What I mean by a waste of space is if you fill in the gaps between the engines and the rest of the ship for example.

Empty space can serve purposes too.

Empty space can serve purposes too.

yeah the vacuum of space is not exactly helpful or useful to the crew. Since it is outside the ship. Go look at the map of the Farstar. Note all the space that is outside the ship that would be far more useful if you filled it in and made it usable space.

It possible that some of that space is useful as a dump for heat sinks or just as a planned gap to prevent certain interference from the engine outputs.

uh huh....because they haven't managed to deal with that in other ships that do not have those gaps...

Empty space can serve purposes too.

Like fuel?