While everyone is speculating about "realistic" space games and weapon mechanics, I really just think about steampunk all the time
It's pretty much that, projecting current technology unchanged into the future. A bit like the 60 year old thought, that computers would soon be twice as fast and only four times as big, making it feasable to have one or two per nation for whatever....
Whomever is actually interested in some real world "magitech", should look for Warp drive theory after Alcubierre and Van den Broeck (You might have heard of it, the thing that fries everything in front of it with a giant radiation wave when slowing down
).
It was just recategorized from unrealistic to theoretically possible in the last symposium of the 100 year starship initiative. Happened last month.
It's a NASA/DARPA funded Project, so no need to worry about the credibility of the whole thing.
Whomever is interested in that project, here's a link
http://100yss.org/(Disclaimer: The Drive is a theoretical possibility, the 100yss a partly governmental funded project with no guarantee to bring you to vega in your lifetime
)