Category Archives: IMTU

In My Traveller Universe. Alternative non-canon settings.

My house rule for planetary size

A problem with the random generation of worlds in Traveller is that for small worlds (where size < 4) is that these worlds might get an ordinary breathable atmosphere. This is a problem, since the minimum molecular weight retained for a planet shouldn’t allow that. EDG has explained minimum molecular weight retained here, and here is a nice visual tool for checking what gases will be retained depending on size, density and temperature.

This problem leads to silly explanations. Like the one in both the GURPS and Mongoose Sword Worlds modules where a planet (Enos) is made of Osmium. Other explanations might be terraforming by the ancients.

These silly explanations might explain how a few (very unique) worlds got their atmospheres. But it seems unlikely that these explanations can explain every world equal or smaller than size 3 with an atmosphere equal or greater than 2. In an average sector with standard stellar density there are about 80 such worlds. (In the Spinward Marches, there are 73 worlds with this problem.)

I usually ignore this problem, since our group of Traveller players don’t care about details like this. They want to play the game. But if the question is asked, I now have a solution. Instead of explaining every world or changing the UWP, I use this table.

SIZE DIAMETER miles DIAMETER km
1 4000 6400
2 4500 7200
3 5000 8000
4 5500 8800
5 6000 9600
6 6500 10400
7 7000 11200
8 8000 12800
9 9000 14400
A 10000 16000

As can be seen is this table, the problem is solved by making the smallest planets big enough to retain a breathable atmosphere. (The original table can be seen at Traveller Map.)

Terraformed Mars
Terraformed Mars: File from wikimedia. Licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

0602 Derry

One of the first worlds settled in the Eire Subsector and still of significant importance, Derry in recent centuries has become overwhelmed by tension between the system’s different human populations. Intractable disputes over political allegiances, ethnolinguistic communities, and attitudes towards human biological diversity and evolution may yet produce catastrophe.

Subsector History

The first inhabitants of the Derry system were travellers from Earth, distant descendants of the crew of the ESA generation starship Niall Noigiallach. Funded by the European Union member-state of Ireland, the Niall Noigiallach was–like the other generation starships of its class–modelled on the three vehicles of the European Space Agency Long-range Colony Mission launched in the mid-21st century. Carrying two thousand passengers and ten thousand embryos, the Niall Noigiallach was launched in 2089 with the goal of establishing an Irish colony world hundreds of parsecs to rimward of Sol, in a cluster on the fringes of the Local Arm.

Unlike many other Terran generation starships of that era, the Niall Noigiallach survived to reach its destination, in 4688 CE decelerating into orbit of the most clement garden world in the Dublin binary system (0706 Eire). The mainworld of Baile Átha Cliath and its ancillary worlds were colonized successfully, implementing the long-dead social planners’ design to create a distinctly Irish interstellar-capable society. Completely isolated from their home system and its interstellar civilization, by the 49th century CE the Dublin system supported a thriving civilization capable of mounting secondary colonization and expeditionary missions of its own.

Among the first launched was to the Feabhal system four parsecs away, where an unusual double planet had been detected during deceleration by the Niall Noigiallach, orbiting in the life zone of a young BY Draconis star. On arrival, the Bréanainn V expedition determined that the scans by the founding generation starship were accurate. Six planetary bodies orbited the K5 star Feabhal, four rocky planets and two gas giants. Two rocky planets shared the second orbit, 0.49 AU from the primary, one a high-gravity waterworld with an ammonia-water ocean, the other a desert world larger than Mars in the Sol system with some glaciated seas, both orbiting a common centre of gravity in a bit under two months. Although the system was only fifty million years old and the Feabhal system’s worlds were geologically unstable, both worlds in the life zone–Doire and An Ghealach, in Galanglic “Derry” and “The Moon” did support basic microbial life, while the planets and smaller world of the system were rich in mineral resources. In the end, the Dublin government chose to concentrate its colonization efforts on more Earth-like worlds such as An Baile Meánach (Ballymena), Béal Feirste (Belfast), Corcaigh (Cork), and Gaillimh (Galway), where fully-fledged daughter civilizations could be settled, but the worlds of the Ferbhal system did receive more than their fair share of research settlements, whether floating on the oceans of Doire or anchored on the sea floor, or on the dryer surface of its moon.

Dublin and its interstellar community were brought roughly into distant contact with Sol and its interstellar community in 5346-49 CE, when the prosperous but technologically backwards subsector was conquered by Solomani migrant fleets fleeing instability in the Banners and Ahriman Sectors and attracted to a promising human civilization free from the instability of home. Equipped with jump drive and otherwise vastly more advanced than the worlds of the “Eire” subsector–Baile Átha Cliath itself was only tech level A and most other worlds substantally behind, while the Solomani were at tech level C–the migrants were easily able to overwhelm the peaceful subsector. The proclamation of the Empire of the New Marches in 5351 established a fully-united interstellar state for the first time in the sector’s history.

The coreward worlds of the subsector were soon overwhelmed by Solomani migrants, the world of Béal Feirste becoming the Solomani’s new homeworld in the subsector, while a Solomani military elite established itself elsewhere. In the more than three millennia since the departure of the Niall Noigiallach, the people of the Eire subsector had come to diverge strongly from the Solomani norm, knowledge of the English ancestral to the Galanglic spoken by the Solomani literally becoming academic to people who spoke only one dialect or another of Irish, with the natives knowing nothing and caring even less of what had happened to their ultimate homeworld and its people since their departure. The biology of the humans of the Eire subsector, too, had come to diverge sharply from the Solomani norm, the genetic engineering that had adapted the settlers of Dublin to life on a low-gravity world with a thin atmosphere and an unusual number of allergens creating a variant human race. Various of the secondary colonization missions brought Dublin colonists to new worlds with unique conditions meriting further engineering. In all, the Empire of the New Marches identified three broad classifications of subsector natives which would each count as separate variant human races. As elsewhere, the biologically and culturally distinctive subjects of an aggressive empire were treated badly, often exploited as labour on many of the secondary systems (like Derry’s) opened up by the Empire’s superior technological base

By the end of the 55th century, internal squabbles in the Empire’s governing classes along with a native resurgence on Dublin and the worlds to rimward led to the Empire’s collapse. Solomani retreated to the coreward quarter of the Eire Subsector, where they founded a Solomani-supremacist Empire of Man centered on the world now known to its Solomani majority as Belfast. After some disorder, in 5599 CE the freed worlds united in their Republic, the Poblacht, governed once again from Dublin but now possessing a technological base capable of standing up to their nearest neighbours. Tensions between the Empire of Man and the Poblacht persisted, as irredentists in the Poblacht lay claim to the worlds in the Empire of Man taken by the Solomani, particularly worlds which retained native majorities of population like Doire. Full-fledged war is distant, as neither polity feels strong enough to invade the other, but cross-border terrorism is becoming distressingly common.

Continue reading 0602 Derry

Xexedi Cluster Subsector

I have looked at four more subsectors (one quadrant) of Galaxy One. In the Xexedi cluster, the planet of Xexedi is important since it is a TL-14 industrial planet. There are also many amber zones in this subsector.

@SUB-SECTOR: Xexedi Cluster   SECTOR: Oolite1
#--------1---------2---------3---------4---------5---------6---
#PlanetName   Loc. UPP Code   B   Notes         Z  PBG Al LRX *
#----------   ---- ---------  - --------------- -  --- -- --- -
Lerelace      0912 A466843-C  N Ri                 525 Hc
Laenin        0914 E6537BD-4    Po              R  200 Hc
Xexedi        0915 A476977-E  N Hi In Cp        A  513 Gf
Tibionis      0917 B655743-8    Ag              A  311 Fr
Terea         0918 B7677A7-6    Ag Ri           A  333 Hc
Uscela        0919 A666777-8    Ag Ri              322 Bl
Xeoner        1013 C4577AA-6    Ag                 311 Sl
Esbeus        1015 C677778-6    Ag              A  222 Ff
Maregeis      1019 C777954-7    Hi In              212 Hc
Usle          1116 B677976-9    Hi In              411 Hc
Enonla        1317 A4439CE-D    Hi In Po        R  510 Hc
Biorle        1318 B643976-A    Hi In Po           400 Hc
Diquer        1411 C86679C-5    Ag Ri              234 Hc
Socelage      1414 C665742-6    Ag Ri              313 Fr
Maxeedso      1418 B767777-7    Ag Ri              323 Fi
Anarlaqu      1420 D753755-5    Po                 210 Hc
Razaar        1515 E5538AC-3    Po                 100 Gi
Zadies        1618 B577978-9    Hi In           A  334 Hc

Xexedi Cluster

All maps in this post made using Traveller Map Post Function.

Continue reading Xexedi Cluster Subsector

The Iron Stars Subsector

I have looked at three more subsectors from the Oolite Universe.  The Iron Stars is subsector N. This subsectors have lots of industrial worlds.

@SUB-SECTOR: The Iron Stars
#--------1---------2---------3---------4---------5---------6---
#PlanetName   Loc. UPP Code   B   Notes         Z  PBG Al LRX *
#----------   ---- ---------  - --------------- -  --- -- --- -
Rabedira      0940 B546977-9    Hi In           A  312 Hc
Quzadi        1035 B7779CC-9    Hi In           R  422 Hc
Aona          1036 A445975-D  N Hi In Cp           525 Hc
Leleer        1039 C4449AC-8    Hi In           A  313 Hc
Qucerere      1040 B7577AC-8    Ag                 310 Hc
Biarge        1133 A666777-C  N Ri                 424 Hc
Onusorle      1134 D843954-8    Hi In Po           300 Hc
Usrarema      1140 A6769CB-C  N Hi In              513 Sr
Vebege        1231 E677973-6    Hi In           A  222 Hc
Entizadi      1237 A4469BC-C  N Hi In           A  512 Hc
Rateedar      1331 B576976-A    Hi In           R  414 Hi
Cetiisqu      1338 D543957-7    Hi In Po           210 Hc
Geerra        1434 D456743-5    Ag                 211 Hc
Usanat        1437 D6777AB-4    Ag                 212 Hc
Digebiti      1531 C843956-8    Hi In Po        A  300 Hc
Soladies      1540 C6777A9-6    Ag                 213 Hc

The Iron Stars

All maps in this post made using Traveller Map Post Function.

Continue reading The Iron Stars Subsector

Old Worlds Subsector

You might recognize this subsector? I have tried to make it more travelleresque. Please comment if You have any ideas on how to improve this.

@SUB-SECTOR: Old Worlds
#--------1---------2---------3---------4---------5---------6---
#PlanetName   Loc. UPP Code   B   Notes         Z  PBG Al LRX *
#----------   ---- ---------  - --------------- -  --- -- --- -
Relaes        0121 A8759CC-B  N Hi In              412 Hc
Orrere        0123 C6437CA-7    Po                 300 Hc
Uszaa         0125 C444972-8    Hi In           A  324 Hc
Riedquat      0129 E853873-4    Po              A  210 Hr
Ra            0222 E4208CA-5    Po              A  310 Hc
Diso          0228 B879745-8    Ag                 110 Ff
Leesti        0230 B4409CB-B    Hi In Po           511 Hc
Quator        0322 C777973-7    Hi In           A  222 Hc
Reorte        0324 C8577A7-6    Ag              A  310 Ff
Lave          0328 B5647A5-5    Ri Ag              213 Hc
Zaonce        0530 A5779CD-C  N Hi In Cp           525 Hc
Aesbion       0622 B8979CC-A    Hi In           R  521 Gf
Qutiri        0628 A787875-9    Ri              A  322 Ff
Isinor        0630 C85777A-7    Ag                 400 Sf
Isence        0721 A887874-9    Ri              A  311 Fh
Aronar        0726 C753753-8    Po                 101 Hc
Ontiat        0830 B866879-7    Ag              R  321 Gl

Old Worlds

Map made using Traveller Map Post Function.

My Campaign

Well I’ve finally managed to get a lot of my campaign info up on my website. Please feel free to snoop around and let me know what you think. I am open to advice (this is my first Traveller campaign as a Referee).

The site is far from completed, but take a look at what I do have posted.

Please note that there are non-player races in the campaign, but I have yet to post the info on them. One of them is one of the 5 major space-faring races controlling the planet, so my math does work. 🙂

Thank-you,

~Expat~