How do you know how an entirely alien species will decide how to build their ships?
I don't know how they'll build their ships. However, let's look at it again.
Fact: The distance a ship can travel from any inhabited planet can be expressed as follows:
Distance = Speed of ship * time until a non-replaceable part breaks on said ship.
Yes, with superior engineering techniques, these can be increased. However, the limit of these is as follows:
Max Distance = Almost Speed of Light * Lifespan of crew (with the exception of colony ships or cryogenic ships)
So, without Faster Than Light travel, you hit a limit:
And we traveled faster and further spreading in our galaxy and before long we could see the day when our reachable systems would have been exploited. And then there would be nowhere else to go.
However, if you do use FTL travel, you have a much higher limit on your speed variable:
And we discovered subspace. It gave us our galaxy and it gave us the universe. And we saw other advanced life. And we subdued it or we crushed it. In months the extermination of billions of years of evolution on a similar but slower path. With subspace our empire would surely know no boundaries.
Any species intelligent enough to discover Subspace will realize that any equation that uses the speed of the ship as a variable is actually dependent on the MAX speed of the ship. So any species that is intelligent enough to discover subspace is intelligent enough to realize that this is a very important addition to every ship.
THE REST OF THIS POST ASSUMES THAT THE SPECIES IN QUESTION HAS OVERWHELMINGLY DECIDED TO ADOPT SUBSPACE TRAVEL.
Now that you've got a subspace engine on your ship, you have to decide where the power is going to come from. a subspace drive requires a certain amount of power, depending on how you built it. That power comes from somewhere. You put a larger engine on there. This means more energy. So you can now travel subspace, fly at 1200 m/s, and still power your shields and weapons.
Ignoring the size of the power generator, there is still a problem with it. If you have enough energy to power all of that, you're flying a bomb.
Energy needed = x + y * z * (a / b)
x = (min energy for shields, guns, subspace drive, etc.)
y = (distance ship can fly before a refill)
z = (mass of ship)
a = (velocity of ship)
b = (time it takes to accelerate to that velocity)
let's assume that x and z have been perfectly optimized. You can't get them to be any smaller, no matter what you do.
y can be changed around, but remember that you'll still need it at a fairly high amount to do any real traveling (or dogfighting)
so the important variables are a and b. Yes, you can easily get a ship to use very little energy and still travel very fast. It just has to take forever to get to that speed.
Assuming you want acceleration high enough that you can do a dogfight, your equation has been simplified to:
Energy needed is proportional to max sublight velocityif you're going at 85 m/s, great. You don't need much energy. However, if you want to go at 850 m/s, you need ten times the energy. and there's where we hit our problem:
Any energy that can be released in a controlled manner can be released in an uncontrolled manner.I'm assuming everyone remembers the Shivan Comm Nodes? Imagine if every ship in a dogfight behaved like that when it died.
That is why they don't go faster.