A downloadable game

Buy Now$15.00 USD or more

A GMless tabletop roleplaying game for three players. It tackles themes of diaspora and homecoming; about receiving and committing violence; and a game about struggling to shape events far larger than the individual. It poses questions about colonialism, culture, and bodies.

This game provides a textual framework that will be populated by what you bring to it. It tells a larger story inside which you will have the opportunity to situate your smaller and more personal tale. The plot will proceed through a number of predetermined steps and stages, but what those look like and what outcomes arise from them are largely your responsibility to flesh out.

You as the players will always have the power to contextualize how your own characters are impacted by larger events. You get to choose how you react to the grand sweep of history in the making; how you cope with your own struggles; how you help those close to you; and how you change the world.

Your characters are members of a persecuted cause fleeing the solar system in a ragtag fleet of spaceships. After you escape and find a reprieve, you must decide what your return to earth looks like. Your story follows an elliptical path, soaring out from Earth but eventually—inexorably—being drawn back by the gravitational pull of all that you left behind. 

This game draws thematic inspiration from the podcast Friends at the Table; Heaven Will Be Mine, by Worst Girl Games; and the works of C. J. Cherryh. It takes mechanical inspiration from Downfall, by Caroline Hobbs; Fall of Magic, by Ross Cowman; Follow, by Ben Robbins, and Mobile Frame Zero: Firebrands, by D. Vincent Baker and Meguey Baker.

Written by Tomas Herbertson. Art by Sasha Reneau. Editing by Basin Herbertson and Emily Anzalone.


Buy Now$15.00 USD or more

In order to download this game you must purchase it at or above the minimum price of $15 USD. You will get access to the following files:

CBOM A5 spreads.pdf 4 MB
CBOM playsheets printable.afpub 757 kB
CBOM Online Playsheets.docx 162 kB

Exclusive content

Support this game at or above a special price point to receive something exclusive.

CBOM community copies

Free to claim for those who are economically disadvantaged. For every copy of the game sold, one community copy will be added to this pool.


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Watch me read through this game and write this review here: https://www.twitch.tv/videos/693675613

Celestial Bodies, Orbital Mechanics is a deeply intimate character and community game. The story it’s telling is specific, but you will bring so much personal love into the narrative built together. If you like games with grand story arcs but don’t have the time, this game is perfect for you! How it tackles diaspora, community, and colonization is beautiful and thoughtful. 

Some things I absolutely love:

  • The Map is incredible. Aesthetically, narratively, innovatively, I love it. It’s both an actual map and frames the narrative orbit that you’ll be playing.
  • I love how the roles are laid out, this game is GMless in a very nice and approachable way!
  • The character table is full of great and simple ideas that go a long way, worth grabbing even for other sci-fi games!
  • The halfway point is brilliantly brought on! This game knows how to take you through learning it and then asking you to make thoughtful decisions about the story moving forward and your own characters. For how much the game gives you specific prompts and has a specific story to tell, CBOM is wonderfully approachable and open to you taking the wheel
  • How it treats your characters at the end of it all is beautiful and harrowing. It truly knows “living with pain past the moment of violence.”

I bought it for $15 and it’s definitely worth each buck! I can’t wait to play this, and as a designer, I will definitely be thinking about this game and how it works moving into my own stuff! Please buy it