Comment by hdgvhicv

Massive implications from that

A magic unobtainium drive which works in a consistent way is fine, just call it “hyperspace” or whatever

There’s a difference between hard sci-fi and soft sci-fi, but they are both still sci-fi, you can tell optimistic stories of the future with a “battle drive”, as long as you keep it consistent. If the drive cancels relativity effects and allows travel at 5000c that’s fine. Just ensure you travel at 5000c, no hoping across the galaxy in a few days, but travelling to another star in a few days or even hours is fine.