In terms of actually produced sets, the largest LEGO Classic Space ships are things like the 928 Galaxy Explorer and the 6985 Cosmic Fleet Voyager.
These were large sets, to be sure. If they had had all the greebles and decorative pieces of modern sets, they’d probably be in the 800+ piece range. But in absolute terms, they’re pretty paltry things, and there’s no way that they can be the largest ships the Classic Space Federation possesses.
We know this from the fact that 90% of the ground vehicles sold in Classic Space sets will in no way fit into the cargo bay of an LL928 Galaxy Explorer.
The Federation might build some of their planetary vehicles on-site, but I doubt this is the case for all of them, so they have at least one transport ship that’s bigger than Galaxy Explorer, and they ought to have a whole series of transorbital ships that aren’t designed to be able to land. Big galactic cruisers with crews in the hundreds or thousands of minifigures. Giant carriers with hangar bays for multiple 924- and 928-class ships.
The generic names of these ships are a bit of a puzzle. Sets 928 and 924 both got called “Space Cruiser” in different parts of the world, and that’s about the most non-militaristic-sounding “big ship”-type name I can come up with. Given The LEGO Group’s feelings about warlike toys, it seems improbable that the big ships of the Galactic Federation are “battlecruisers” or “destroyers” or “dreadnoughts”.
I’m proposing a modification of “space cruiser”. Since the “Space Cruiser” is designed for transatmospheric work and planetary landings, a larger ship designed for transorbital operations without landing might perhaps be a “Hyperspace Cruiser”.
I think it works. “Hyper-Cruiser”, “Hyper-Carrier”, “Hyper-Transport”, even perhaps “Hyper-Frigate”.
All this to say “I was in the mood to build a Classic Space ship large enough to have a proper furnished interior”.
As “big” ships go, this is pretty small; something of a hybrid between the big transorbital ships I’m envisaging and the smaller transatmospheric ships we have sets of. I envisage it as a fast hyperspace transport, able to get small amounts of personnel and material across the galaxy quickly. It has a small crew complement and is able to be handled by a sole crewmember if need be, as well as an interior furnished as something other than solely a flight deck and a smallish cargo hold.
The flight deck is in the forward cockpit; this “Hyper-Courier” is more on a scale at which the lovely big curved windscreen piece makes visual sense as a cockpit than the little mining vehicle where I used it before (though that worked).
Behind this is a section containing sleep pods, which I’m seeing as a kind of general-purpose device that can function in multiple modes for general sleep or medical stasis, or for personal hygiene as a shower/cleaning chamber. The ship has three, though two more could be fitted further aft.
Behind this is a recreation/mess area with tables and chairs, which can be turned to multiple angles to facilitate conversation. A Space Fleet officer in a red uniform is talking to someone in civilian dress.
Behind this is a general-purpose space with a domed roof; this would be configurable for multiple uses depending on the ship’s mission. Currently mostly empty, it might be used to store mission gear, or hold more sleep pods, or whatever.
Directly behind this is the cargo hold. Larger than that of a 928 Galaxy Explorer, it is still not a big cargo volume, and given the ship’s courier role would generally be employed for small amounts of time-sensitive or particularly valuable cargo.
On either side of this, the Hyper-Courier has airlocks. Actual, functioning airlocks that mean that the passengers and crew don’t need to weap spacesuits in the interior. The 24th Century version of OSHA probably requires flight crew to be suited while on duty in a ship of this size, but technically the interior space is pressurised, as it ought to be.
Each airlock has a space for astronaut airtanks and a hook upon which to hang a helmet. Because of the vagaries of LDD, I’ve included the airtanks but not the helmets. They have an interior door (full height) and an exterior hatch (smaller). I have abandoned the design I used on the Orion Transport, both because it was overly complex without actually fully working, and because the design wouldn’t fit in this Hyper-Courier.