This. The author points out the 54F00, seemingly distracted by the 54'00 part and similarities in TTL glue logic layout that the F part is completely dismissed without acknowledging that these chips had sub-4ns edge rates and were indeed fast while remaining compatible with older TTL families. Throw in high SMD density on a multi-layer controlled-impedance PCB designed to survive brutal operating environments when PCs and CAD were still in their infancy...even today, it's humbling to contemplate just how much work would have been required to qualify such a design.
> But it's interesting that the Shuttle was still using TTL...
These systems had super long lifecycles and were required to be extremely reliable. I'd be surprised if the contractor that was responsible for the design would have been allowed to integrate any IC that wasn't listed in a QML.