Traveller Miscellaneous

Realism in Sci Fi

sparked by forum thread


Obviously arguing over realism in a sci fi RPG doesn’t make sense any but regardless my preference is that sci fi defaults to everyday realism except where a specific technology explains the difference.

So in “Outland” although the sheriff is in a futuristic space station he has a standard shotgun so in the shootout it still obeys the rules of standard shotguns. If it had been shown earlier that he had a pistol firing heat seeking missile bullets then it could have been different.

So imo, default to realism *except* where the setting’s future technology explicitly negates it.

This is the context behind why arguing over stuff like the existence of pirates in Traveller makes sense imo. My preference is realism can be negated explicitly on a case by case basis by specific technology but otherwise default realism applies.

Hence for me instead of “if you swallow an elephant sized unrealistic premise (e.g. jump) why not just swallow every gnat-sized unrealistic premise?” I prefer to treat each gnat and each elephant individually to minimize the elephants.


Another aspect of the gnat vs elephant thing is individual knowledge might make one thing seem like an elephant to one person while it is only a gnat to someone else.

For example someone who knows a lot about weapons might have an elephant sized problem with something related to weaponry that is a gnat to most or someone who knows a lot about navies or someone who knows a lot about physics might find the FTL / jump thing an elephant while others don’t.


Personally I like “realism” convos as even though it’s just a game I like my handwavium to turn as many elephants into gnats as possible – dunno why but I like it.

For example since watching Interstellar my jump handwavium has become dimensional – the ship slips into the 5th or whichever dimension and in that dimension you can align the line between the point you’re at and the destination point in 4D space until they are in the same spot in 5D space and then you simply exit 5D space at the destination – so you barely move at all let alone FTL, you just slip into 5D space, rearrange the geometry and then slip out again.

Now I’m not saying that is any more plausible than the earlier handwavium but as far as I’m aware no one has yet *proven* that the laws of physics which apply in 4D space apply exactly the same way in 5D or 6D or 10D space.

So for me that shrunk that particular elephant a bit.

Multiple Colonizations


Example (using 3I history)

  • Planet A has a native sentient species
  • Colonized by Ancients who seed with Vargr and use them as hunting dogs for sport hunting the
  • Ancients disappear, Vargr devolve and become primitive “natives” on best land, original natives
    survive on marginal terrain
  • Vilani colonize – Vilani humans dominate both previous natives
  • Vilani collapse, Vilani colonists lose high tech advantage and get pushed off continents by Vargr to islands
  • RoM colonists, take over main island of surviving Vilani, interbreed, ignore smaller Vilani
  • RoM colonists push into main continents dominating Vargr and original natives in the areas they
  • RoM collapse leads to stalemate, RoM colonists can only produce mid-tech on planet so other
    groups close the gap
  • 3I colony arrives, takes over main island of RoM/Vilani and rebuild spaceport


End Result

  • original natives in marginal terrain on the continents
  • Vargr turned native over half the continents away from coast
  • RoM/Vilani turned native with a vargr underclass on the half of the continents near the coasts
  • Vilani turned native on various small islands
  • 3I and RoM/Vilani on the main spaceport island with 3I dominant.
  • ruins everywhere: native&ancients, Vargr, Vilani, RoM etc


I might create a tabular system for generating results like this sometime.

Realistic Star Faring

applied to the Traveller setting.


I forget the exact numbers but IIRC earth has been around c. 5 billion years or so and sentients only about a million years, agriculture only ten thousand years and potentially pre-stellar for only a hundred.

So even with an assumption of one potentially earth like planet/moon per system then if they all formed at different times I think it comes to around one in five thousand systems where the planet has been around long enough for life to have started and long enough for life to reach cavemen.


If the average Traveller sub-sector has say c. 30 systems then a full sector on average has c. 500 systems so that would mean one system had reached an alien version of neanderthals per 10 full sectors.

Sentient aliens with agriculture would be around one per 1000 sectors and pre-stellar aliens one per 100,000 sectors.

The entire Imperium is like 20 sectors.


Those sums are probably very inaccurate but they illustrate the idea that the first species to interstellar is going to find sector after sector of planets that are only partway to being livable and of those that are livable most will only be partway to producing a sentient species.


So if humans were first then I think the logic of it is the first star settlers would expand out exploring in all directions and as the people who do the colonizing will be the sort of people who want to do it then if they produce similar kids the process becomes self perpetuating.

In the Traveller setting most of this early colonizing wouldn’t actually be colonies to live on; it would be building stepping stones for refueling for the next jump but it would be necessary to get tothe next step and the people doing it don’t stop because at the beginning of the process people were selected who were the sort of people who couldn’t stop.

Eventually they’d arrive somewhere that had a real world and pre-sentient alien monkeys. Generally I think taking the top niche in the food chain would prevent any native pre-sentient evolving naturally so that species would be blocked unless quarantined but maybe the humans would uplift them just for the novelty. They’d uplift planets for sure or at least start the process.

So they’d spread everywhere, living in domes a lot of the time while speeding up planetary evolution. In most places their presence stops a native sentient developing but  maybe they uplift some themselves gradually adding Wookies and Ewoks to their ship’s crews along the way and just keep spreading because they can’t stop.


So one option – humans are first and spread like a wave in all directions until after 50,000 sectors or so of colonizing mostly rocks and the occasional monkey world they eventually bump into another star faring sentient species.

Which is a bit like the Ancients in the Traveller setting.


Useful Links


Spacey Science Stuff


Traveller Specific


published world maps & info

jump shadow



submarine tour (400 or 600 dton in Traveller terms


liberty ship (2000 dtons)





Vilani: GURPS Interstellar Wars

Hydroponics / Life Support:  T4 Fire, Fusion and Steel

Megatraveller: Imperial Encyclopaedia



worth thinking about space elevators re temp space ports


Campaigny Stuff

LBB only

Adventure Ideas

As they come

1) Tiger Hunt

Players on a backwater planet after doing some favor for a local Prince (maybe just bringing some trade goods for example) get invited to take part in a Tiger hunt. The transport is the local equivalent of elephants and the prey is the local equivalent of tiger. The elephants have armored drapes protecting them but the Prince’s elephant’s armor is sabotaged (either allows tiger inside under elephant’s legs leading to panic or through falling off taking the Prince’s howdah to the ground). Players need to save the Prince and then find the culprit.

2) Artist

Remote, corrosive atmosphere, fluid ocean, (could be prison planet: Glisten/Mithras?) – reclusive artist in residence in some abandoned rock tower / research / lighthouse type building collects fluid from rock pools at low tide and uses it in a form of hitech glass blowing to create famous and valuable art. An art collector too far down the waiting list is in a hurry and wants one stolen or agent wants news – artist hostage of dudes planning prison break? Sealed tower has submersible entrance maybe, environmental hazards, weird critters, maybe a prison break involved – mini trek through dangerous terrain followed by mini dungeon followed by main scene and escape.

3) Magnificent Seven

Think Galaxy Quest. System under attack from pirates / renegades / bandits. Player ship attacked and crash lands. Wrecked colonial cruiser on ground. Players can get cruiser partly working with parts from their ship – no jump, 1G, some weapons etc. Pacifist natives can make up bulk of crew but need players to direct. Bk 2 ship battles with Vargr corsairs or something.

4) Space Janitors

Contracted to travel through a number of systems performing maintenance on navigation satellites. Come across satellite warning of a gravity rip-tide out of position with physical damage – repairing it find organic material like blood, (Byakhee crashed into it – hurt – smashed it.) Byakhee dropped onto planet nearest original position to heal up. Blood analysis triggers open anomaly report with a significant bounty.



General Ideas

from around

Scout/Small Ships

1) movable partition walls -> 4 x cramped state rooms, 2 x okay size, 1 x large

2) TV walls – programmable electronic wallpaper

3) ambient sounds

4) hitch hikers

5) scout couples – even families

6) scout service report database – updated at star port, search on a planet for fugitives, missing persons, anomalies etc




In Classic Traveller, Marines gain cutlass skill at basic training. This makes no sense but going with it for the sake of argument you could say that’s how they train vacc suit and zero-g combat. Marine ships and bases have zero-g training courts like squash courts with a viewing platform for spectators that involves dueling with cutlasses – bouts are a bit like jousting as contestants have to push off surfaces and strike as they pass.

This could then have turned into a major sport.



Jack of All Trades

Could treat JoT as a natural talent for a related set of skills. Characters pick one when they get it and it gives the equivalent of rank-0 in that set of skills.


  • JoT (repair)
  • JoT (melee)
  • JoT (ranged)
  • JoT (animals)
  • JoT(starship) (imtu scouts are get trained with this at basic but in reality are selected on the basis of having this as a latent natural talent)