I've been meaning to do a proper survey of this little detail for years. Alas, this is not such a survey, but I wanted to publish
something on it anyway.
I mentioned it to Mike Okuda on Twitter back in 2012 regarding the claim of "more realistic" flamey explosions in space that they were adding to TNG in the remaster, in the hopes that they'd work to preserve the original effects.
(Ugh . . . lemme just interject here to say: People, flaming space explosions are
not more realistic. They're pretty, in their own way ... even pretty awesome-looking at times:
But it is just weird to think that there's enough air for big orange flame. A small hull breach with fire shooting out into the vacuum, dissipating rapidly? Sure, go for it. But a ship blowing up into a liquid fire that maintains its shape is just goofy.
Even in an atmosphere, fire in zero-g doesn't act like that. I complained more about this
here . . . and newer pic references for that post are
here.)
Past space explosions were much more realistic, inasmuch as being shown as rapidly dissipating clouds of vapor and particles. ILM has invariably excelled at blowing up Oberth Class ships in a most beautiful way, be it in Star Trek III or the first regular episode of TNG. Here's the Grissom going up:
The above explosion is good, very good. (So good, in fact, that they reused it for the destruction of the Enterprise-D stardrive section in
Generations.) While the thumbnail might make it difficult to see the Grissom, it was fantastic on the big screen.
But in the TNG era, the special effects of explosions of space objects including starships were generally somewhat smaller, framed for smaller screens . . . that means the ships were bigger (and thus visible) in the initial blast, and the cloud comparatively smaller. With the ship so visible, then, they needed a way to
disappear the model effectively. Simply having some of it vanish wouldn't do. So, the solution they apparently came up with was to
spin the exploding ship. I call this the
spinblast.
From a production standpoint, this served to make the model seem to disappear without just having it fade as might happen in a transporter effect, and it meant they could use explosion effects that weren't configured just so in order to hide the disappearing ship parts.
From a tech analysis standpoint, thought, it also means the explosions were profoundly energetic. The acceleration involved in achieving super-quick rotation of a vessel or station massing hundreds of thousands of tonnes in the space of a frame or three is no mean feat.
Here are a few smaller vessel examples. First, from "The Defector"[TNG3]. The first explosion frame is just overlaid effects, but the second explosion frame shows the ship rotated something like 60 to 75 degrees from its prior orientation, and the ship disappears:
The below two examples are from "The Die is Cast"[DSN3] . . . the sequence shows two Jem'Hadar bugs squashed by the Defiant. Both show a violent, sudden rotation upon their destruction, measuring three and two frames, respectively, before they're invisible:
Given that the vessels are already basically blowing up at these points, it would be peculiar to conclude that the spin alone was sufficient to disassemble them. However, it would be fair to say that there is undoubtedly some high-velocity debris being slung from the vessels. And, in the case of the first bug above, we can observe that the port and starboard nacelles were still attached to the central thorax at the time of spinning.
Now, we need to consider a few things. I'll work up the math later, but I just want to put the proverbial bug in your ear, here.
See, that first bug is pretty obviously hit in the nose area, so it isn't like the ship spun laterally because of a hit to an outer area (from our perspective) like a nacelle. Instead, the rotation was caused by something else. Perhaps the ship's forward weapon emplacement blew sideways, or perhaps the ship's drive systems malfunctioned spectacularly, or perhaps the vessel's mass-lightening field failed in a particular fashion, et cetera.
(Bear in mind, however, that when a space station such as the one from "A Matter of Perspective" blew, it had a spinblast as well . . . stations are not generally thought of as running with mass-lightening fields, so that is probably an invalid idea.)
Whatever causes the rotation, the simple fact is that in the case of the first bug the only obvious sources would be internal/external explosion with a lateral bent (like a car's radiator blowing out to one side), or engine malfunction. In the case of a Jem'Hadar bug, this involves a very significant bit of energy. Recall that at 95 meters long, a battlebug is in the range of 30,000 to 120,000 tonnes, or thereabouts. Even the smaller figure would require a remarkable amount of energy to cause it to snap around at such brisk clip.
Of course, the argument could be made that mass lightening would ease the load, there, but this presumes an explosion of mass-lightened ship parts could affect the mass-lightened ship differently . . . or in other words, it assumes the explosion energy is not lightened, for some reason.
Whatever the case, it's an interesting effect. Keep an eye out for it in non-CGI TNG-era episodes and you'll see it quite a bit.
