My first Blender project

I am still learning how to use Blender, I don't know that I will ever get it to the point of printing my first project but it would be cool if I do. From what I gather I still need to figure out how to close all my shapes that have open areas, and connect all the shapes before it can be printed. I am sure there are other things that need done too that will keep me from ever printing it.

Its a spaceship with gravity domes for (Passenger,Animal,Plant comfort) during its voyage.
It has gravity both while Accelerating or (Coasting,Orbiting) due to its dual orientated position domes.
I don't know if in a print the gravity domes could really move but it would be cool. Some sort of hinge would need to be added, along with the dome support leafs moving along too and that's way beyond my abilities.

LINK: It is a Spaceship model with gravity and living domes. Blender file at Google Drive

Play with it if you want. If your able to fix its printing issues let me know. I would love to see it printed.

A good bit of the answer depends upon how large you want to make the item.
If you keep the planet and the ring, then the spaceship will disappear because it's so small.

If you remove the planet, ring, and moon, keeping only the spaceship, the support posts have too small of a diameter, and the logo is going to disappear.

Then, the tiny antenna on the top, and the engine nozzles are not "closed", the big end of each cone is open, and you will need to fix that.
The base platform above the engine nozzles needs to be thicker. and the top antenna is too small.

Next to last, the engine nozzles will break off during cleaning - this is a common issue for codes attached to larger surfaces - it shears off at the connection. Making the nozzles a bit larger and using fillets may help.

Last, some of the things above can be fixed simply by increasing the size of the item (say 2x larger), but once you do that, you may wish to make the whole model hollow so as to bring down the cost.

I have no intent on including the backdrop planet and the sun for that matter.... Woah!!

Looks like I really have my work cut for me if is to ever be printed. Now I at least I have an idea of its weak printability points. While some points sound easy to adjust...(ie. resizing), I will have to figure out how to close objects and to make them hollow(I had thought they already were). I still need to learn how to connect the objects as well. Guess its time to try to figure out to implement some of the changes. Thank you much for your useful critique.