Broadly speaking, spacecraft fall into two technological categories. There are the sublightspeed variety that we are very familiar with, such as the Space Shuttle (okay so the bit we call the “Shuttle” is actually the “Orbiter”). Then there’s the supralightspeed variety which don’t yet exist, the USS Enterprise and Battlestar Galactic springing to mind as examples there.
Some novels use the technology we have today and go for gritty realism, others jump into the more distant future, get rid of all the lightspeed limitations which can cramp a good story, and head off into Star Trek territory.
Even Star Trek acknowledges the transition between the two technology levels in First Contact. They presented a world where the transition was a break-through and everything changed at that point.
I seem to be unusual in that I have written science fiction novels which often span the transition period, assuming it will be a tricky process with no single, universe-changing breakthrough. In Astronomicon: Icarus, the titular vessel uses a plasma drive allowing it to reach small fractions of the speed of light, but never get close to a “warp capability”.
The salvage vessel in the same novel, the EUSS Wagner, travels out to the Trojan Cluster using a plasma pulse drive. This is very much a transitional technology which is obviously purely a temporary stage in development. While it is drastically faster than the mining vessel Icarus, is incapable of breaking the light barrier.
The third vessel in Icarus is the mysterious “USS Oppenheimer”, a highly classified experimental vessel fitted with, what the crew call, a “Torus” drive. Details of the technology are mostly kept secret by the remnants of the vessel’s crew but we are given the basic concept of how its space-bending main drive functions, allowing it to bypass the limitations of the speed-of-light.
Of course such technological leaps can be perilous, as the crew of the Oppenheimer have discovered. The first attempt to bend space on an interstellar scale does not go to plan, forming the exciting basis for the whole novel.
I plan to write more books that sit within the transition time of such technology. In real life things often don’t work properly, especially with new technology and I think it can be fascinating to explore that in science fiction too.