Let's take some of the stock footage of the TOS Enterprise orbiting a planet. You all are aware, aren't you, were such a scene photographed in real life, that the ship would not appear to travel in a curved path, right? What I mean by this is that the ship often looks like it's a model a few feet long that's circling a beach ball a few feet in diameter that's sitting only a few feet away from it. I regard this as a trope intended to help the viewer realize that the ship is circling the planet.
On the other hand, this would
be an accurate portrayal of the ship flying a figure-eight orbit above the spot of interest on the planet down below.
And the ship would probably be quite interested in doing that very thing, as its phasers and transporters both seem to suffer from limitations in operating beyond the planet's horizon. Transporters struggle to penetrate even a couple of kilometers of rock; phasers are even worse.
A powered orbit in figure eight shape would also nicely explain why ships that lose engine power are often in danger of falling down to the planet below.
(Then again, in "Mirror, Mirror" the evil starship is interested in intimidating a local center of political power on the planet down below - yet is established to be on an orbit that takes her away from the optimal firing position from time to time! This would certainly be a good time to do a powered orbit above the region of interest.)
A more interesting thing about those "orbiting" scenes IMHO is that most ships maintain an attitude of portside-to-planet, in fact carefully avoiding the pointing of "dorsal" or "ventral" or "bow" sensors towards the most interesting target in the vicinity. ST3:TSfS offers some rare shots of the ships flying with their bellies towards the planet, while DS9 and ENT did a lot of shots where the ship's dorsal side points to the planet (which in turn is located on the upper part of the screen, so the ship is still "the right side up" but the setup carries an impression of defying gravity).
If the topside of the saucer of the TOS Enterprise
is part of a sensor system with four orifices, it should worry us a bit that the topside is never
pointed at anything interesting when the camera dwells on the ship. Never
. Of course, it may be that the sensor is actually omnidirectional (or downward-oriented), and the four glowy things aren't orifices for incoming information but merely exhausts for glowing emissions associated with the functioning of the instrument. Still, the fact that only three of them glow properly is somewhat counterindicative of a single four-element instrument...
Could the lighted ring actually be complete around the saucer and we only saw 3 segments lit up at any one time?
Who knows? Some of the windows on the ship are established to be shuttered normally ("Mark of Gideon"); if all the shutters were opened, perhaps the ship would be a veritable Christmas ornament of nearly unbroken lit surfaces, some of which would be windows while others would be sensor orifices for instruments more refined than our eyes.
It's just a bit curious that all the portholes we do
see open and glowing are always the same ones. If there are others, seamlessly closed (much like the torpedo tube muzzles, supposedly!), why are they always