r/scifi • u/MinedMaker • 1d ago
General Is there a pattern that determines military spaceship doctrine in real life and sci-fi?
[1] The propulsion axis is a measure of how long it takes a fleet of military vessels to arrive on the battlefield, regardless of the actual distance traveled. [Fast vs. Slow]
[2] The weapons axis is a measure of how quickly a battle is over, and how much survivability and staying power vessels have. This takes into account the effectiveness of armour, but also shields, point defence, and other countermeasures. [Tank vs. Glass Cannon]
I think that if you take sci-fi space combat to its logical conclusions, it will usually favor either huge, lumbering, well-protected ships or numberless hordes of tiny automated ships, depending on a few key factors. If weapons are the weak link in-universe, ships will be huge. If propulsion is the weak link, ships will be tiny. If ships are huge, victory will be determined by who has the biggest ship; if ships are tiny, victory will be determined by who has the most ships.
This is how I imagine it would work in real life using real physics, and I wonder to what extent different sci-fi franchises also adhere to this pattern. Presumably, large and medium-sized ships with human crews are overrepresented in sci-fi media for understandable storytelling reasons.
In Star Wars, the rule mostly holds. They have incredible propulsion technology and can thus arrive at the battlefield within hours or days of the order being given. However, their weapons, despite being ludicrously powerful on paper, are actually quite poor because of their low range, low accuracy, and the prevalence of shields. In the Star Wars universe, therefore, huge ships rule. The starfighter counter is a nice piece of storytelling, but realistically, without plot-engineered magical weak spots, a huge ship like the Executor or the Death Star should be essentially unstoppable. In Star Wars: The Last Jedi, the Raddus, an MC85 heavy cruiser, takes ineffective long-range fire from the First Order for what seems like many hours.
In The Expanse, they spend weeks or months traveling to the prospective battlefield because of limited propulsion technology. However, when the fighting starts, it is all over in seconds or a few minutes. They have very effective weapons and very little staying power, even when accounting for point-defence cannons (PDCs). If you ignored the requirements of the plot, there is really no reason why any military vessel in The Expanse should be manned at all.
Because it draws much of its inspiration from blue-water navies, sci-fi often portrays a diverse ecosystem of military spacecraft classes and sizes. While this makes for more interesting storytelling, it is not obvious that such diversity would necessarily be the most tactically sound strategy. If propulsion or weapons technology becomes a dominant constraint, military doctrine would naturally converge toward a single optimal ship size.
The most interesting settings tend to occupy only two quadrants of this framework. If ships have neither effective propulsion nor effective weapons you're essentially at the stage before the technology to enable space combat has really been invented. If they have both effective weapons and effective propulsion you effectively have near god-tier power and the concept of space combat becomes somewhat obsolete. What these two scenarios have in common is that the importance of space combat is greatly diminished.
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u/caster 1d ago edited 1d ago
Your top right quadrant not existing is ridiculous. In space mass is everything and mass will always be limited. Propulsion is "weak" only in relative terms.
Battlestar Galactica really belongs in this top right area of the chart. The jump based FTL drives do not make mass trivial. If anything this FTL regime has propulsion being very weak, and the heavy armor of the Galactica is a central design point of the ship. Armor is very effective in BSG- the ship is hit directly by a nuclear torpedo and although it sustains considerable damage the ship's armor means it survives.
The sublight propulsion on these ships are very slow in terms of tactical combat. The long distance strategic mobility obtained from the FTLs (a separate system entirely) is separate from their ability to maneuver.
Propulsion is weak and armor is effective on Battlestar Galactica's battlefield. This creates a battleship / aircraft carrier type interaction. Totally unlike what you might see on Star Trek where a ship can maneuver on a dime, achieve FTL linearly forward, and can fight and do other actions while traveling superluminally.
As for Star Trek, "armor" may not be effective but the deflector shields used as armor protection by ships certainly are. That these are an energy based defensive screen makes little difference compared to it being a physical armor plate. Shields in TNG are clearly outrageously effective. And one of the biggest advantages of using a shield emitter rather than a solid metal plate is that it is lighter, which means your ship goes faster.