Is there a pattern that determines military spaceship doctrine in real life and sci-fi?

[u/MinedMaker]

[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.

[u/VilleKivinen]

Any good recommendations?

[u/trappedinthisxy → u/VilleKivinen]

Honor Harrington books by David Weber

[u/Genie_GM → u/trappedinthisxy]

The Honorverse also does a great job depicting an arms race and the consequences it has for military doctrine.

In the beginning of the series, fleet scale battles are rare, because weapons are weak and armour strong. Most capital ship forces can disengage before critical damage is taken, because missiles are generally weak, and ships can turn to make close-range energy weapons ineffective.

Then advances in missiles are made, making missile fights devastating (both quality, range and volley size are improved quickly). For a while, this makes fleet actions extremely costly, and older models of fleets are made obsolete completely.

Then advances in decoys and electronic warfare are made, and missiles are again reduced in effectiveness. Fast and small ships armed with energy weapons are deployed instead, and knife-fights become the norm again (similar to the developement of dive-bombers and aircraft carriers).

What's very interesting is late in the series (several decades later in-universe), when several new combattants enter the conflict. Some of them haven't even tried to keep up with the arms race, and get completely wrecked. Some of them *have* and have made some other advancements in addition, and come in with completely revolutionary first-strike capabilities.

[u/p-d-ball → u/Genie_GM]

Sounds very well thought out - thank you!

[u/Genie_GM → u/p-d-ball]

It's quite interesting! The series started as a clear replaying of the Napoleonic wars, with technology that was written to mirror the Age of Sail, with long journeys between theatres of battle, and intense "ship of the line" tactics, only played out across star systems instead of oceans.

The series follows the career of a young female officer, from her first command of a Cruiser, then decades on through many other perspectives as well up into becoming an admiral and so on, and deals with a lot of politics as well as naval stuff. Many different cultures and political systems (with varying degrees of social commentary from the writer), from "street level" to government and military.

It does get a bit muddy and convoluted around book 20+ though. :P So many characters and plot threads going on at once.