Unique Tech Development
How would tech develop? I think it would depend on the setting.
If your setting has a lot of species on lots of planets that all uniquely developed high tech up to space faring then they should all have their own – potentially uniquely weird – tech tree and tech levels.
On the other hand assuming most sentient species were pre sentient for c. 80% of their total history and pre spacefaring for 99.99% of it and even pre-agriculture for 99% then the first jump-capable species are likely to have a massive head start in their part of the universe with up to 80% of the other species they encounter on other planets still at an animal level of development and maybe another 19% stone age and only 1% agricultural and above.
So if in your setting you roll for each hex on your map with 4-6 meaning the hex contains a system and say 4 = uninhabitable world, 5 = inhabitable impaired and 6 = inhabitable world and specify that sentient species only naturally arise (usually) in the habitable planets then you have 1 in 3 systems times 1 in a hundred or 1 in 300 systems where the sentient species is post stone age and even then most of them would be pre-industrial – say another 2D6 roll with 2-10 pre-industrial 10-11 industrial and 12 space faring – so basically there’ll be very few worlds in the vicinity of the first species to get jump who will have started on a unique tech tree yet (even if there were plenty in the universe as a whole).
So in total that would be 1 in 6 hexes with a habitable system with a 100:1 chance of agriculture per habitable system and 1 in 6 chance of industrial+ so c. 3600:1 chance per hex of unique post industrial tech. In Traveller terms of 80 hexes per sub sector that’s about 45 sub sectors so roughly one partially unique alien tech tree per three sectors. So a species with unique tech might expand across multiple sectors, meeting hundreds of other pre-industrial species before they met one who were industrial.
If so you’d only need to know the tech tree and level of the first species because their tech would short-circuit the other species’ development. The other species would learn the first species’ tech tree not develop their own – at least not unless they surpassed the first species in some field or maybe in some tech specific to their world’s environment. The tech tree of the non core planets would be the same as the core civ’s tech tree and each planet’s tech level tech level would be what each planet can produce or maintain locally – plus assume they can maintain equipment one or two tech levels higher with imported spare parts and thirdly assume they can maintain imported tech of the primary civ’s default tech level if they import technicians as well as spare parts e.g. the President has TL12 vehicles on a TL7 world.
Then you have a third option of there being a primary civ in a particular part of space which eventually collapses and their various subject species and colonies revert back. In that case do they revert back far enough to develop their own tech tree or does one or more of them just eventually relearn the first species’ tech again? If on one of the planets a corrupted Ancient’s database survives and the species on that planet eventually relearn part of the same Ancients tech tree and become the new dominant species we’re back at option (2) – single tech tree (although maybe with gaps in it.)
This scenario does allow room for a second roll for uniqueness. If tech reverts and then rebuilds there’s a second chance of uniqueness so one of the original colonies might develop in a unique way the second time. So say a single ancients tech tree expands across 3-4 sectors, 40-60 sub sectors encountering only one at least partially unique tech tree but after the collapse and rebirth there may be another 1-2 other unique trees spawned by the rebirth.
So it depends imo – although as even in option (2) and (3) there will be some species / colonies who undergo some unique development I’d say the best solution is the usual best solution – random tables!!
The tech tree could be split into broad categories and each category rolled separately to see if they followed the default pattern or not. Then if option (1) you use the tables for each species and in option (2) or (3) you pick out one or two species / reverted colonies per sector and use the tables. In the latter case you might first roll 2D6: 2-8 = one. 9 = two, 10 = three, 11 = four, 12 = all five, unique categories. A universal tech profile might then be a TL followed by “R” for regular or “U” for unique in each of the categories e.g. TL03-RRRRU.
You wouldn’t need to specify it until the players bumped into the planet.
Example: you might have a primitive herding planet with very advanced tech priests who discard everything they think might destabilize society except melee weapons so they have TL18 antimatter swords but nothing else.