Wow, just getting started on here, so I've got some catching up to do. Awesome story and really does capture the TOS feel. I can even hear the music while I'm reading. One miniscule quibble that may be moot anyway, standard Navy tradition is to address officers by their core rank... meaning Lieutenant Junior Grades are addressed as Lieutenant, Lieutenant Commanders are addressed as Commander, etc. I think that any example I noticed that Starfleet followed this generally, but not positive.
But that one part didn't take away from the story one bit. Eagerly looking forward to more.