These sci-fi spaceships may be fictional, but their designs are rooted in real scientific principles. From the modular ...

"There's no realistic time frame at all for such a thing ... Casey Dreier, chief of space policy at the Planetary Society, ...

and I'll try to use my experience as a former director of space operations at SpaceX and current professor at University of Southern California, USC, and give you a rating on how realistic it is.