The Revenant Sandbox

Last week, I made the case for writing adventures, not systems. This week, I decided to follow my own advice and continue the preparation for my sci-fi sandbox. I’ve posted before about the most important NPC in your sandbox, but I haven’t addressed the sandbox itself. So this is the entry in which I start the work on a sandbox! 

Behold, the Revenant Sector!

The black dots are solar systems without descriptions.

Getting started

I used Stars Without Number: Revised Edition’s Sector Creation chapter (p. 129). A rough outline of its process is to roll: 

  • d10+20 to find the number of worlds.

  • a couple of world tags per world on a sweet d100 table.

  • Atmosphere type. 

  • Temperature or climate.

  • The world’s biosphere. 

  • Population.

  • Technology level.

It is possible to get some conflicting results, such as a frozen planet, which ostensibly has all its gases liquified or frozen. Otherwise, it’s a very effective way of creating a diverse range of worlds. The author advises to continue generating worlds while it is fun, and I find this to be sound advice. You can get by with 1 world, while 4 worlds is a good start for a first session. Remember, most of the Expanse tv-show took place in just one solar system - just having a few worlds in one system gets you far as well. 

I took the time to generate 10 worlds out of 26. I intend to generate them all and then add some. In addition to the basic details from the Sector Creation chapter, I also added some points and keywords.


What I found was that I ended up also adjusting a few planets according to either atmosphere or climate. For example, a few of the frozen planets were turned into airless planets. I also re-rolled world tags that I felt didn’t fit, such as the “psionics” related tags. It’s your sector, so you can do what you want. The result won’t become worse if you don’t follow the result of the dice. Sometimes the combination of tags, possibly also technology level, can produce some strange results. At this point, you may again have to re-roll or just think very creatively. 

One of my strangest examples was a neolithic tech-level world which had “pretech worship” and “post-scarcity”. How could this possibly work? Well, my solution was the following: 

Narrower scope

At this point, you can get more specific. Maybe you can make a list of major celestial bodies, perhaps using the table I added below. Add your world independently of all the planets you roll. For simplicity, you can also add 1 asteroid belt and +1 for every two gas giants you have. In addition to a list of celestial objects, you should have the following points:

  • A starport.

  • A spaceport (may also include a space elevator (

  • An interesting surface site.

For the first session, you can start off the players without a ship, and maybe make the first session about how to get one. A highly regarded scenario for this could be the “High and Dry” adventure for Traveller. Another alternative is to simply give them a ship, a rust bucket, with a debt associated with it. If this is the case, then you may find that the players want to visit another star system. Perhaps they load it up with something they can sell another place. 

If you need some quick floor plans for an interesting site, you can always check out the Starship Geomorphs, which are excellent to use. Another handy resource is the Dead Planet book for Mothership. It has a very useful set of tables for quickly rolling up derelicts, which when combined with the Starship Geomorphs can be very effective. 

Another thing to consider is to prep for encounter areas that the players are likely to come across if they visit a planet. I have made a diagram that may be useful for that purpose: 

Furthermore, a kit that I find to be indispensable is Augmented Reality, which helps bring life to a cyberpunk style city as you run it. There are also very useful tables in 2400 by Jason Tocci. Jim Parkin’s Any Planet Is Earth is also a great system and toolkit, which I absolutely recommend for this stuff. Even if you don’t use the game, the tables are really handy while running the game. 

The Revenant Sector so far

So far I have been able to write descriptions for the upper half of the sector, about 11 worlds. If you are curious, you can read about them here! So far, they are more prompts and improv triggers than full texts. That’s fine for me, I usually develop it more once I know where to put the focus. Such a direction is often set by the players clarifying their goals. 

The work-in-progress sector sheet can be seen here.

 The next steps will be to:

  • Finish the remaining world descriptions. 

  • Write more elaborate world descriptions for the players.

  • Write some job tables. 

  • Improve an old trade table I wrote. In the meantime, I’ll depend on Traveller’s trade table.

  • Write some short adventures.

This is an ongoing project and I will tag relevant material with a “The Great Filter” tag. My next blogpost may not be about the Revenant Sector, but more are in the works.

Thanks for checking this out! 

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