[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.