These notes came out of my attempts to make vector-based starship combat in Classic Traveller easier to grasp. I’ve played the game off and on since I first bought it in 1981, but starship combat as-written has never figured heavily, and when I have played it, I mostly just stuck to lasers (since book 2 doesn’t really explain how to play with missiles).

I returned to Classic Traveller during the pandemic, and (inspired by the “Traveller out of the Box” blog) decided to run a game using just books 1-3, with the rules as written. That series of blog posts also turned me on to the missile rules in Special Supplement 3, at which point everything just clicked. For the purpose of this blog entry, I’m going to be dealing exclusively with Classic Traveller books 1-3 (in their 1981 form), with the Special Supplement 3 missile rules.

One of the problems I’ve always had with book 2 starship combat is the use of different units throughout it. There are light seconds, kilometers, scale mms, and different things are given in different units. Because of all the craziness with different units, I went through and converted things to the same units:

• 1 light second ~= 300,000 km ~= 3000mm

• 0.5 light second ~= 150,000 km ~= 1500mm

• 2 light second ~= 600,000 km ~= 6000mm

• 100 km = 1 mm

• 100D for a size 8 world = 1,280,000 km, ~4 ls

Distances

Having everything in one table starts to make things clear. Book 2 space combat takes place at enormous ranges, and the weapons used retain their accuracy to a huge distance. Take a look, especially, at the point at which lasers first get a negative DM: 0.833 light seconds. A pirate who is clever then can achieve the starship version of surprise and hit their target from a point farther out than their target can even see them. The rules don’t say what would happen at this point, but in my game I rule that this counts as detection, so the target can fire back.

Now lets look at missile flight time. Missiles are enormously effective, with the typical missile accelerating at 5-G for six 1000 second turns. Special Supplement 3 gives rules for creating all sorts of different missiles, and so I created a bunch of different ones (ranging from a 5G 2 turn missile with a huge warhead to a 5G 10 turn missile that isn’t great against military targets but can fly for a long time).

Missile travel time (turns)

One thing that surprised me is how long it takes for missiles to travel to their target at long ranges. If a poor, beleaguered Free Trader is attacked by a pirate from 0.8 light seconds away, it would take 3 turns for the missiles it launches to hit the pirate.

What I love about this is that it makes player choices more clear: Do you mount missiles, which can do heavy damage to a target while risking being shot down, or do you mount lasers, which do less damage, but do damage immediately?

Adding to this is the fact that most of the missiles in Traveller are self-guided, so they will track their target even if the firing ship is destroyed. This means that even if the pirate takes out that Free Trader, the missiles the Free Trader launches would still be coming. Pirates need to be careful who they choose as their prey…

Computers

Civilian ships typically don’t spend on their computers. Ditto software. Auto-evade is cheap and small and easy, and gives a nice -2 to being hit. Typically, target and launch are the limits to what is available, offensively. Auto-evade and (occasionally) anti-missile defensively.

Military ships tend to have large computers, and the cost of software systems is small compared to the rest of the ship, so they spend. Maneuver/evade-4, 5, or 6 are common, along with ECM, anti-missile, and return-fire on the defensive. Offensively, the predict software is common, ditto gunner, multi-target, and select.

Paramilitary ships tend to fall one way or the other. Things like a scout courier is probably armed and equipped like a civilian ship, while a Type T patrol cruiser is set up like a military ship.

Fighters

Fighters come with a model/1 computer, which gives them better options than other armed small craft, but it still doesn’t give them the ability to run a ton of software, so they end up looking a lot like (very fragile) civilian ships. This means that fighters are easy targets in military combat, but they can deploy defensively and cut power, making themselves invisible to military ships past 1 light second.

As defensive craft, I could see large numbers of fighters, each armed with triple missile racks, forming a screen around valuable targets. As offensive craft, they would probably simply rely on numbers to overwhelm their targets, launching their full complement of missiles as fast as they can and then breaking off. They end up being less “space fighters”, and more of attack craft. 10 fighters, each carrying triple missile launchers, costs less than MCr 200, and can easily overwhelm a 400 ton Type T or SDB.

Tactics

Finally, the good stuff! On player scale, starship combat is extremely chancy. While something like a Type T has the computer to support a lot of combat software and the toughness to take a few hits to the engines, the more typical Type S or Type A doesn’t. Those ships will not have an easy time hitting their target, while a lucky hit can easily leave them completely dead in the water. This makes combat feel like a desperate gamble for them, which really suits the small-ship Dumarest-style feel of the game.

If you are playing a pirate, you will want to be careful to choose your targets. Take advantage of your sensor range to attack while your target can’t see you. Make use of lasers to try to disable your target in the first turn, and then demand their surrender. If I were playing a pirate, I would probably eschew missile launchers, since there’s too much of a chance of destroying the booty I want to capture.

On the other hand, players in ships like the Type-S or Type-A should probably select their weapons more for their deterrence. A single hit on a pirate ship could cost them millions of credits, while a turret full of missile launchers could potentially destroy them. Remember: You don’t have to be able to defeat a pirate, you merely have to be a harder target than the other ships.