-plan-lunar-outpost/

or with some of the illustrations here: https://www.defensemedianetwork.com/stories/an-army-base-on-the-moon/

The declassified study is available on the US Army Center of Military History website via free downloadable pdf: https://history.army.mil/faq/horizon/Horizon_V1.pdf