[dotancohen]

1. You are correct it's not very far.

2. "Not far" is the difference between "land humans on the surface of the moon and return them safely to Earth" and not doing that. Some of this stuff was unbelievably lucky, go read about the F1 engine baffles - getting that right was pure stupid luck as much as it was engineered.

And there were literally hundreds of these examples - across five different space vehicles and the interfaces between them.

[marshray]

Yes, it's absolutely a lot of work, cost, and risk to design and qualify a new rocket for human spaceflight from scratch. Especially if you've let all your institutional knowledge drift away in the meantime.

I just don't think that comes close to meeting the bar of "lost technology" in the sense that term is used by the extraterrestrial pyramid theorists (i.e., the manipulation of fundamental physical forces allowing the blocks to be levitated into place).

[dotancohen]

I agree with you about that. We are facing an engineering challenge, not a physics challenge.