UESPA, Space Central and other Starfleet aliases.

[Mr. Laser Beam]

^ Alpha Centauri is the fifth founding member of the Federation, but I don't know what area of expertise its sub-fleet (if it had one) could possibly be responsible for. You'll have to ask @Christopher about that one.

Although whatever sub-fleet that might be, the Defiant (NCC-1764) was probably part of it, as its crew (as shown in "In A Mirror, Darkly") wore an insignia that was different from all four of the other sub-fleets I mentioned. Again, though, I don't know what area of Starfleet this could possibly refer to. Maybe @Christopher's saving that for a future novel.

 

[Timo]

My preferred interpretations, point by point:

Star Service ("The Conscience of the King"): Kirk uses it to uniquely identify "his" Kevin Riley among the no doubt millions of Kevin Rileys in the universe and the tens of thousands in Starfleet, so odds actually are that it refers to something far more specific than Starfleet. I thus feel we should assume that Kevin Riley was decorated for his stellar service with the rare Star Service medal, making him uniquely identifiable.

Spacefleet Command ("The Squire of Gothos"): Slip of the tongue; our heroes speak of spaceships instead of starships now and then, too.

United Earth Space Probe Agency ("Charlie X" and "Tomorrow Is Yesterday"): A distinct organization akin to NOAA, in direct charge of the Antares but not of the Enterprise in "Charlie X", and being given the use of the Starfleet vessel Enterprise (or at least some star hours aboard her) in "Tomorrow is Yesterday".

Space Central ("Miri"): Not an organization or an operating authority at all, but a specific facility. Vulcan has its own Space Central in "Amok Time", so this might be the traffic control facility for a given area of space (there being no need to specify the facility beyond "the" in the context of the episode, because no other Space Centrals were responsible for that area of space. OTOH, Space Central is providing "teachers" and "advisers", but apparently also some sort of an improvement over the mere "medical team" that Kirk laments. Quite possibly a central hospital or comparable relief facility, then?

Timo Saloniemi

 

[Spock's Barber]

I'm glad they more or less settled on using Starfleet Command because it just sounds cool as it rolls off your tongue.

 

[johnnybear]

Tell me about the dispersal of your United Earth Space Probes!
JB

 

[johnnybear]

Go climb a perennial plant with an elongated stem or trunk!
JB