looks like the Roci got a major upgrade since season 3.. landing legs, teakettles for landing in atmo, is that a freaking miniature railgun? curious who did the rebuilding since they managed to tick off all three major powers as well as the systems biggest industrial conglomerate last season.
also interesting that the first ship we see in the trailer has a rotational section.. clearly ship designs have adapted to the 'speed limit' of the gate zone. clearly the Nauvoo's role in the first gate incident left some impressions on people.
the scene with Avasarala looking at the display screen has a ship displayed, not a style we've seen in previous seasons that i can tell. the ship carries the name label CIV_Sinon. and a flight path is displayed below the ship wireframe, with the same label and showing a path taking it between earth and the moon, clipping close to earth. can't tell if it is coming or going though.
right after there is a blink and you'll miss it of a small craft, looking rather cobbled together (or perhaps just very utilitarian) dropping off a missile that proceeds to flip over and fly away back along the ships path of travel. i don't think this is the CIV_Sinon from the earlier scene, the shape of the ship doesn't match.
freeze framing the scene with the two ships near the gate later in the trailer, it looks like the foreground ship is MCRN (going by color and what we can see of the shape) while the background one is UNN (going by styling), and also includes a rotational section (on the nose, and apparently retracted and not spinning. which is probably part of its battle stations mode)
also i love the prefab buildings at the one base.. very plausible approach. i would hope though that if we see other worlds with more greenery that the colony sites look a bit more fireflyish with buildings made from locally sourced materials.