A couple of designs I made for transportation in space.
First off a rotating tube. While reading about real design issues on the dsign of space transportation I got the image of Rama and the whale probe from Star Trek in mind.
So, needing rotation to simulate gravity it had to be circular. To provide surface area it either had to be too large or long so it became a tube. The passengers live in the wall which is several floor thick.
Engines are placed in the centre on both ends and along the tube to provide thrust and manouverability.
The inner portion of the tube contains heat exchangers, fuel containers and whatever’s needed.
Size is variable depending on the number of people on it and the rotation speed for gravity.
Second, what TV tropes calls a “big dumb object“. It’s a improbable world ship with each cube roughly the size of Earth. Providing power and gravity are micro suns located at the centre of each cube. Each set of eight cubes are connected by circular wall sections a third on the inside.
This world came from the Borg cube (I love the simplicity) combined with the manga Blame!. I wanted to provide characters with a huge world for diversity and exploration and have a simple cool design.
This world would just travel through space and harvest asteroids and lifeless planets with automatic drones to provide itself with materials.