The link I referenced stated that care was taken to ensure the tolerances required were achievable by 19th century technology. The biggest difficulty was in ref

The link I referenced stated that care was taken to ensure the tolerances required were achievable by 19th century technology. The biggest difficulty was in refining the designs into actionable manufacturing plans. Of course they used CNC; why mess up at the last step. For both moon landing and quantum computing the challenges were recognized to be enormous, but achievable by unthrottling the money faucet. Cold fusion is different because there is not even a theoretical venue ahead. It would be a true search in the dark at this point. Yes, I recognize that these astronomical projects were seldom launched with purely scientific goals in mind, and I wish humanity would do it for the science in the future.