Nichelle Nichols was slated to star as Uhura, but as the part was rather small, Ms. Nichols turned the part down. Structure, logic, function, control. A structure cannot stand without a foundation.
Logic is the foundation of function.
Function is the essence of control. I am in control. I am in control. The nebula is a standard class-17 nebula. Tuvok had his first Starfleet mission when he was 29, and left the same year.