I was looking through the effects ini of Winterous' orbital weapons trying to figure out how it's done, and here's where I'm puzzled:
It works by launching an explosive which gibs or explodes an emitter 800 pixels in the air, I got that, but the emitter it gibs emits another emitter which emits the main thing which is particles.

So why doesn't it just use one emitter?
This isn't just about the orbital weapons but I've seen other mods which do this.

It probably has to do with the way in which things are aligned. For instance: my Shock Mortar launches an emitter which spins around. The idea is for this emitter to constantly fire downwards as it flies. But since it spins, the shots would go in all different directions. To counteract this, it instead emits another short-lived invisible emitter (and note that anything that is spawned or emitted starts off straight up-and-down), which THEN fires stuff downward.

I'm not 100% certain about how the orbital weapon works, but my hunch is that the issue is similar.

I think it's for better accuracy. Both emitters emit at 90' (straight up), but I think that might be 90' from the object's current rotation. So, an emitter that's gibbed has a random rotation and 90' is somewhere to the left or right of where abstract 90' is. The emitted emitter, however, is not rotated, so its' 90' is abstract 90' which is what you want.
Correct me if I'm wrong...
EDIT: Half-ninja'd by Darlos.

Ok then, I thought it was that I just thought that it would work a different way.
Thanks, end thread.