Category Archives: IMTU

In My Traveller Universe. Alternative non-canon settings.

The Major Races in an ATU setting

There are six major races in the Official Traveller Universe. All are very well described in a number of books in different Traveller rules versions. This is a good source of information to help you with the races for your own Alternate Traveller Universe.

The problem with the major races in the OTU is that they all are placed in the OTU and a few of them may be difficult to re-use your own ATU. Described below are my opinions (in alphabetic order) why the races may be good or problematic for re-use in an ATU.

There are lots of reasons for creating your own ATU. One reason may be that you are bored with the OTU, another that you don’t like all the conflicting canon and another reason may be that you just want to create your own universe.

Alsn CoynAslan:

Aslan are a race of catlike aliens. Even though that might seem like a sci-fi cliché, the Aslans are well described and would probably work well in an ATU with only some minor changes.

The Aslans have been described at about the same time as the Chanur novels was written. It is difficult to guess what cross contamination that has occurred. My guess is that it was in both ways.

Update: While chatting with Cj Cherryh and Marc Miller about the Hani from the Chanur novels and the Aslan from Traveller, Cj Cherryh said that she has “never heard of (the) Aslan” (from the Traveller RPG).

The DroyneDroyne:

Spoiler warning! Mark the hidden text below to make it visible.

The Droyne is one of the most important races in the OTU. They (as the Ancients) transplanted humaniti to many worlds in charted space. If you don’t want this in your ATU, then the Droyne cannot be the ancients.

The Droyne is well described and would work well in an ATU as an old mysterious race. You may want to ignore (or change) the secret part that is hidden above.

Hiver CoynHiver:

The Hivers are the starfish aliens that actually are starfish. They are also good at manipulating other races to do what they want. They are also very good at mathematics and use a base-6 system. Their computers and robotics are very advanced. The Hivers don’t like ground combat and use other races to help them with that.

The Hivers could work well as a strange race in an ATU setting.


There are the Solomani, the Vilani and the Zhodani and lots of minor human races. In the OTU all human races (except the Solomani) has been taken from Earth a long time ago and they have then evolved independently. This may seem like a stupid idea to re-use in an ATU unless you are a trekkie or likes von Däniken.

Humans from Terra (Solomani) can be borrowed from the OTU. But these are not the good guys, so you may want to change them.

Other human races will be more difficult to re-use in an ATU.

K'Kree CoynK’Kree:

These are horsemen or centaurs. In the early versions of Traveller, they were actually called Centaurs. I think they can be a good foe in an ATU with their vegetarianist agenda.

Big strange races like this (with strange motivations) usually work best as NPCs.


In the OTU these dog people are uplifted Terran dogs. Although Vargrs are one of the best described races in Traveller, they belong in the OTU and cannot really fit into an ATU as they are described.

If they are uplifted in another way than in the OTU or if they are not actually dogs (just like the Aslan are not cats) then they could work.


Works well: Aslan, Hiver, Solomani, K’kree

Problematic: Droyne, Vilani, Zhodani, Vargr


Benford’s law, or why you shouldn’t use a D10 for generating some random numbers

This applies to all games where you want to generate a random number to describe something. In many cases you cannot just use a D10 since Benford’s law says that the lower numbers will have a higher probability.

Benford's law
Benford’s law – Public domain

This law is usually true when applied to things that grow exponentially. Like the population modifier digit (the P in the PBG-number) in the extended UWP for Traveller. Why is it so? Here is an explanation! A shorter explanation is that to change the first digit from 1 to 2, the population needs to increase 100%. To change the first digit from 8 to 9 the population needs to increase 12%. This means that the population digit will stay longer at lower values and therefore the lower values will be more likely.

Something else that is interesting for Traveller, Benford’s law can also be applied on asteroid sizes, since these has been built up of smaller objects over time.

It can most likely be used for anything that is big and varied enough like the size of buildings, the size of villages or towns, the size of space ships etc…

If you use a D10 to get a first digit for something that should behave according to Benford’s law, you will create a statistical anomaly. Doing it for one, or a few planets doesn’t matter, but if you do it for the P in the PBG-number of a subsector or something larger the result you get will be very unlikely.

So stop using that D10 now! Write a simple program on your calculator or computer that calculates the first digit according to Benford’s law!

For those who still (for some reason) needs to use dice, here is a table with a distribution that is close enough to the Benford distribution using 2D6, like you should do in Traveller.

2D6 First Digit
2 1
3 7
4 5
5 3
6 1
7 2
8 1
9 4
10 6
11 8
12 9

Just for fun, test Benford’s law for a number of datasets. It works!

The Regretful Historian

Patron: Academic
Required Skills Those need to operation a starship
Required Equipment: None
Locations: Mullingar, Enniskillen

Players’ Information:
The characters are between jobs on Mullingar when they are contacted by Professor Dugan O’Fallon of the Mullingar Institute of Historical Research (MIHR).  MIHR is an academic organization that uses a substantial endowment from the local government and numerous corporate contributors to fund historical research and archaeological expeditions.  Professor O’Fallon is a well-respected member of MIHR, having written many popular books on the early history of the Eire subsector.

The meeting takes place in the Professor’s office at MIHR in the late evening hours. The professor has seen many a day under alien suns, as his cracked and leathery complexion attests.  He is not well, occasionally getting short of breath as he speaks, and taking breaths of supplemental oxygen from a respirator mask.

“Two months ago,” he says, “I hired an archaeological team for an expedition on Enniskillen.  It wasn’t sanctioned by the Institute – I paid for this one out of my own deep pockets.  You see, I have a personal passion for the history of this subsector, and the team I hired shared my particular passion for this subject, so they were all very eager to go.  Unfortunately, the political situation on Enniskillen has deteriorated to the point where there are a number of armed resistance groups opposing the local government with acts of terrorism and violent confrontation. As the expedition is now two weeks overdue, they may either be victims or unable to leave the spaceport.

“The mission is three-fold.  First, I want you to travel to Enniskillen to determine what has happened to the expedition.  The independent Far Trader Longshot will be lifting tomorrow morning and I have low berths reserved for each of you, along with two tons of cargo space for any possessions and an ATV, which you’ll need for the second part of the mission.

“Second, I want you to rescue or recover the team and its equipment, including any and all data and artifacts it has collected.  There is a packet aboard the ATV that will have the details you’ll need to determine approximately where the team was going and their most likely route.

“Lastly, there is a Far Trader starship – Lady Starshine – that the team leased from an outfit here on Mullingar.  The vessel needs to be returned here within the next month or the deposit will be forfeited and an additional financial penalty will be assessed against me as well.  That last part is important because I used Institute funds to pay that deposit.  If the deposit is forfeited, the scandal will end my tenure with the institute and my career as a historian.

“Your payment will be fifty thousand credits, reimbursement of your legitimate expenses, and a bonus of up to ten thousand credits, depending on your timeliness and your ability to keep things quiet enough to protect what is left of my reputation.  Time is of the essence, so I’ll spare you the formality of haggling for a better price.  What I am offering you is literally all the material wealth that I can spare.  I’m hoping you’ll say yes.”

Referee’s Information:
Enniskillen is currently experiencing a period of local unrest due to the actions of its government.  Specifically, the government has engaged in a series of unpopular policies that have the appearance of benefitting members of the upper economic classes at the expense of the working classes.  The government’s bureaucracy has become more insular of late and has been accused of using unfair and illegal practices to exclude all but the most favored members of the upper classes from being candidates for government employment and obtaining contracts from government agencies.  This has spawned a series of popular protests as well as several extremist terrorist organizations which have made conditions in the main starport’s city, Dunbailey, somewhat precarious for travelers and business professionals.

Enniskillen is a poor, desert world with much of its surface a trackless wasteland of sand and stone.  Archeological evidence suggests that during a wetter time in the planet’s ancient past there may have been a sentient species.  The current site drawing attention is a collection of what appear to be burial mounds discovered nearly five hundred kilometers southwest of Dunbailey.  Due to the current political unrest, the government has prohibited all aerospace traffic (save spacecraft) from its skies until the current crisis has ended.

1. The team is stranded.  Professor O’Fallon’s team is stranded near the archaeological site in the desert after a particularly vicious sandstorm has disabled their vehicles and communications equipment.  The characters will have to venture overland to find them and return them to the starport, facing various terrain and animal hazards along the way there and back.

2. The team is being held hostage by terrorists.  The Professor’s team has been mistaken for corporate prospectors by the locals, and a terrorist faction of the Liberation Coalition is holding the team hostage in exchange for the release of several prisoners held by the government.  Luckily for the characters, the terrorists are a fledgling organization without much experience in these activities, giving the characters a shot at rescuing the team members.  The referee will have to generate the terrorist faction members as well as map out the location where the team is being held.

3. The team is being held by the government.  The Professor’s team has been swept up in the local movement and has been arrested by federal law enforcement for aiding terrorist acts.  The characters will have to negotiate with the federal authorities to secure their release or mount a much more difficult rescue mission from a protected facility.  The referee will have to generate the federal guards and officials, plus map out the facility where the team is being held.

4. The team is hospitalized.  The Professor’s team got caught in the crossfire during a particularly violent confrontation between the Liberation Coalition and the government.  In the chaos following the confrontation, the team was taken to separate hospitals with severe injuries and their records were lost in the haste to treat so many victims.  The characters will have to investigate the situation in order to locate the team members and transport them back to Mullingar.

5. A rival has stepped in.  One of the Professor’s longtime rivals got wind of the expedition and hired a mercenary team to kill the team members in the remote desert.  The rival has also taken steps to disable the Lady Starwind so that it cannot be easily returned to Mullingar.  The characters will have to locate the team, salvage their notes and data, repair the starship and prevent the rival from delaying them further in order to meet their deadline.

6. The expedition was a ruse.  One of the terrorist factions in Liberation Coalition sent their agents to MIHR to solicit funds for the expedition from the Professor and intends to purchase arms and explosives from their sources in the black market.  The characters can work with the local authorities to recover most of the money, or thwart the terrorists’ actions personally.

Spherical Space Ships

In science fiction we have seen lots of spherical space ships. We remember the ships used by the Space Vikings by H. Beam Piper and the Death Star from Star Wars and the Heart of Gold from the The Hitchhiker’s Guide to the Galaxy and the ship from E.T. and the Borg Sphere from Star Trek: First Contact and lots of more.

Space Viking - Mercenary Cruiser
Image from Project Gutenberg. Copyright expired.

In Traveller we have the Mercenary Cruiser and the Tigress class. We all know that the Mercenary Cruiser is supposed to be able to land. But in Traveller it cannot do that since it is only partially streamlined and the rules say that it then cannot land. I think it should be able to land under certain conditions. These conditions might be a slow decent and no flying in the atmosphere. For a quick assault, the cutters would still be needed.

Some pretty pictures of the Mercenary Cruiser:

Some pretty pictures of the Tigress:

Peter Elson, who has painted a lot of the images for TTA (that we love) has also made a spherical ship. This ship is also able to land in an atmosphere.

The Long Result by Peter Elson.
The Long Result by Peter Elson.
Posted by permission of the estate of Peter Elson.
© Peter Elson.

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.

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.