WIP Traveller: Alternative Space Combat

Space Energy Weapons (WIP)

1) Energy and range are linked by a square law so if the range is doubled the energy in the beam is reduced to a fourth. So if a beam has a strength of 4  at range 1 then it only has a strength of 1 at range 2

2) So range bands should be a power of 2, say 1, 2, 4, 8 so short = 1, medium = 2, long = 4, very long = 8

3) If minimum penetration is given an arbitrary value of 1 (representing some unspecified amount of energy) then

– a penetration value of 1 at short range requires a minimum initial strength of 1

– a penetration value of 1 at medium range requires a minimum initial strength of 4 (range doubles so strength/4)

– a penetration value of 1 at long range requires a minimum initial strength of 16 (giving a strength of 16 at short range, a strength of 4 at medium range and a strength of 1 at long range)

– a penetration value of 1 at very long range requires a minimum initial strength of 64 (giving a strength of 64 at short range, a strength of 16 at medium range, a strength of 4 at long range and a strength of 1 at very long range)


For scenery say laser weapons are rated in pounders after Dr Yukio Pounder so

– a strength 1 laser is a one pounder

– a strength 2 laser is a two pounder

– a strength 64 laser is a sixty-four pounder



One way to keep it simple is to say a dedicated war ship can have one laser point for each 100 dtons displacement (in reality this would vary by TL) so a 100 dton ship can have 1, a 3200 dton ship can have 32 etc arranged as desired in any combination, for example

100dt ship: 1×1 pounder

200dt ship: 2×1 pounder or 1×2 pounder

1600dt ship: 1×16 pounder or 4×4 pounder or 1×8 pounder and 2×4 pounder etc

12,800 dton ship with 128 total points of energy weapon potential might have

1×64 pounder for very long range

2×16 pounder for long range

4×4 pounder for medium range

4xquad1 pounder for short range point defense (quad = four one pounders in a turret)

total firepower would be

128 at short range

28 at medium range

6 at long range

1 at very long range

Space Combat Thoughts

A youtube video talking about space combat led to…



1) Stealth: stealth in fantasy is generally about getting into close range. Stealth in space would have to be more about being the first to detect the opponent so getting the first shot i.e. all about trying to get a potential alpha strike at long range.

2) skylarking12’s comments were very interesting and the space jousting idea is appealing i.e.

  • both sides have to choose to close distance
  • one way of doing that would be fast passes

Applying this idea to the 18 wheeler analogy used in the video would be something like two armored 18 wheelers charging towards each other down a highway firing away and then blasting a broadside into each other into each other as they pass like ships from the age of sail but at a much faster speed.

The idea of re-jigging the rules of Traveller ship combat to make it broadsides at 6G is appealing as that could potentially be very quick. roll for damage on each pass until one is wrecked or bugs out.


skylarking12’s comments for future reference

I came across your conversation on space combat, applied to RPG playing. If I could, I’d like to make a couple of points, just my own opinion. The model of “two semi trucks in the desert” has some flaws. Thanks to relativistic, “Newtonian” in-system travel, and the 100-diameter limit of jumpspace travel, just as in the Age Of Sail, it boils down to the fact that even with stealth, your ships are seeing and seen, way before they can fight.


Assuming equal fuel reserves, two ships detecting each other at long range could keep evading each other, move for move, indefinitely, or until one ran out of gas. Space Combat HAS to be consensual in Traveller, just by physics.


Due to orbital mechanics, space combat between vessels in classic Traveller can ONLY happen if the two (or more) ships ALL “agree” (in the initiative phase) to “come together”, that is, to adjust vectors to make a fast pass in opposition, flashing by each other like knights on horseback, doing damage in the moments where they are in range, then flashing past and apart in opposite directions… and taking hours or days to reverse course loop back around if they wanted a second pass …


or both could, if the vectors worked out, choose to make their orbits merge in the same overall direction, (“closing the range”). This merging is more like two cars in adjacent lanes, jockeying for position: and tactics like the pilot turning to present minimal aspect, or to bring a spinal mount weapon to bear, make a difference…. so for RPG party purposes, your PC’s *could* have the opportunity to bring skills to bear like pilotage, navigation, engineering, computer, and gunnery skills.
Besides conventional weapons, leaving chunks of “grapeshot” in your wake after you change vectors could mean the other ship flies into them un-knowingly on the fast pass… and that kind of move to drop that payload CAN be made early in the engagement, with a payoff that only happens if the other guy stays on his original course to run into that “surprise”. Even sandcaster sand could be deadly at high relative speeds. So tactics IS a valuable skill for combat.


Space is big enough that you’ll never catch any ship at a distance, that continues to “open the range”. The only exception is fighting over a “fixed” coordinate or corridor in space, like a planet, moon, asteroid or station. There are only a few, calculable (by both sides) vectors that bring you into range and proper approach to these, and those smaller volumes or corridors CAN be held or patrolled; (that’s what SDB’s are for).


Because you always enter realspace at least 100 diameters out, the planet or moon is ALWAYS going to see you first, hours or days off, before you’re in weapons range. The only way around this is versus planets to conduct orbital bombardment with ordnance dropped from ‘way outside their defense perimeter, hoping they can’t detect the incoming rocks or rods.


When you have to get in close to skim fuel or die, or to make a bombardment run or a pickup, that’s when you’re more or less committed to fighting; you can’t jump out of close orbit, so you commit to the orbital combat dance, like two squirrels, chasing around a tree trunk. There again, player tactics, pilotage, gunnery, all can make a difference. You could choose to approach the planet in the same rotational direction as the enemy, working to “merge”


or you could enter retrograde orbit on approach, and have possible multiple “fast pass” flash, one-shot encounters every 40 minutes or so, with the very deadly head-on-impact speeds this creates. At a station, you could slow down and stand off in a “relative” standstill, and fire continuously, but you also make yourself an easy target that way and usually stations can hold bigger or longer-ranged weapons than ships, so that tactic would be more rare versus flashing by on a fast pass.


So, to finish my wall of text dump, in my play sessions, I already establish if there is even a remote chance that vectors of the opposing ships could be made to merge. (cont).


If the players are spoiling for a space battle, they have to come up with a way to make the merge happen first. This is the gut check/initiative check we roll for first. If that’s a go, I have them lay out their strategy: a fast pass or a merge with prolonged contact. Lasers and their ranges, versus missiles and their capabilities, then ECM and stealth tech like black globes or etc. The actual combat usually is one round on a fast pass, and two, to as many as they can stand, on a merge.


At the end of the fast pass, as long as the ship drives are not crippled, the players can choose to break off and not get pursued, or to reverse course and make another fast pass or convert to a merge. That round can only happen if the other ship still wants to engage, and I roll a gut check for that ship’s captain. I let the players apply skill levels as modifiers to the success of the merge as well as modifiers on the hit tables when weapons fly.


This is done with just a handful of rolls and without protractors and vector math and all that: the part I always hated about combat of any kind was that it always felt like stopping in the middle of a bar fight to do your taxes. I’m guiding a shard narrative, with a cinematic flow to it; the fun comes in them performing an action and feeling like they did have the ability to steer some of the narrative, and change the outcome, even as I’m controlling an overall plot line. Thanks for reading!