Looks like two boxy pontoons joined at the middle by a transverse block on top of which is the palace tower, with all the windows and lights. And the great big arches, at least one and apparently two, connecting the bottoms of the pontoons. And a free-floating miniature star held in the middle of the arch - in this picture we only see its glare reflected from the insides of the arches, but another angle (with Burnham's shuttle) reveals the star itself.
Might be a Vulcan-style ring drive. Might be a Romulan-style drive where it's important to have a compact astronomical object in the middle. Might be a Cochrane drive, with the pontoons being the two nacelles, and the rest just gaudy decoration or perhaps fancy weapons.
Is this an ancient vessel, dating back to the early days of the Empire and relying heavily on technology stolen from the Vulcans that Cochrane gunned down? Or a modern juggernaut? Is she built to outgun everything else in the 2250s MU by a ridiculous margin just because? Or is she a mostly harmless barge with a few token torpedo launchers and a need for escort?
Here's hoping the next episode will offer lots of techno-fun, against this week's almost techno-devoid take. (Oh, we did get some 'babble on the spores, but that was pretty much it.)
Is the shuttle new, too? Or at least modified to MU specs? I don't think I have seen those cheek fairings with the three glowing dots (guns?) before...
Timo Saloniemi