What percentage of NASA's Apollo program is considered to be open source as of today? I mean if I wanted to replicate a lunar mission from scratch exactly the same way they did it, regardless of the cost, would I be able to build the rockets and spacecrafts, do the astronaut training etc. just using publicly available sources?
How many technical drawings are there available for the hardware? There are numerous Apollo rockets and spacecrafts including engines in various (mostly public) museums which may allow for inspection to clarify details missing in the documentation. Regarding software at least the Apollo Guidance Computer seems to have been open sourced on GitHub.
The open source consists of both open source hardware and open source software. Let us try to evaluate the level of open source telling that HW is 50% and SW is 50%. Like this, a fully open sourced hardware and half open sourced software project would rate 75% overall. The subsystems should be evaluated on an importance scale, so if a mission has 5 critical subsystems (power, thermal, navigation, comms, etc.) then each should roughly have a score of 20%.