Do you want spaceships with artificial gravity like those in Stars Wars or Star Trek or would you prefer the retaining section of 2001 or Babylon 5? How about speed and interstellar travel? Are you happy with the pulse fission warp engine that allows you to travel faster than light or do you want ships to travel using known physics and chemistry? Weapons are a classic issue with most films littered with blue plasma bolts and lasers flashing between spaceships. Again the author needs to make a choice between the visual and the story whilst fitting in plausible scientific explanations.
All of these questions came to the front with my Star Crusades series. The first book was supposed to be more of a Full Metal Jacket in space type story, with little thought on the concerns of spacecraft and politics. As with all projects though, the plan changed and here I am with three books completed and a detailed world with colonies, ships, factions and strife already made. What about the science though and what decisions did I make?
With regards to weapons, well, I wanted modern weapons brought to their most advanced iterations. Soldiers use rifles but with advanced ammunition, better optics and integrated command and communications gear. All of this exists but it work better and more efficiently. Ships use rail guns, weapons that we have already started to get working though they are far from ready. The problems of power and heat being issues I can deal with assuming better power and engineering system in the future. Movement, distances and travel are another issue and for this I have elected to not use FTL to speed up events. Ships take time and even with my advanced technology they still take almost a year to travel between Alpha Centauri and Proxima Centauri. Rotating sections are used when ships are coasting, long distances where ships accelerate are able to create levels of gravity based on their own increasing velocity.
I think the issues of science in science fiction are always at the forefront of the writer’s mind and it is important to remember that we make the decisions in our stories to create a certain feel and style as much as create a sense of realism. In the end the battles of Star Trek and Star Wars are epic and exciting even though we know you can’t see the beams, there is no fake gravity and that parsecs are not a measure of time!