the human body will encounter complications in low and zero gravity
ftl will never happen
space stations are a scam that rich tech ceo's promise
mars cannot be terraformed
life is probably unexceptional and we will never make contact with others
you will all die on earth
Bruh??? How big do you want your spacecraft to be??
If you want a comfortable habitat, you basically need a floating city. I think the typical O'Neil cylinder is about 8km in diameter and 32 kms long. For each module. The more advanced designs typically have two of these that are connected with bearings at the ends and rotate in opposite directions. If you build them this large, you can get earth-like gravity on the cylinder walls by rotating the structure at a speed where (most) people don't get motion sickness. This means your crew doesn't have to put up with the lowered bone density and muscle atrophy that you usually get when you stay in a low g or zero g environment for long periods of time.
Building them this large also means you can have enough plants on board to produce oxygen for the crew, you can recycle waste water, grow your own food etc., there can even be small lakes or rivers on the cylinder walls.
That's largely a concept for space stations, but you could also use these for a generation ship.
oh ok i interpreted your comment as saying "just make your mass so hyuge it's a defacto planet!"
Big. Take the biggest thing and make it bigger. Communism is when things are big, the more bigger the more communister it is.