The energy to build the system comes from the partial assembled system, plus some initial bootstrap energy. It grows exponentially. We seem to have enough today to build small factories in orbit.
The manufacturing scale comes from designing factory factories. They aren't that far in the future. Most factory machinery is made in factories which could be entirely automated, so you just need some robots to install machines into factories.
The energy to build the system comes from the partial assembled system, plus some initial bootstrap energy. It grows exponentially. We seem to have enough today to build small factories in orbit.
The manufacturing scale comes from designing factory factories. They aren't that far in the future. Most factory machinery is made in factories which could be entirely automated, so you just need some robots to install machines into factories.