A downloadable exploration TTRPG

Play test video four is live: Under a Hostile Sun - Playtest IV An authentic look at the ongoing development process.  Watch to our players explore a Moon Mason Bee hive!  

The settlement’s life support is at the brink.  A solution to this world’s dangerous conditions must be devised & corruption amongst the station leaders must be investigated. But the Void of Space was not meant for Man. These planets are not “Mother” like Earth – you are under a hostile sun.

  • A rules-lite exploration-focused RPG.  There is no combat system - rather the enemy is the brutal environment you are trying to survive in.
  • Rules light but exciting system for Environmental Encounters that encourages risk vs reward decisions.
  • Currency system that allows easy tracking of resources mined from the planet.   Find alien creatures to produce even rarer resources - maybe even the Prime Matter- unlimited potential- itself.  
  • Play mat allows for resources to be easily tracked with Poker Chips or coins.  Just place the chips over the corresponding resource picture.  
  • Illustrated with Adobe Fresco/Photoshop/.  A redesigned book done in Adobe InDesign coming soon.  

Left "A.C." contributed this and is a member of the East Bay Martian Society

The galaxy recently had a great upheaval.  Now many, seeking to escape corrupt local governors and war-ravished worlds, are desperately taking to space exploration.  It's a hope for a better life.  But at a cost.  The planets explored will include environments not easily inhabitable - volcanic hellscapes, colossal storms, radiation and more.  But with some grit, and a firm faith in the Immutable, maybe, just maybe, you and your brave team of settlers will be able to survive and greet the alien sun, not as an existential threat, but as a friend.  

As playtesting goes on, rules will be updated.

Updated 10 days ago
StatusIn development
CategoryPhysical game
Rated 4.7 out of 5 stars
(3 total ratings)
AuthorMartian Muckraker
GenreAdventure, Role Playing, Survival
TagsAction-Adventure, Action RPG, rules-lite, Sci-fi, Space, tabletop-role-playing-game


Under a Hostile Sun Core Rulebook-2024.pdf 3 MB
Under a Hostile Sun - Galactic Masters Guide - 2024.pdf 4 MB
Under a Hostile Sun - Quick Reference.pdf 290 kB
HostileSunExtras.zip 75 MB
Playmat Character Sheet -Hazard_Placards.pdf 300 kB

Development log

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A character sheet template that allows for easy tracking of resources is now available on PlayRole

Update- the Demeter VI adventure now has been edited to reflect the change from fixed opportunity to an Opportunity Die, and new tokens, maps and creature cards have been added.

Episode III shows my playtesters learning the new Alchemy system! They enjoyed the wide range of creativity and ease of use.

Episode II of our playtest is up! And I was able to adjust OBS Studio to prevent audio clipping. Let us know what you think, what questions you have and what you would like to see!

And any likes help us share the game development process with others.

(1 edit)

See the ongoing development process in action! First of (at least) 3 recorded playtest videos coming.

We have a Trailer now!!! Show it some love so we can appease the Great Deity Algo Rhy Thm and share the game with others!