The Emblem of Starfleet Command
The Starfleet Command seal consists of a dark blue circle with a silver Starfleet arrowhead in the center. The Command star is cut out from the arrowhead, so we can see two bright dots through this "hole". Many more dots (stars) surround the arrowhead. The text on the upper edge of the circle reads "Starfleet Command", on the lower edge it is "United Federation of Planets". Two large dots separate these two blocks of text. A yellow flight path (or comet tail) runs from the left behind the arrowhead in a curve to the front and ends at the right dot between the two text blocks. This feature is similar to the NASA logo. An outer and an inner red ring border the text area, which itself is black.
The Starfleet Command emblem never appeared on TNG and was created by Michael Okuda as late as for the fourth season of DS9. It is prominent in several DS9 and Voyager episodes.
In the Star Trek Sticker Book, on the cover of which the logo of Starfleet Command is shown at a large size, Mike Okuda writes:
"The Starfleet Command seal was first seen 'Homefront' (DS9) and later in 'In the Flesh' (VGR), although the agency itself, of course, dates back to the original Star Trek series. The symbol was intended to be somewhat reminiscent of the NASA emblem."
Even after a thorough review we could not find the logo either in "Homefront" or in "Paradise Lost".
Mike Okuda: "I don't recall where it appeared in 'Homefront'."
The actual first appearance seems to be a bit later in the fourth season of DS9, in "Rules of Engagement". In this and many other episodes we can see the logo on a yellow flag. It turns out, however, that there are two variants of this yellow flag. In later episodes, a gray flag with a differently colored logo should be added. Finally, we can see the emblem as a standalone seal in several episodes.
Variations of the Starfleet Command logo would later be created for Enterprise and for Discovery.
DS9: Rules of Engagement
In this episode we can see the logo for the first time, in the center of a yellow flag. Next to this flag we can also see the blue Federation flag. The arrowhead in the center of the flag is silver, and the logo corresponds exactly to the description above.
DS9: Behind the Lines
After a long time we see the logo again in this episode, for the first time on the back of a PADD. The PADD contains an "Intelligence report" on a Dominion sensor array in the Argolis Cluster discovered by Starfleet Intelligence. As the information is classified, the words "For Eyes Only" are written on the front of the PADD, across a Starfleet logo. On the back of the same PADD we can see the Starfleet Command logo. It looks exactly as described above and as depicted on the cover of the Star Trek Sticker Book. The arrowhead has a gray gradient that is intended to mimic the metallic effect of silver.
It is important to note that in "Behind the Lines", Admiral Ross appears with Starfleet's new admiral uniform for the first time. However, in this episode it still lacks the belt buckle with the Starfleet Command logo surrounded by olive leaves. Here, Admiral Ross's uniform has a simple, rectangular belt buckle.
In the same episode we also see the yellow flag of Starfleet Command for the second time, both in Admiral Ross's office and in Sisko's office on Starbase 375. In all other episodes featuring Starbase scenes, as well as in all subsequent DS9 episodes, the yellow flag will never resurface, however.
DS9: Favor the Bold
This episode is the first to show the belt buckle of the new Admiral's uniform. Both Admiral Coburn's and Admiral Ross's uniforms clearly have this belt buckle. As mentioned above, it is an interesting mix of the Starfleet and the Federation logo, as the Starfleet Command logo is surrounded by the olive leaves of the Federation logo. This belt buckle would appear in several more episodes.
At least one of the belt buckles was listed for auction by It's a Wrap! in 2007.
VOY: In the Flesh
Although it is just a fake scenario created by Species 8472, "In the Flesh" has the first appearance of the emblem on Voyager. We can see it behind the bar in the Quantum Café. In terms of color, there are slight differences. The arrowhead is white or light gray. The red rings seem to be missing or are very thin. The area between the rings is no longer black, but light gray. The text inside the rings is no longer white, but black. The comet tail retains its yellow color.
In addition, Boothby's office has several windows with the logo. These windows were reused in later episodes in Admiral Paris's and Admiral Janeway's offices. For these later appearances, however, frosted instead of clear glass was used. In the variant of the logo on glass, the arrowhead, the area between the two rings and the small stars in the background are all silver. The command star and the text are therefore transparent, or later white. The yellow tail, however, is still colored.
Star Trek Insurrection
In this movie we see Admiral Dougherty wearing the admiral's uniform and the decorated belt buckle described above.
DS9: The Changing Face of Evil
Here we can see the logo in a flower bed on the grounds of Starfleet Headquarters. The logo looks like it was described in the introductory text, the two red rings are clearly visible.
DS9: The Dogs of War
One last time we see the logo on the back of a PADD in "The Dogs of War". This is probably the same PADD as in "Behind the Lines". The PADD is used when Admiral Ross transfers the command of the USS São Paulo to Captain Sisko. This is a formal Starfleet document, hence probably the Starfleet Command sticker on the back of the PADD.
VOY: One Small Step
In this Voyager episode, the gray version of the Starfleet Command flag shows up for the first time, on the torpedo coffin of Lt. John Kelly at the end of the episode. It is interesting that this new flag was created for the episode, since in previous scenes in which a Starfleet officer was buried in a photon torpedo, the Federation flag was always used. It is also unclear why the existing yellow Starfleet Command flag was not used. Maybe the yellow variant was considered too cheerful for a memorial service, which is why the new, gray flag was made.
The gray flag has two red rings. The text between the rings is white. The area between the two rings, which is black on the yellow flag and on the standalone seal, is gray, like the rest of the flag. Also, the area inside the inner circle, which is dark blue on the yellow flag and the seal, is gray here. This circle is missing the white stars as on all other variations. The arrowhead is silver (it appears to be dark gray in the episode), the Command star is black. Inside the star there are still two white dots that are supposed to represent stars, which is probably an oversight. The comet tail is still yellow, as usual.
Mike Okuda: "Regarding the grey flag for 'One Small Step,' it was likely made because DS9 and VGR had separate set dressing departments, and sometimes it is more convenient to have duplicate props than it is to coordinate with another production that might need it for something else. Or it might simply be that our set decorator, the late Jim Mees, wanted a grey flag, instead of the yellow flag that we used in DS9. On the other hand, I seem to recall that Jim had me make a yellow flag (with a different graphic) for Starfleet Command in Enterprise. I also recall that Jim wanted the United Earth flag in Enterprise to be grey."
The flag was later auctioned by It's a Wrap!. The photo of the prop clearly shows the silver color of the arrowhead and the black command star.
In "Pathfinder", the Starfleet Command emblem appears in several variants and in different places. For the first time, it can be seen in plain gray/white on the façade of the Starfleet Communications Research Center building. All components of the logo, including the stars in the inner circle, are present. This shot was often reused in later episodes that take place on Earth.
Several admirals, including Admiral Paris, can be seen with the decorated belt buckle.
In Admiral Paris's office the gray and the yellow variant of the Starfleet Command flag appear together for the first time. The gray flag is the same that was introduced a few episodes earlier, in "One Small Step".
If we look at the yellow flag, we realize that it is not the same prop as in the two DS9 episodes. A new yellow flag must have been created. On this new version of the yellow flag, the entire background of the inner circle is black, and not dark blue as on the other yellow flag. Also missing are the stars around the arrowhead (just as on the gray version). However, the two dots inside the Command star are present (just as on the gray version). The two red rings are also present, the text is white, the arrowhead is silver and the tail is yellow.
The picture of the flag from the It's a Wrap! auction clearly shows the differences between this flag and the one that appeared on DS9.
Why was a new yellow flag created? Maybe the old one had disappeared after the end of DS9 a few months earlier. This could be another reason why the gray flag was created for "One Small Step". In all subsequent Voyager episodes featuring the Starfleet Command logo, both flags should always be visible.
In Admiral Paris's office we can also see the windows with the Starfleet Command logo, which were probably reused from "In the Flesh". As already mentioned, instead of the previous transparent ones the panes are frosted now. The logo is unchanged compared to "In the Flesh".
Finally, the logo is visible on a glass door at the entrance to the Pathfinder lab. The design matches the logo on the glass in Boothby's office in "In the Flesh", but is not colored. All the areas that were silver or yellow in this logo are tinted glass while the rest of the logo (and the door) is translucent.
VOY: Life Line
This episode briefly shows the gray and yellow Starfleet Command flags in Admiral Hayes's office.
VOY: Inside Man
"Inside Man" is another episode to feature all variations of the logo from "Pathfinder". This includes the logo outside the Communications Research Center building, the one on the windows in Admiral Paris's office, the two flags, the belt buckle and the glass door to the Project Pathfinder Laboratory. The laboratory space looks completely different and the logo on the glass pane is barely recognizable, but it is the same glass door as still in "Pathfinder".
VOY: Author, Author
We can see the logo on the outside of the Communications Research Center building and on the glass front door to the Pathfinder lab. Only the flags do not appear in this episode.
VOY: Friendship One
The gray and the yellow Starfleet Command flags show up in Admiral Hendricks's office.
In the scenes that are set in the year 2404, the logo can be spotted several times. The first time is in a new take of the Starfleet Communication Research Center. Also, the already known shot of the building appears. Admiral Janeway's office displays both flags and the familiar frosted glass version. The glass door of the Pathfinder Project Laboratory also displays the logo. In the final scenes, which take place in the Pathfinder laboratory in the year 2378, the logo can be seen on the belt buckles of several admirals.
The window panes with the emblems were later auctioned off by It's a Wrap!.
In many DS9 episodes we can see an interesting tube-shaped, blue-red document bag with a Starfleet logo. The logo can never be seen up close, but it has a yellow or golden ring. It is not clear if there is text in this ring. Inside the yellow ring is a black area. Centrally located in this area is a silver arrowhead, in the middle of which we can spot the black Command star. The arrowhead partially protrudes into the yellow ring. Further details are not recognizable. Since this logo bears a certain resemblance to the Starfleet Command logo, it is included here. The bag showed up as soon as in the first season DS9 (e.g. in "A Man Alone"), well before the logo was created for the fourth season ("Rules of Engagement").
Thanks to Star Trek Auction Listings, from where we took photos of auctioned items.